Multiply and share your perennials this fall

Gladiolus are beautiful to share with friends.

Have your favorite perennials been looking crowded and not blooming as abundantly as they used to? Maybe it is time to divide them and replant or share them with neighbors or friends. There are actually tables that will tell you how often you should divide your German bearded irises (Iris germanica), daylilies, Coreopsis, Pentstemons, Shasta Daisy, Delphiniums, Achillia (yarrow), Agapanthus and many other perennials; see this table resource for information on dividing over 100 perennials:
Most spring and summer blooming perennials are best divided and replanted in the fall. This is a good time because they are not blooming so energy can go to establishing roots and leaves before winter sets in. Fall bloomers can be divided in the spring. It is good to irrigate a day before digging and it may also be good to trim foliage back moderately for some plants.
Plants should be dug with a shovel or a spading fork. For very dense clumps it is sometimes necessary to use back to back spading forks to pry clumps apart after digging them out or use a hori-hori Japanese gardening knife to tease them apart or a shovel to cut them apart. Some fall perennials have spreading root systems; aster, bee balm, lamb’s ear, and purple cornflower are examples. These plants can easily be separated by hand or cut apart. Each new plant should have 3-5 vigorous shoots and discard non-vigorous plants.
Another perennial group to divide in the fall has clumping root systems that originate from a central clump with multiple growing points. This group includes astilbes, hostas, daylilies, and many ornamental grasses. Keep at least one developing eye or bud with each division. If larger plants are wanted, keep several eyes.

‘Smokerings’ is a prolific iris that will need to be divided every 3 years.

Irises have rhizomes that grow at the surface and as they get crowded, bloom less. They are usually divided every 3 years. The best time to do this is in late summer, but fall is alright too, especially if you have repeat bloomers which should be divided after blooming. Rhizomes should be lifted with a shovel, cleaned and examined. Often rhizomes older than one year without leaf fans attached are shriveled with poor roots. These should be discarded and only rhizomes that are young, healthy with roots and one or more leaf fans attached should be replanted.
Peonies and other plants having a taproot and are not easily divided. Peonies can stay in one place for a 100 years and not get crowded, but if you take care they can be divided and they must be planted at the same original depth where they previously were growing.
Dahlias are a special case that are dug and divided late in the fall. They can be dug a couple of weeks or more after frost kills the foliage. The tubers can be divided after being dug and washed or they can be washed, stored and divided later in the spring when the eyes are more evident on the tubers.
Dahlias can also be left in the ground in the Central Valley since the ground here does not freeze as in most parts of the country. In New Jersey, my mom had to dig them every fall and put them in the cellar away from killing freezing temperatures. However, they are vulnerable to rotting in wet winters here so you take your chances when not digging them. I accept that I might lose a few when I don’t dig them, but always hope my favorites will survive. After 3 years of not being dug they will likely get crowded and need to be dug and divided.
Agapanthus is another flower that will need dividing every few years or the blooms will get sparse. Instructions on how to do this can be found at:
Gladioli are a drama flower I like and they can be dug annually or left in the ground, but if left in the ground they should be divided every two years. Dividing gladiolus will provide double the corms and double the pleasure of growing these gorgeous flowers. I used to leave a few in the ground each year to make sure I had some in bloom to enter in the County Fair Floriculture exhibit each June. I won a lot of best of show ribbons with

Best of Show-San Joaquin County Fair-2005

these beauties. Alas, the floriculture exhibits were discontinued for several years and this year although it was resumed, they had zero entries. Apparently, discontinuity is the enemy of good participation.
If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:

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Welcoming fall, and a look to the future

We’re only a week and a half into fall, but already it’s been a season of unexpected, roller-coaster temperatures, with record-tying heat alternating with unseasonably cool days and rain. Who knows what surprises are yet to come?

Master Gardeners welcomed in the new season this past Saturday, September 28 with Open Garden Day at our 0.4-acre demonstration garden.  It was a perfect day for members of the public to visit to our Learning Landscape; the weather was nearly ideal, and the attendance was absolutely fantastic. 

Visitors were able to enjoy the varied plantings in different sections of the garden, have their gardening questions answered by a team of dedicated Master Gardeners, select from a wide variety of informational handouts, enjoy complimentary garden tool sharpening, and much more. We thank every one of our guests for taking time out of their busy schedules to visit us, and we hope everyone left feeling inspired and happy, with new and helpful information in hand.

It was a rewarding and productive day for our San Joaquin Master Gardeners as well. A large and enthusiastic contingent of our newly trained 2019 program graduates joined veteran Master Gardeners in the morning’s activities. Together, we accomplished a thorough, top-to-bottom cleanup of the garden. Vegetable beds were rototilled and planted with fall crop seedlings; established trees and perennial plantings were carefully pruned; blooming perennials were deadheaded; irrigation systems were checked and prepared for cool weather; new plants were added to existing beds; and organic mulch was laid out for weed control, water conservation, and an attractive, refreshed appearance. 

I had the pleasure of talking with a few visitors while pruning perennials and shuttling buckets of green waste to the compost pile. It was heartwarming and encouraging to meet new people with a shared interest in sustainable landscaping practices; they all wanted to learn more about our many attractive and low-water-use plants, water-saving irrigation, and the effective use of long-blooming, pollinator-friendly plantings.

After the activities of the day were over, I had some quiet time to reflect on all the success of the event and to think about the positive impact each and every one of us can have on California’s environment. Little by little, day by day, every person has the power to help mitigate the habitat loss that has resulted from decades of human activity in our state—land clearing, industrial development, urban and suburban sprawl, and excessive pesticide use—and to prepare for the ever-increasing threat that climate change poses to native plant and animal communities and to human health and well-being.

Our individual efforts might be small, but collectively they can have a widespread and very substantial positive effect on our natural and human environments. We’re all an integral part of the web of life, and inseparable from it—we can’t survive on this planet if the ecosystems around us cease to function effectively. Native pollinators (myriad bees, beetles, hummingbirds, and other birds and insects) don’t just allow us to enjoy pretty flowers; without these small creatures, our food production systems and way of life would collapse. A diverse and healthy environment is truly the key our survival, and our actions can help ensure that it will be preserved for years and decades and centuries to come.

Consider for a moment some of the benefits of choosing and planting heat-loving, low-water-use, pollution-tolerant species of trees, shrubs, and other perennial plants. They can survive under challenging growing conditions, they minimize the use of precious water, they help to improve air and water quality, they reduce the amount of atmospheric carbon dioxide, they provide valuable shade and/or have a cooling effect that lowers the urban heat index, they provide shelter and nesting spaces for birds and other wildlife, and last but certainly not least, they beautify our public and private spaces.

Green lawns might look attractive, but they are high maintenance monocultures and virtually devoid of wildlife value. Replacing areas of unused lawn and barren pavement with small native gardens can have tremendous, collective environmental benefits. A key concept: Native plants are most beneficial for restoring the health of local ecosystems, since they evolved alongside our native pollinators in a system of co-dependency. 

Along those lines, I was excited to learn about a new Homegrown National Park program being initiated by the Sacramento Valley Chapter of the California Native Plant Society (CNPS). It’s “a community driven effort to regenerate the health of our ecosystems by encouraging homeowners, schools, businesses, governments, farmers, community groups, and you to plant local native plants to support the natural biodiversity of our region.”

The Homegrown National Park program will eventually use a multifaceted approach to facilitate environmental awareness and encourage planting of beneficial native plants. Those interested in helping reverse the severe decline in pollinator populations will soon be able to use access a wealth of resources on the program’s website. A landscape certification program is being developed to recognize public and private entities that install landscapes with a high percentage of pollinator-friendly native plants that bloom in succession throughout the year. Another program element still in development is a citizen-scientist program; this will enable participating Sacramento and Stockton area residents to report observations about native plant and wildlife interactions.

Here are a few local and national resources available to individuals and groups interested in sustainable, regionally appropriate landscaping information:

This fall, try using your garden to inspire positive change, help maintain biodiversity, and ensure the health of our dear Earth!

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website.

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Enjoy nature while in your garden.

Taking time to smell the roses can be extended to enjoying nature too as we go about tending our gardens. Recently, while in my garden, a beautiful black and blue dragonfly came along that I have never seen before. It landed several times on a steel stake, in fact, long enough that I could get my camera from the house and snap a fuzzy picture.

I looked online to see if I could discover its name. I am not sure that I got the right one, but the Widow Skimmer (Libellula luctuosa) seemed to fit. Several days later, a red dragonfly which I identified as a Flame Skimmer (Libellula saturata) came to the same steel stake to perch for my enjoyment. I find dragonflies to be beautiful and delicate with their colorful, lacy wings. Dragonflies are water breeders and since we have a slough about half mile from my home that likely fulfills this need.

I am also enjoying lots of Gulf Fritillary (Agraulis vanillai) in my garden. The next door neighbor has a passion flower bonanza where several passion vines grow rampantly. The Gulf Fritillary lays its eggs exclusively on passion vines as this is the only food source relied on for their young. Many other butterflies also have very specific plants to grow their caterpillar stage and such plants can be included in your pollinator gardens; see:

Today, I observed a Western Tiger Swallowtail (Papilio rutulus) butterfly, the first one I have seen this year. The caterpillar hosts may not be as abundant because they are: leaves of cottonwood and aspen (Populus), willows (Salix), wild cherry (Prunus), and ash (Fraxinus), but some of these are likely nearby.

I also have frequent visits of an unwanted cabbage butterfly (Peiris rapae). This species is native to Europe, Asia, and North Africa, It was accidentally introduced to Quebec, Canada around 1860 and thereafter this pest has spread rapidly throughout North America. It is distinctly white with two black dots on the wings of the female. Its caterpillar stage feeds on Brassicas or cole plants—cabbage, broccoli, Brussel sprouts and cauliflower.

Since I always have a cole crop planted in flats in the summer, it is a pest that I kill as frequently as possible using a butterfly net. I cast the net over them as they perch and as they fly up into the net I dispatch them to butterfly nirvana. I have already squished about 40 with no end of them in sight. So far the damage of the caterpillars to my cole crops has been minor.  However, if the infestation is heavy and damaging, control by spraying with Bacillus thurengeinsis, a bacterium that rots the caterpillars from the inside out. It is a good organic control see:

One butterfly I have seen in abundance lately is the Funereal Duskywing (Erynnis funeralis). It is similar in appearance to the Mourner Duskywing (Erynnis tristis). I had to resort to buying a Guide card for the Butterflies of Central and Northern California to make identification and I am still not positive I have it right. They are very close in appearance, both having a white fringe on the edge of the back wings and both share rather drab brown colors as well as dreary names.  

I also enjoy hummingbirds, mostly Anna’s (Calypte anna), that have been visiting my black and blue salvia, trumpet vine, hollyhocks and my neighbor’s Persian silk tree. I also enjoy seeing them visit my Salvia ‘Hotlips’ outside my office window along with shiny, black Carpenter Bees (Xylocopa spp­.).  Honeybees and sweat bees are also observed visiting my sunflowers. These bees are all important pollinators and friends to have in your garden. To keep Carpenter Bees from damaging your home follow these suggestions such as painting exposed wood and providing suitable nesting habitat. Please don’t resort to exterminations, see:

Not to be left out of my garden nature scene is the San Joaquin Fence Lizard (Sceloporus occidentalis). They are abundant around my flower and vegetable garden. They can be occasionally seen doing their push-ups on a low, rail garden fence or scurrying out of my way as I walk my garden paths. According to online sources they feed on a variety of insects, and other arthropods, including leaf hoppers, aphids, beetles, wasps, termites, ants, and spiders which makes them good garden companions. Don’t forget to take time to enjoy the nature in your garden and smell the roses too.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  

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Plan for spring bulbs and plant fall vegetables.

One of my gardening delights is to enjoy the beauty of Narcissus as they welcome spring.  As the Van Engelen, Inc, a bulb purveyor, puts it “Narcissi are the art and soul of spring” There are so many kinds of Narcissus and other spring bulbs it is sometimes hard to make the choices because it is not possible to plant them all. I am not inclined to purchase tulips as hybrid tulips often do not bloom a second time; but some of the wild species will repeat bloom and are worthy of consideration. 

Some Narcissus have long trumpets, and some have multiple flowers per stem such paperwhites, jonquils and Tezettas, which are also fragrant. If you want to prolong the ‘art and soul of spring,’ buy varieties that are early, middle and late season. There are not a lot of choices in color, but all are bright with white, pink, orange, and yellow components that standout. They also vary in size from miniatures 6-8 inches to large 18-20 inches tall. So many varieties and so little space!

In general, I like to select some landscape mixtures of varieties of long trumpet daffodils and short cupped ones and plant these beauties where I can. Fortunately I have a large area under an oak tree in my back yard that works well. Narcissus bulbs are ideal for our California climate. They grow well following fall and winter rains, bloom starting in early spring to brighten our gardens and then go dormant for our summer dry season. Hence they can be planted in areas that are not irrigated like the large area under my oak tree and they can come up and bloom before the tree leafs out fully.

I planted nearly 160 bulbs last year, but fell short of filling the area with bulbs, so I have ordered another 200 bulbs for this year and hope I can find enough room for all of them. You may wonder why I am writing an article on spring bulbs in September when spring seems far away. That’s because, if you want to enjoy the ‘art and soul of spring’ you must get busy and order bulbs now while you have lots of choices and plant them in October or November.  

However, I do remember one year buying some daffodils very late in the season on a closeout sale. I planted them very late in the fall, but they popped up and bloomed although perhaps a few weeks later than they would have had I planted them on time.

You can plant bulbs the slow, hard way with a trowel or you can purchase a bulb planting auger which, after attaching to a battery-powered drill, makes it easier to drill planting holes of the proper depth and size. I have used an auger for the last several plantings and it is convenient. For tips on growing Narcissi see:

It is important not to prune the foliage away from daffodils about 6 weeks past their bloom time. They need that foliage to produce and store energy for next year’s blooms.  If you don’t get blooms the following year this could be one cause; another is too little sun post-blooming or crowding of the bulbs after a few years of not being divided.  If crowded, mark the bulb sites and later dig and divide them in the fall and replant at the proper spacing. 

There are other more immediate gardening chores. It is time to think about fall vegetables. I usually plant onion seeds in flats in late August. I plant red onions for salads and a yellow, Spanish type of which there are several varieties for cooking. It is important to grow long-day-length or intermediate day-length onions in our area. Otherwise, they may not grow or mature properly. Long-day onions require 14 or more hours of light at the equinox, June 21, whereas intermediate-day onions require about 13-14 hours of sunlight. Short-day onions are planted further south where equinox day length is 12 hours or less. If you don’t start your own onion seedlings you can usually find them at local nurseries —usually after November 1.

Lettuce, turnips, carrots, mustard, collards, rutabagas, kale, chard can all be seed-planted now for fall harvest. I like to plant my lettuce in flats and then transplant so I can better control the spacing even though they can be direct seeded in the garden too. Happy gardening.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  

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Plan ahead for special fall garden events

This time of year is when gardeners begin to anticipate some relief from summer heat and cooler, more enjoyable outdoor time. The searing days of summer are a perfect time to plan landscape improvements, and fall is the best time to implement them.

The late fall months of October and November are especially ideal for re-landscaping. Cooler daytime temperatures mean that plants experience less shock when planting or transplanting, and still-warm soil and occasional rain showers encourage the growth of new roots before wintertime cold prompts plants to go dormant.

Take advantage of these upcoming events to buy special new plants, view well-designed gardens, learn some new landscaping concepts, connect with fellow plant lovers, or simply get outside in a beautiful setting. They are, in roughly chronological order:


California Native Plant Society (CNPS), Stockton subchapter outreach events

  • When: Thursday, September 5 and Thursday, October 3 from 4:30 to 8:00 p.m.
  • Where: Food Truck Fest, Oak Grove Regional Park, 4520 W. Eight Mile Road, Stockton
  • Website:

This small but dedicated group is committed to improving our local community through the use of durable, pollinator-friendly, water-wise native plants. Stockton CNPS also co-manages the native plant garden at Oak Grove Regional Park. Talk with Stockton CNPS volunteers at one of these two evening events, or visit their table at the Sandhill Crane Festival, November 2 and 3 at Hutchins Street Square in Lodi.


San Joaquin Master Gardener monthly gardening presentations

  • When: Second Monday of the month from 10:00 to 11:30 a.m.
  • Where: Lodi Library, 201 W. Locust Street, Lodi
  • Website:

Join local Master Gardeners for these free and informative classes! Our schedule for the remainder of the year is: September 9—Winter Vegetable Garden (with a bonus presentation on “Pickling Veggies” by San Joaquin County Master Food Preservers); October 14—Growing Succulents; November 11—Soil Health, Composting, Fertilizing; and December 9—Success with Houseplants. Class size is limited; please reserve your seat in advance by calling 209-953-6100.

The 2019 San Joaquin County Master Gardener/Master Food Preserver class schedule


Fair Oaks Horticulture Center Open Garden

This beautiful center is the demonstration garden for the UCCE Master Gardeners of Sacramento County. It’s divided into several different areas: a water-efficient landscape, a composting area, an irrigation display, and an edible garden with fruit trees, vegetables, herbs, and more. Open house mini-demonstrations will be held at 10 a.m.; topics include “Fall Planting and Plant Selections,” “Propagating Herbs,” and “How to Grow a Raisin.”


CNPS Fall Native Plant Sale (Sacramento Valley chapter)

This annual sale features a wide variety of California native perennials, shrubs, and trees; proceeds help support CNPS’s educational and conservation work.Anyone who joins CNPS or renews their membership at this sale receives a complimentary one-gallon plant from Elderberry Farms, the CNPS native plant nursery in Rancho Cordova.(Note: In past years, this was a two-day event; the sale will NOT be held on Sunday this year.)


San Joaquin Master Gardener Fall Open Garden Day

  • When: Saturday, September 28 from 9:00 a.m. to noon
  • Where: Robert J. Cabral Agricultural Center, 2101 E. Earhart Ave., Stockton
  • Website:

Join your local Master Gardener volunteers for a fun and informative day at the Learning Landscape demonstration garden! Wander the different sections of the garden—pollinator, Mediterranean, California native, edible, and foliage—and visit our many information booths. (More details to come in an upcoming article.) 

Note: Registration for our upcoming Smart Gardening Conference (January 25, 2020) will open in late October 2019. Visit our website to sign up for our free newsletter, which has event updates and informative articles on a wealth of garden-related topics.


UC Davis Arboretum Plant Sales

  • When: Saturday, September 28 from 9:00 a.m. to 11:00 a.m. (members only); Saturday, September 28 from 11:00 a.m. to 1:00 p.m. (public sale); Saturday, October 12 from 9:00 a.m. to 1:00 p.m. (public sale); Saturday, November 2 from 9:00 a.m. to 1:00 p.m. (public clearance sale)
  • Where: UC Davis Arboretum Teaching Nursery, Garrod Drive (across from the Veterinary School), UCD campus, Davis
  • Website:

These sales are very popular, so arrive early for the best selection and parking space! This one-acre nursery is packed with California natives and other pollinator-friendly plants, including those special ones designated as “Arboretum All-Stars.” Enjoy the on-site water-wise landscaping, seek guidance from gardening experts, and take advantage of educational displays. Make this a half- or full-day outing to allow time to visit the nearby Mary Wattis Brown Garden of California Native Plants and to wander the Arboretum pathways.


CNPS Fall Native Plant Sale (North San Joaquin Valley chapter)

  • When: Saturday, October 19 from 9:00 a.m. to 1:00 p.m. (tentative)
  • Where: Hughson Arboretum and Gardens, 2940 Euclid Ave., Hughson (NW corner of E. Whitmore Rd. and Euclid Ave.)
  • Website:       

This annual sale is held in cooperation with the Hughson Arboretum, whose mission is “to plant, maintain and make available to the public, native tree and plant species, trees of historic value, or other types of plant material to promote education about and appreciation of our natural environment….” The sale date is still tentative, so be sure to check the website for updates and confirmation.


CNPS Fall Native Plant Sale (Sierra Foothills chapter)

  • When: Saturday, October 19 from 9:00 a.m. to 1:00 p.m.
  • Where: Rocca Park, 18226 Main Street, Jamestown
  • Contact: Stephanie Garcia, Plant Sales Chair, (209) 586-3593 or      

Shop for shrubs and perennials that need minimal water during our hot summer months, and consult with knowledgeable “plant people.” Anyone who volunteers to help at this event can select favorite plants to buy before the sale opens to the public.


For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website:

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How to help your houseplants thrive

Houseplants. They bring beautiful greenery and a soothing outdoor presence to artificial interior environments. They convert the carbon dioxide we exhale into fresh oxygen. They help filter pollutants from sterile, indoor air. In other words, they’re simply miraculous!

Houseplants are typically grown for their foliage; their leaves can range from tiny to huge, lacy to leathery, rich green to variegated or multicolored. Some are grown for their spectacular and vibrantly colored flowers: orchids, African violets, bromeliads, kalanchoes, and more. Whatever your preference, indoor plants can be a great source of beauty and joy.

The best way to ensure a “green thumb” is to choose plants that will thrive in the conditions in the different areas of your home. Each nook or shelf or spot on the floor has its own special mix of sun exposure, light, air circulation, humidity, and temperature. Paying close attention to these conditions is the first step to success.

Houseplants are incredibly diverse. Some come from dry and sunny climates like ours; many others originate from areas with warm, humid, semi-shady tropical environments. It’s important to know the basic preferences of different indoor plants so that they can be given the best home.

The other key to success: learning how to maintain each of your chosen plants in a healthy condition. With houseplants’ great diversity comes a wide range of specific cultural needs, but here are some basic care guidelines. 

Snake Plant (Sansevieria trifasciata ‘Laurentii’). Photo by “Mokkie”, Wikimedia Commons,


Interestingly, overwatering is the main cause of houseplant death. Symptoms of overwatering—yellowing foliage, droopy appearance—often mimic those of under-watering, so it’s important to check soil moisture before breaking out the watering can. (On the other hand, severe lack of water is also very harmful to plants, and they might die if allowed to wilt repeatedly.)

One easy way to check for dry soil is to test its weight by lifting the entire pot. Properly moist soil will have some heft; too-dry soil won’t have much weight. A quick visual test can be effective, since moist soil is usually dark in appearance. You can also physically test soil moisture with a meter (the fancy method) or by probing with a finger (the low-tech method). If the soil is damp an inch or more below the surface, it’s probably moist enough. 

Frequent watering with small amounts of water is harmful to potted plants over the long term, because this leads to a build-up of salts and other minerals. It’s best to water plants less frequently and more thoroughly, until water passes through the pot’s drainage holes. Most potted plants benefit from an occasional thorough flushing. Plants growing in solid-bottomed pots without drainage holes must be watered cautiously, so that the soil doesn’t become waterlogged. 

Seasonal changes also affect the amount of water houseplants need. Most houseplants need more water while actively growing in spring, summer and early fall; water them more sparingly in the late fall and winter. 

The water itself is also important to consider. Some houseplants are highly sensitive to fluoridated water; others prefer lukewarm water instead of cold water. Never use softened water since it contains high levels of damaging salts. 


This is the second of the two most crucial elements for houseplant care. Depending on their natural environment, houseplants vary greatly in the amount and type of light they require. Some plants prefer direct sunlight, but this can literally be deadly for others.

Natural light from windows is best for indoor plants, but full-spectrum fluorescent lighting can be a good substitute in dark indoor areas. Some plants prefer only diffuse, indirect light from north- or east-facing windows; others can tolerate bright light or direct sunlight from south- and west-facing windows. Be sure to research the individual needs of your plants, because correct lighting is absolutely critical.


Purchase a high quality, commercially prepared, sterile potting mix that is suited to the plant(s) you own. For most tropical plants, an all-purpose potting mix with some organic matter will suffice. For plants that prefer acidic soil, use a specially labeled mix or one high in peat content. For succulents or cacti, use a product specifically labeled for them since it’s lightweight and fast draining and will dry out between waterings. Don’t fill pots with compost (which is a soil amendment) or garden soil (which is too dense).

Examine the soil and the rims of your pots for white, crusty-looking deposits; this indicates a build-up of harmful salts in the soil (from fertilizers or minerals in the water). To remedy this problem, scrub the pots and either replace the soil or thoroughly flush it with water. Most houseplants should be repotted with fresh soil every few years. Don’t reuse old soil, since it could be contaminated or nutrient poor.


With the exception of hot-environment succulents and cacti, houseplants generally don’t care for extra-dry indoor air. 

Moisture-loving tropical plants appreciate the humid environment in bathrooms or laundry rooms. Some plants appreciate a gently daily or semi-weekly leaf misting. Another way to increase humidity is to place potted indoor plants on trays filled with small pebbles and a small amount of water; the little rocks keep the pot bases above water, and the water evaporates slowly to give some extra moisture to the plants.


Daytime temperatures between 65 and 75 °F are acceptable for most houseplants, with slightly lower temperatures at nighttime. Keep plants away from the hot, drying drafts from heater vents and the cold blasts of winter air from doors, windows, and air conditioners.


All potted plants need fertilizer to replace lost soil nutrients. Plants that are fast-growing, frequently watered, or in quickly-draining soils should be fertilized regularly. Slow-release fertilizer pellets and water-soluble fertilizers are the easiest to use for indoor plants. Be sure to follow the label instructions to avoid misuse or harmful over-fertilizing, and avoid fertilizing plants in late fall and winter when their growth slows.

Pests and Diseases

You can minimize houseplant pest problems by using a few simple precautions. Before you purchase a plant, carefully inspect its leaves, stems, and flowers (if any), and also check the soil. Most common houseplant pests—mealybugs, scale insects, whiteflies, spider mites—will be visible to the naked eye. Also check for discolored, speckled, blotchy, or rotting leaves or any unusual growths on the soil; these can be signs of microscopic pests, fungal infections, or other diseases. Leave behind any plants that don’t pass these basic tests, because a bargain price isn’t worth the potential headache of spreading pests or pathogens throughout your home.

Keep in mind that stressed plants are more susceptible to attack by harmful organisms. Conscientious care of houseplants is the best way to prevent pest and disease problems.


Although these general care recommendations apply to the vast majority of houseplants, each species has its own specific cultural requirements. It’s best to consult a reputable book or other guide for specific advice about caring for your beloved plants. Some excellent references are: 

  • Houseplant books by well-known publishers such as Sunset and Ortho.
  • The House Plant Expert, by D. G. Hessayon
  • Sunset’s web page entitled, “The Ultimate Guide to Indoor Plants”
A glossy-leaved stalk of a “ZZ plant” (Photo by Kathy Ikeda)

To close, here are a few of my favorite, super-hardy, and easy care houseplants:

  • The ubiquitous spider plant (Chlorophytum comosum)
  • The “ZZ Plant” (Zamioculcas zamiifolia), with fleshy underground tubers and long sturdy stems graced with deep green, glossy leaves.
  • The snake plant (Sansevieria trifasciata), which grows as a cluster of narrow, stiff, upright leaves.

For gardening related questions, call the UC Master Gardener office at 209-953-6112, or visit our website.

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Complete the gardening experience by seed saving.

Saving seeds can be a fun thing to do and you can save seeds from plants that you find particularly satisfying. You can save a little money too. Some terms and definitions are in order to help understand the basics of seed saving.

Self-pollination occurs on plants with ‘perfect flowers’ where the transfer of pollen from the anther to the stigma of the same flower occurs on the same plant or a clone of the same plant. Self-pollinating plants are tomatoes, eggplant, peppers, lettuce, beans and peas. These are the easiest plants to save seeds from because they usually don’t cross-pollinate. However, there still exists a remote possibility of cross-pollination even with some of these plants.

Therefore it is recommended to keep lettuce and tomato varieties separated by at least 10 feet. Some older varieties of (heirloom) tomatoes have flowers that do not exclude cross-pollination because the style (female ovary part) is higher than the anthers (male parts) and thus could be pollinated by insects. Hence, it is safer to separate such tomatoes to the extent possible. Most of the time, cross-pollination does not occur for these plants. I have saved a lot of heirlooms planted next to each other without a problem, but the plants from seeds I saved from a ‘Big Rainbow’ turned out more to be more like ‘Little Rainbows’.  I always wondered if that one got cross-pollinated. Peppers are also vulnerable to cross-pollination and the hot pepper genes are dominant, so be cautious.

Open pollination occurs when wind, insects (pollinators like bees), or the gardener pollinates the flowers so they can set fruit and produce seeds. The seed of open-pollinated plants, when planted in subsequent years, will yield the same type of plant as its original or it can be said to be: ‘true to seed’. There will be some variation in plants from the seeds, but that is to be expected.

Heirloom plants are always open-pollinated or self-pollinated but they are a variety that has been around for at least 50 years.

Hybrid: A hybrid plant is a cross between two different types, or varieties, of plants. Growers hybridize a vegetable by isolating the most coveted traits from one variety and combining them with traits from another to form a totally new offspring. Seeds saved from a hybrid are unlikely to be true to the hybrid plant. However, some hybrids have been produced for such a long time that they can be propagated by seed saving. I attended a conference where a tomato breeder informed us that if the hybrid tomato seed costs less than 25 cents per seed, it is likely OK to save seeds from the hybrid as it has over several generations become a stable variety and will produce seeds like the parent. I suspect that ‘Early Girl’ tomato is one that qualifies as it has been around since 1975 and the cost is about 8 cents per seed. ‘Early Girl’ is sweet, tasty and early to produce.

Genetically Modified Organisms or GMO seeds: These are seeds that have been genetically manipulated in a laboratory with certain genes inserted. For example, corn and soybeans have been genetically modified so that the fields can be sprayed with glyphosate herbicide without harm to these plants. We often see ‘Non-GMO’ labels on advertising for garden seeds and in seed catalogs and seed packets. This is more of a reassuring marketing ploy than a real issue. There are no flower or vegetable seeds for the home gardeners that are GMO. The cost of producing GMO seeds for home gardeners is too high to be worth the effort.

Saving seeds that are not self-pollinating is a bit tricky. Plants of different varieties need to be separated by distance, isolated (caged to exclude insects) or have different bloom times. For more information on this, see: However, if you only have only one variety of cosmos, carrots, beets, chard, melon or other plants and you are far enough away from your neighbor’s gardens (or wild carrots) you can save seeds safely.

In the case of squash flowers you can isolate the female by bagging until it opens then hand pollinate by rubbing male flower parts on the female and then bagging again to exclude insects and tag it for seed saving. This is not a seed saving effort I have had the time or patience for. Whatever you decide to do in the seed saving department, it can be a satisfying culmination of the gardening experience. Happy seed saving.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:

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Gardening mistakes we sometimes make

Gardening is like most human endeavors prone to making errors. Last year I had a great harvest of strawberries from April to July. These were plants that I dug up at my old home the previous fall and moved them to my new home in Morada. I spaced the plants about 12 inches apart and they thrived. 

However, after harvest they thrived too well, sending out runners every which way and I made the mistake of not controlling them or starting a new patch. The bed became jam-packed with plants this past spring. It is recommended to prune off excess runners and I did try to thin them. I even potted up over 120 plants for our Linden Garden Club Plant Sale, but I was still not ruthless enough to thin them adequately. Consequently, I got very few strawberries this year as they were too crowded to be productive. 

In June, I dug out a few plants and spaced them 12 inches apart in a new bed to start over. I think I will get a good crop next spring, but after next year’s crop, I will replant them to a new bed right away after harvest and avoid the period of runner madness that I failed to address this past year.

Making this mistake with strawberries reminds me that I haven’t always thinned lettuce and carrot seedlings like I should. It is difficult to be ruthless, but that is often necessary to get good quality vegetables. I have also learned that planting lettuce in flats and transplanting them with the proper spacing avoids the thinning problem when seeding directly. Sometimes our mistakes turn out fortuitously well. This past year I had some old carrot seeds that I thought were not viable. I threw them out on a patch of compost-rich soil and ended up with the best carrot crop in years, whereas the ones I planted in nice neat rows didn’t germinate or were mowed down by snails.

I recently made a mistake when resetting my controller for watering. I thought I set it to water every two days for 45 minutes, but I found out a couple of days later that I had misread the dial and set it to water every 2 hours. I wasted water and I think some of my seeds didn’t come up because they were overwatered. ‘Pay attention’ is my guiding principle for the gardener but I obviously failed to uphold it.

All gardeners need to pay attention to garden’s soil type too. This is very basic knowledge to ascertain about your property. Sandy soils will require more frequent watering and more attention to fertilizing than heavy clay soils which hold moisture and are more fertile. All soils benefit from adding compost and incorporating compost is the best way to hold water longer in sandy soils and change the tight soil structure of clay soils to make them drain better and increase friability. Feed the soil compost and the soil will feed your plants. Most landscape plants need no fertilizer or inputs, but vegetable and flower plants often do. If you think you have soil-related problems, get a soil test and find out more about your soil type, organic matter, pH, and available nutrients. For a list of soil test laboratories, see:

Don’t make the mistake of neglecting weeding. Getting weeds when they are young and not producing seeds is critical to having fewer weeds in subsequent years. At my new home I would be very rich if I got a nickel for the thousands of spurge weeds that I removed from my gardens in the past two years. Recently, my friend, Dave, noticed that I had a plant in my flower bed that I had assumed was planted there for a reason. He identified it as Catchweed Bedstraw (Galium aparine) which has little prickles on the stems that give it a rough sandpaper feel.

I had no familiarity with this plant, but Dave recommended I get rid of it ASAP as it is nuisance weed at his homestead. Later I found it in several places in my landscape, so apparently it has gone to seed before. If not for Dave’s informing me, I would have left this plant in my landscape which would have been another mistake to add to my list. Although unknown to me, it is a widely distributed weed in California see:

For more on garden mistakes see:

Mistakes are the hard way we learn to become better, happier gardeners, but avoiding them is even better.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:

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Understanding the sun exposure needs of plants

As we enter the hottest parts of our San Joaquin summer, sun is a timely topic. 

Fall planting season will be here before we know it, and this is an excellent time for both experienced and budding landscapers to make plans for large-scale garden makeovers or the addition of a few new plants here and there. No matter what your future garden goals, it’s important to know about sun exposure and how it should affect your plant selection process.

Most gardeners are familiar with nursery plant tags and gardening reference books that use phrases such as “full sun” or “partial shade”—but what do those descriptions really mean? Let’s shed a little light on this important topic!

Sun versus shade

Over the eons, different plant species have evolved to adapt to the various environmental conditions specific to their location. Sun and light exposure is one important element of this adaptation, and we need to have an understanding of it to ensure that our plants thrive. General categories (which vary from source to source) are:

  • Full sun = 6 or more hours of direct sun. Vegetable plants and fruit trees need 8 to 10 hours of sun for best production. 
  • Light shade = 4 to 6 hours of direct sun. Many sun-loving plants can tolerate this condition, and plants preferring some shade can handle a bit of exposure to not-too-intense sunlight. 
  • Part(ial) shade/sun = 2 to 4 hours of direct sun. Some conditions that qualify: locations near or under trees with a light-filtering canopy; areas that received reflected light off buildings or fences; and areas that get several hours of morning sun but little to no afternoon sun.
  • Full shade= 2 hours or less of direct sun. Such areas include those covered mostly in shadow or that have dappled shade throughout the day.
  • Dense shade= No direct sun and little indirect sun. This includes areas under dense evergreen trees or shrubs, under overhangs, or in narrow, sheltered pathways. Growing conditions in such locations are difficult because they can also be very dry or because there is lots of competition for root space. Attractive mulches, pavers, or garden art are good solutions for such plant-unfriendly spaces.

Keep in mind that even dense shade does not mean a completely dark location, because all plants need some light to grow.

Plant tags will sometimes list more than one of these ratings. What does that mean? The first term listed is the plant’s preferred condition, while the secondary term is a condition the plant can also tolerate. For example, a plant with a tag saying “sun to part shade” would grow best in a sunny location but could still handle some shade. 

These ratings are sometimes qualified even further. One example from the Sunset Western Garden Book is the plant known as beach strawberry (Fragaria chiloensis).The sun exposure notation for this plant says, “afternoon shade in hottest climates,” and that description is very accurate. This ornamental groundcover is growing in one part of my yard to provide small, seedy snacks for chickens, and over the years it has spread by runners from the lightly shaded location where it was planted to an area that receives full afternoon sun in the summer. The adventurous, spreading parts of the plant look severely stressed at this time of year, whereas the parts shielded from afternoon sun are still lush and happy.

Sun-scorched leaves on a beach strawberry plant, Fragaria chiloensis (Photo by Kathy Ikeda)

That’s intense

Light intensity is another important consideration. It’s a relatively simple concept: morning sunlight is gentler and less intense than the hot, harsh afternoon sun. Plants that need some shade will do better if they’re exposed to sun earlier in the day and protected from sun in the latter hours of the day.

Direct sunlight, where the sun’s rays fall directly on a plant’s leaves, is also very different than indirect sunlight, where a plant receives light reflected from other sources. Some plants, particularly houseplants native to shady tropical forest environments—Philodendron, Calathea, Plectranthus, Schefflera, and more—can be quickly and severely damaged by direct sun exposure on their sensitive leaves.

Location, location, location

Climate zones (either those defined by the USDA or Sunset) are an important consideration when evaluating sun exposure. If you purchase a plant from an out-of-area nursery or mail-order source, carefully investigate how it will respond to our local growing conditions. A plant might be rated as suitable for “full sun” by a grower located in the Bay Area or states in the northern U.S., but that rating often won’t translate well to our harsher summer environment.

Microclimates—the often-profound differences in climate conditions that can exist in a landscape—are also a key factor. Large trees, fences, walls, house orientations, and the seasons all affect the sun exposure that each area of a garden receives. A part of the yard that’s shady in the winter might not be in the summer as the angle of the sun changes. Plants in locations with a southern or western exposure or those near heat-reflecting walls or paving are more susceptible to light- or heat-related damage. Plants under a deciduous tree will receive more direct sun in the winter when the tree is bare than they do in the summer when the tree is leafed out. Pay close attention to these factors and make note of them when developing a planting plan.

I’ll use one difficult part of my own backyard to illustrate this concept. Due to the ever-changing angle of the sun throughout the year, the footprint of my house, and the location of overhangs, one small dry garden bed receives lots of full summer sun during the hottest time of year—including intense afternoon heat reflected off an adjacent stucco wall—but it’s in full shade all day during the coldest winter months. I haven’t found a perennial plant that’s happy with such extremes of sun exposure and growing conditions, so this little patch of soil is where I’ve resigned myself to “crop rotation,” growing heat-and-sun-loving herbs in the summer and shade-loving annuals in the winter.

As always, gardening is a matter of experimentation and trial-and-error! If a plant is scorching/bleaching or failing to thrive because of improper sun or shade exposure (or any other site-related condition), try transplanting it to another location that might be more suitable, and watch to see how it responds to its new home.

Some helpful resources that include sun exposure guidance/considerations are:

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or visit our website.

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How to use the Master Gardener Help Desk

Has your garden been invaded by an insect pest, and you have no idea what it is or how to safely banish it from your yard? Is one of your beloved and formerly thriving plants suddenly looking stressed and unhealthy, and you have no clue what’s wrong? Is your garden suddenly plagued by unfamiliar and tenacious weeds, and you want to learn what they are and the best way to remove and prevent them?

The San Joaquin Master Gardener Program, administered by the University of California Cooperative Extension (UCCE), has a Help Desk service specifically intended to help answer these types of questions. Here’s a brief summary of our contact information:

Master Gardener Help Desk
Hours: 9:00 a.m. to noon, Monday through Thursday 
Address: Robert J. Cabral Agricultural Center, 2101 E. Earhart Blvd., Suite 200, Stockton
Phone: (209) 953-6112

When you contact the Help Desk, remember that it might take a few days or even weeks to properly diagnose your particular plant and/or pest problem. Sometimes the cause, effect, and solution can be fairly easy to determine; at other times, Master Gardener volunteers might need to enlist the help of trained scientists (plant pathologists, entomologists, etc.) to correctly diagnose a condition or identify a pest. Remember that accurately determining the problem is the key to finding the appropriate and effective solution.

Plant damage and disorders have either biotic or abiotic origins. Biotic problems are those caused by living organisms: small mammals; chewing or sucking insects; snails and slugs; harmful fungi, bacteria, or viruses; and more. Abiotic problems arise from environmental factors such as pesticide toxicity, nutrient deficiencies, drought stress, overwatering, air pollution, mineral imbalances, excess or insufficient sun exposure, and so on. 

It’s most helpful for Help Desk volunteers if our “customers” initially visit in person and deliver actual plant and/or insect specimens. Diseases, disorders, and pests are often specific to particular plant species, so the first step in solving your garden-related problem is to accurately identify the affected plant. Having an actual sample or two in hand makes that process, and the eventual diagnosis, much easier. Later follow-up can be by email or phone.

How to submit plant samples:

  • Use sharp, sterile pruning tools to avoid spreading any potential diseases. 
  • If possible, trim off an affected piece of plant large enough to include leaves, stems, flowers, fruit, and even roots, if that could be where problems are occurring. This aids in plant identification and diagnosis.
  • For comparison’s sake, also trim and bring in a healthy portion of the plant.
  • Bring plant samples to the office as soon as possible after collecting them. Fresh samples are absolutely necessary for accurate diagnosis; old, dried, or rotten material can’t be used.
  • Place plant samples in sealable plastic bags large enough to accommodate them without damage. (This not only protects the sample, it also prevents accidental spread of potential plant pathogens.)
  • Write your name, contact information, and date and location of collection on each bag.
  • Refrigerate plant samples for a short time if immediate delivery to the Help Desk isn’t possible.
  • If it’s not physically possible to bring a sample—for instance, if the specimen is too large —please take a series of clear photos of the plant from different angles, ranging from a picture of the entire plant/tree to close-ups of the problem area.

How to submit insect samples:

  • Collect one or more insects using a method that won’t damage them. Squashed specimens or insects with missing body parts can’t be identified.
  • Place the insect(s) in a tightly sealable clear jar or container. (Plastic bags aren’t suitable, and a tight seal is necessary to prevent unintentional release of pests into new areas.)
  • If possible, preserve the insect by covering it with clear rubbing alcohol.
  • Write your name, contact information, and date and location of collection on the outside of each container.
  • Deliver your insect specimen(s) to the Help Desk as soon as possible; they can be refrigerated for a few days if necessary.
Master Gardener Win Rogers at the Help Desk window in the Robert J. Cabral Agricultural Center. (Photo courtesy of Candy Walker)

We recognize that busy lives and work schedules prevent many people from visiting the Help Desk in person, which is why there are also options for emailing or calling our office. Email is by far the more effective of these two, because plant/pest photographs can be submitted electronically and because it gives both our office and our patrons a written record of the diagnosis process. If you call the Help Desk after hours, please leave a voicemail with your name, the date and time of your call, the city where you live, and your phone number and email address.

No matter what method you use to contact the Help Desk—in person visit, email, or phone call—be prepared to answer a long list of questions from our volunteers. Plant problems are often caused by a combination of factors, so our investigative work must necessarily cover a whole spectrum of issues. If you already know the exact ID of your plant, that’s a good start. We’ll also ask you to tell us, to the best of your abilities, what cultural care your plant has been receiving: timing and frequency of watering, fertilizer use, pesticide/herbicide exposure, daily sun/shade, pruning, etc. Environmental factors can lead to stressed plants, and stressed plants are more susceptible to diseases and pests, so this is all relevant data collection.

The Help Desk is staffed entirely by Master Gardener volunteers, with either one or two people present in the office during each weekday shift. Every attempt is made to keep the office staffed on a regular basis; however, it’s best to call ahead to ensure that someone will be available if you intend to visit the office in person.

Although Master Gardeners can’t make home visits or provide physical gardening assistance to individuals, our Help Desk volunteers work hard to provide San Joaquin County residents with a valuable public service, and we hope you’ll take advantage of it when needed! 

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