It’s time for bare root planting

Have you been thinking of adding a fruit tree or two, some roses, or other productive plants to your garden? This is the perfect time for plants that are sold in “bare root” form.

Most deciduous fruit and nut trees are available bare root: almonds, apples, apricots, cherries, nectarines, peaches, pears, persimmons, plums, walnuts, and more. Other ornamental shrubs, fruiting vines, and perennial edibles are also available bare root: artichokes, asparagus, cane berries (blueberries, blackberries, raspberries), grapes, kiwis, roses, etc.

Commercial growers dig these trees and plants from the ground in late December when they’re dormant. The soil is washed off the roots, then the plants are bundled or packaged and shipped to local nurseries without pots. The roots are covered with a loose, moisture-retaining material such as peat moss, sawdust, fine wood shavings, or shredded paper to keep them from drying out.

The bare root season is short, lasting only from January through mid-February, so take advantage of this opportunity before it’s too late! (If you miss local bare root offerings, you might still find some plants by mail order through growers in colder climate areas of the country.)

There are several advantages to buying bare root plants:

  • Optimal Growth.  Bare root plants acclimate more readily to new soil conditions than do actively growing plants. Also, since they have no leaves or flowers to maintain, they can put all their energy into developing a strong root system after planting.
  • Low Weight.Because there is no heavy pot filled with soil, moving the plants from field to store to planting location is much easier.
  • Wide Selection. The variety of fruit trees and roses available now is much greater than during the warmer months of the year. Shop soon for the best selection.
  • Great Price.It’s much more efficient for growers to harvest, store, and ship plants in bare root form, and there is no supplemental cost for pots, planting soil, or the labor involved in potting. Therefore, it’s less expensive to get a bare root plant to market, and those cost savings are passed along to the consumer.

Before buying a bare root plant, inspect the root system carefully. Look for a healthy root system with an abundance of well-branched feeder roots. Avoid plants with dry and shriveled roots, rotting roots, badly kinked or broken roots, or roots that circle and girdle the base of the plant. If the roots are covered with plastic, examine any visible roots and make sure that the packaging is intact to prevent dried out roots.

Check the upper part of the plant too. The bark should be undamaged, and the trunk or branch structure should be sound. Rose plants should have at least three healthy canes. Some herbaceous (non-woody) bare root plants, such as artichokes and asparagus, are sold as funny-looking root balls without any top growth; don’t worry, new leaves will emerge a few weeks after planting.

Another consideration for stone fruit trees (with a single, large, hard seed) and pome fruit trees (with a core of small seeds, such as apples, pears, quince) is chill hours. These trees need a minimum number of hours below 45°F in order to break dormancy and achieve good flower formation and fruit set. In San Joaquin County, our average annual chill hours are about 1100 (data from 2013-2017), so check the plant label to make sure you buy appropriately.

It’s usually better to purchase from reputable nurseries with knowledgeable staff than from discount stores and big box chains. Unscrupulous retailers have been known to remove leaves from bare root plants so that they looked dormant when they aren’t. Emerging leaf buds or flowers mean that plants have come out of dormancy, and picking off their new growth robs the awakening plants of valuable energy.

Bare root plants should be planted in their permanent location as soon as possible after purchase, but rainy weather or busy schedules can interfere with the best of intentions. If immediate planting isn’t possible, you’ll need to keep the roots of your chosen plants from drying out or freezing. Loosely wrap the rootballs with wet burlap or newspaper, or place them in a pot full of fine, moist, sawdust or compost. Keep the plants outdoors in a cool location; avoid warm, bright places because they might think it’s spring and come out of dormancy.

Bare root fruit trees with opaque plastic packaging that prevents root inspection. These trees were improperly displayed in a warm, bright, interior location. (Photo © Kathy Ikeda)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The best way to temporarily store bare root trees is by a process known as “heeling in.” Dig a shallow V-shaped trench in a protected, shady area of your yard. Remove any packaging from around the roots, then place the rootball into the trench so that it is entirely below ground, with the tree lying down against the side of but outside the trench. Cover the rootball with loose soil or sawdust, then water it lightly but frequently to keep it moist, not saturated. A wheelbarrow in the garage works well as a temporary storage “trench” too.

When you’re ready to put your bare root plants in the ground, choose a sunny location with well-drained soil. Prune out any damaged roots. Dig shallow holes only as deep as the rootballs, and 2 to 3 times as wide. While you’re digging, dunk the rootballs in a bucket of water to rehydrate them. (Don’t leave roots submerged for more than a few hours, because they need oxygen to survive.)

Trees should be planted with the graft union above the soil level and the crown or root flare at ground level; if planted too low, the crown will rot, and if too high, the rootball will dry out. Other bare root perennials should be planted on top of a cone of packed soil within the planting hole, with the roots spread out over the cone and the crown of the plant at ground level. Once the plants are in place, backfill the holes with native soil, gently tamp it down to eliminate any air pockets around the roots, then water.

There are many important considerations when planting a bare root tree or perennial, far too many to cover in detail here. Consult these excellent resources before you buy and plant your bare root treasures:

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

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Proper pruning of ornamental grasses

I have to admit, this article is about one of my pet peeves, plant butchering. I hope to educate homeowners and commercial landscapers about how the specific growth habits of different plants should dictate the appropriate pruning methods.

If you remember only one rule from this article, it should be this: some plants should NOT be sheared into unnatural balls or boxes!

This caveat especially applies to tall grass species and similar plants. Their leaves are showy, and if they’re chopped halfway off the attractive form of the plants will be ruined permanently or for many years to come. If grasses are “shaped” like hedges, the result is unsightly, ragged balls of half-length leaves from which the points of longer, newly emerged leaves stick out, looking like a horrible haircut.

Ornamental grasses and other plants with a similar appearance have characteristically long, narrow, strap-like leaves, and they’re frequently used as focal points in a landscape. Depending on the species, their foliage can be stiffly upright, gracefully arching, or tufted. They don’t have branches with leaves scattered along their length; instead, their leaves all emerge like a fountain from a central, ground level clump or “crown.” Their leaf buds are at the root-shoot junction at or near the soil level.

So how should these plants be properly maintained? Let’s start with the grasses.

Ornamental grasses can be grouped into two categories: warm season and cool season.  Each has different pruning needs.

Warm season ornamental grasses

Warm-season grasses grow best at temperature between 80 and 95°F. They grow robustly during spring and summer, flower in fall, and go dormant from late fall through early spring. Some commonly planted decorative species of warm season grass include Deergrass (Muhlenbergia rigens), Blue Grama (Bouteloua gracilis), Fountaingrass (Pennisetumspecies), and Maiden Grass (Miscanthus sinensis).

As a general rule, warm season grasses need a pruning only once a year or less. Oftentimes, they can be “combed” with gloved hands or with a small rake to remove dead leaves and neaten their appearance, without the need for severe pruning. When grooming the plants, start at the base then pull upward to remove old growth. If necessary, the clumps can be renewed by cutting them down to a height of 2 to 4 inches (not flush to the ground, to protect the crowns).

The best time to cut back warm season grasses is in late winter or very early spring, just before fresh leaves begin to emerge. (The exact timing of new growth depends on climate and precipitation.) The exception to this seasonal trimming rule is if you live in a fire-prone area; in this instance, cut back dried grass clumps in the fall, and protect their tender crowns with a layer of loose organic mulch.

Warm season grasses are best undisturbed through winter. Their dried flowering stalks, seedheads, and leaves change color to subtle shades of golden-brown, tan, and white during dormancy, adding a decorative touch and visual interest to the winter garden. The old leaves also protect the tender crown of the plant from frost damage, and they provide shelter for birds and beneficial insects.

Poorly pruned deergrass, with new leaves emerging from improperly shaped balls, contrasted with a beautifully maintained deergrass specimen. (Photos © Kathy Ikeda)

 

 

 

 

 

 

 

 

 

 

 

Cool season ornamental grasses

Cool season grasses favor temperatures between 60 and 75°F. They begin new growth as temperatures drop in the fall, and they prefer more moisture than warm season grasses. Many cool season grasses flower in spring and stop sending out new growth in summer. In our mild climate they grow year round, although their growth slows significantly in heat. Some common ornamental cool season grasses include Feather Reed Grass (Calamagrostis x acutifolia), Blue Fescue (Festuca glauca), and Blue Oat Grass (Helictotrichon sempervirens).

Periodic upkeep to remove dead leaves and spent seedheads is sufficient to keep these grasses attractive for many years, without trimming/pruning. Use the same grooming method as with warm season grasses.

Cool season grasses often don’t need cutting back unless the foliage is damaged or dominated by old leaves. If it’s necessary to renew these grasses, cut them down by about 2/3 before the fall growth spurt, or early in summer if fire danger is a consideration. Trimming cool season grasses too severely or frequently or at the wrong time of year — such as during peak fall and winter growth or during severe cold weather — will stress the plants and make them more susceptible to disease or frost damage. Once new growth fills in, the older, shortened leaves can be selectively cut out with pruners to improve appearance if needed.

Cool season grasses are also pretty in winter, when cold temperatures often leave their foliage tinged with hues of bronze, purple, red, or gold.

Some final notes

Make sure your pruning tools are clean and sharp to prevent disease and ragged cuts. Hand pruners work well for small grass species, but if you have large grass clumps to cut back, use manual hedge shears, electric hedge trimmers, or a weed trimmer fitted with a blade attachment.

One useful trick is to bind the leaves of each grass clump together before pruning; this keeps them out of the way and makes clean up easy. If you use natural jute twine instead of man-made materials, the entire bundles can be composted or put in green waste bins.

Some excellent sources of information on ornamental grasses and their care are:

  • “The Encyclopedia of Ornamental Grasses” by John Greenlee
  • Pruning Ornamental Grasses,” an online article by the UC Master Gardeners of Sonoma County
  • A short YouTube video entitled “Pruning Ornamental Grasses” by the University of Illinois Extension

Next month, we’ll take a look at how to properly maintain grass-like plants.

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

 

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Tree Peonies and herbaceous peonies are long term plants.

A tree peony in full bloom is dazzling.

Another tree peony that will brighten the garden.

There are quite a few plants that I miss after downsizing. I have previously mentioned camellias and several productive citrus trees are missed too. Also missing at my new home are tree peonies (Paeonia suffructicosa) and herbaceous peonies (Paeonia lactiflora). The tree peonies were pretty special. When I first moved to my former home in 1976, I found an old tree peony that was in a bad spot, so I moved it to a better location and enjoyed its dark red blooms for 40 years as well as those of others that I added to the peony patch.

Tree peonies are magnificent, long-lived woody shrubs that enhance any gardener’s joy. They provide structure in the garden and the foliage is bronze in early spring, dark green in summer and bronze to purple in the fall. They can reach 4 to 6 feet in height and are capable of bearing fragrant flowers up to ten inches in diameter. They are the most popular flower in China and once were grown exclusively for the emperor.

Many tree peonies for sale are grafted clones of popular varieties. Tree peonies can be started from seed, but with difficulty and I have never mastered the technique involved although I did have one grow from self-seeding. Many peonies purveyors often sell tree peony seeds in addition to plants, so it can be done. I had a good friend and neighbor, John, who mastered growing them from seeds. He planted seeds annually and when they started to bloom, which occurred about 3 years later, he would sell them. John never knew what colors or kind of flowers the seeds would produce until the first bloom. I was an eager buyer and he once gave me one that I always cherished in his memory as he is no longer with us.

The bees love these tree peonies along with gardeners.

I planted a patch of my garden with several tree peonies and got to enjoy their transient beauty each spring. Rain and wind are the enemies of the large vulnerable blooms, so I always wanted good weather during the bloom time which is relatively short. Fortunately, I took lots of pictures so I can still enjoy them in my old age.

Here are some tips on growing tree peonies. Some afternoon shade and dappled shade is best, but they can handle full sun. A well-drained, rich soil that is neutral to slightly alkaline is preferred; so most local soils will work. Fertilizing can be a top dressing in the spring with an inch of compost or aged manure. Some shelter from wind is advisable to protect blooms in the spring and where they will be protected against drying winds. Tree Peonies are very drought tolerant once established and should not be overwatered.

Pruning is fairly minimal and should be done in February when buds start to swell. Dead shoots should come off and remove dead material back to lower live buds. Often there is die-back of last year’s flowering shoot, hence the need to prune back to live buds. Also prune out any wayward shoots that are horizontal and not upright.

Companion plants that work well with tree peonies are snowdrop bulbs (Leucojem aestivum), Spanish bluebells (Hyacinthoides hispanica), Scilla bulbs (Scilla siberica) and perhaps some early blooming Narcissus around the edges of the tree peony patch such as paperwhites or small daffodils. Heucheras, violets, and Hellebores will also work to provide variety.  I planted a crepe myrtle in the middle of my tree peonies which provided color from summer to fall.

Herbaceous peonies make a nice fragrant border to this patio.

At the old homestead, there was also a row of Herbaceous Peonies. I enjoyed their large pink blossoms every spring. Herbaceous peonies require a cool winter climate, well drained, loamy soil, good air circulation and sunshine. They are best planted in the fall so they can develop the root system and storage of nutrients for spring growth. They are deer proof as are tree peonies, so both are good candidate for foothill gardens. These are long-lived perennials and can bloom with single or double flowers in colors from pure white to deep red. The cut flowers are often fragrant and will last for a week if cut at full bud stage. Unlike tree peonies, herbaceous peonies are cut to the ground in the winter or early spring. For a look at companion plants to use with herbaceous peonies see: http://www.enchantedgardensdesign.com/blog/2018/6/5/peony-partners.

Intersectional or Itoh peonies are hybrids of tree peonies and herbaceous peonies. They are short, strong-stemmed, require no support and make excellent cut flowers. They bloom about 3 weeks after herbaceous peonies bloom. Hybridization has resulted in gold and yellow blooms not seen in herbaceous peonies. The Itoh peonies are pruned to the ground each winter like herbaceous peonies. So—be a happy gardener and enjoy glorious peonies.

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:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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Time is nigh for pruning roses.

'Love and Peace' is a gorgeous hybrid tea rose which can be the reward for thoughtful rose pruning and care

Generally modern roses are best pruned in January when they are as dormant as they will likely get in California. I always think of New Year’s Day as the time to start. The timing and amount of material removed depends on which roses you have in your garden. There is no reason to be anxious about pruning roses. It is not easy to kill a rose, especially by pruning and often gardeners don’t prune as severely as may be desirable. Learning to prune roses is best done with a hands-on approach with an instructor to guide you, but that isn’t always possible, so I will do my best to be an instructor from afar.

Before starting, it is useful to understand some history and terms. Remontane is another term for repeat blooming. Remontane roses were created from a Chinese rose, Rosa chinensis that was imported to Europe from China in 1759. Before this date all European roses only bloomed once. Modern Roses were developed after the first hybrid tea, ‘La France’, was created in 1867.

The bud union is the point from which new canes grow and is the part of the plant grafted to the rootstock. Suckers are canes that come from rootstock below the bud union.  However, some roses are now propagated on their own rootstocks. The shank is the area of the root stock between the bud union and the roots. The bud eye is the bud that lies just above each leaf origin. Prickles are those thorn-like parts that we avoid by wearing gauntlet gloves when pruning. They are prickles not thorns though even rosarians often call them thorns. For more rose glossary terms and a useful rosarian website see: http://temeculavalleyrosesociety.org/rose-glossary.html#onceblooming.

Pruning Hybrid Tea, Floribunda, Grandiflora Roses and MiniaturesThese are all modern roses, repeat bloomers and have similar pruning methods. Miniature roses are basically miniature versions of hybrid tea roses and can be pruned similarly. Roses may have only 2 to 4 canes when purchased. However, as they grow they develop more canes and the younger canes should be left, provided they are large and robust. Older canes in decline with little new, strong growth in the past year should be removed.

 

There is no set number of canes to leave—it depends on the vigor of the rose. Pruning a rose increases its vigor so if your rose has a lot of vigor, prune leaving more canes and longer canes; if less vigorous, prune harder. Canes will also need to be shortened by half of their length and to 3/8 inch above an outside facing bud eye to keep the center open and vase- like.

It is also important to examine the cane bark for damage from disease and remove parts so damaged; also if the canes’ centers are brown and dead looking then remove segments until healthy tissue is evident. Also remove any suckers coming up from the rootstock as they will take away resources from your grafted rose and eventually take over. Any wimpy growth less than pencil size should also be removed.

Shrub Roses, Old Garden Roses do not need to be pruned as severely as the above roses. Height may be reduced and older declining canes should be removed using the “one-third” method. Each year a third of the older canes are removed as well as dead or diseased canes. If the old garden roses are once blooming types, such as Galica, Centifolia, Alba, Moss or Damask, a majority of pruning is done after bloom.

Climbers: Climbers have their own pruning needs. Roses that bloom only once a season are pruned just after the bloom period ends; strong new growth produced after bloom will bear flowers the following spring. Lady Bank’s (Rosa banksiae ‘Lutea’), a climbing rose, is an example of this type.

Many climbing roses bloom twice, first on the older branches and then on the growth of the current season. In the winter, remove

Goatskin gauntlet gloves were a gift to me that I cherish as they provide vital protection for rose pruning

diseased, injured, crossing or spindly branches, cutting them away flush with the cane from which they emerge. Older, woody canes can be removed as well and canes that have outgrown their support should be trimmed to put them back inbounds.

Climbing roses will need to be fastened to a fence, wall or trellis or support with tape or ties. Select the best canes and trim back sufficiently to allow for new growth to be supported. Lateral shoots are shortened to 2 to 5 buds by cutting at 3/8 inch above the highest bud. Climbing roses will produce more flowers if the canes are positioned somewhat horizontally to the extent possible.

For more information on rose pruning see: http://farmerfred.com/rosepruning.htm and for videos on pruning roses Fine Gardening has several at: https://www.finegardening.com/article/pruning-climbing-roses.  Here’s to a good start on next year’s roses—happy pruning.

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:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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Orchids are easier than you think

Phaelaonopsis orchids are offered at many grocery outlets.

I am sure that gardeners reading this might be a bit skeptical of orchids being easy. Full disclosure, some are very fussy, but even the easy ones can be killed if not properly tended. Grocery stores often feature orchids in their flower offerings and they are so gorgeous it is hard to resist buying one. They are cheaper to buy alive than the artificial silk one often offered in many stores and online. Although silk ones are definitely hard to kill, the living ones are preferred if you are a gardener.

Orchids are a large family of 22,000 or 110,000 species depending on your source, but there are a lot of them and many hybrids as well. Hence, there is no end of possibilities for the avid collector and I suspect that orchid collecting can be addictive for the orchid enthusiast. If you are an enthusiast, you can join others; see the San Joaquin Orchid Society on Facebook. I have yielded several times to their beauty, but unfortunately my few orchids all succumbed last winter because I failed to protect from freeze damage following my downsizing move.

Recently, the Linden Garden Club had a guess speaker on orchids and I learned more about caring for orchids. Our speaker, from Modesto, was the president of the International Orchid Society, so definitely an expert. One thing I learned was to keep most orchids out of direct sun. The orchid that we see for sale at stores is Phalaenopsis or hybrids thereof. This is a long blooming orchid which is best kept in bright shade as one would do with African violets. Another thing she addressed was the use of ice cubes to slowly water orchids. Orchids are mostly tropical plants so ice watering is a very bad idea.

In nature, orchids don’t grow in soil, but are epiphytes that live in rain forest trees. You can replicate this kind of environment by using orchid bark or a moss potting mix. Orchid bark potting material or moss based material is readily purchased at nurseries. The orchid bark contains fir bark and charcoal. The orchids you purchase are often planted in a moss mixture.

Either of these materials will provide the quick drainage and plentiful air pockets that orchid roots require. In the case of Phalaenopsis, it is best to use a medium coarse bark mix if available. Orchid bark decomposes within 18 months to 2 years, depending on watering and fertilizing practices (wetter and more fertilizer means shorter bark life). Repotting should be done before major decomposition creates anaerobic conditions causing root rot.

Phalaenopsisis a long bloomer and after blooming it is time to get it ready for a new season of blooms by repotting to give the

Phaelaonosis orchid I recently purchased with 3 stems of flowers, a good find.

roots room to grow. Often the ones purchased are crowded into a small plastic pot inside a terra cotta or ceramic pot. The orchid should be gently removed from the plastic pot and any brown-colored, dead roots removed by cutting with scissors or pruners along with the dead bloom stem. Soaking the roots in water can help remove old potting material.  If roots were crowded go to a larger pot, but not more than 2 inches larger than the current one. Do not tightly pack the potting material because an orchid’s roots need breathing room. Repotting should be done every 2-3 years and best to stick to plastic or terra cotta pots with drainage holes.

What other conditions will be optimal for my orchid?  Keep the orchid in a spot that gets a lot of light but is out of direct sunlight. If the orchid isn’t getting enough light, it may not bloom again. Warmer temperatures are best from 70 to 85 F. Humidity is often hard to control in the home. You can either use a humidifier in the orchid room or place the plant on a saucer filled with pebbles and water (with the pot’s bottom not in the water). The evaporation will add moisture to the air. You can also mist-spray the plant’s leaves a couple of times a week. For more good information on orchids: http://www.aboutorchids.com/.

Water deeply until excess water runs out of the drainage holes. Phalaenopsis should be watered thoroughly about once every 14-20 days; more than that could be too much. Allow the potting medium to dry out between watering to avoid root rot and killing the orchid. Balanced commercial orchid fertilizers (20-20-20) will keep your plant growing. Eventually, after new leaves have grown in, a stem will start to grow and as it elongates, be sure to tie it gently to a stake you stick into the pot. You can save the bamboo stake and ties your orchid came with and use them again— so enjoy happy orchid growing.

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:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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Rain gardens

Now that wet weather has finally arrived, it seems a good time to write something about those little drops falling from the sky.

You might ask, “What are rain gardens?” One writer has very aptly described them as gardens that “encompass all possible elements that can be used to capture, channel, divert and make the most of the rain and snow that fall on a property.” The goal is to create a landscape that keeps water onsite. Rain gardens are not ponds, however; when properly designed, they allow water to percolate into the soil within one to three days.

Why is water retention important? Consider this: urban/suburban development has covered vast areas of land with paved surfaces and buildings, preventing any precipitation from reaching the soil underneath. The moisture that used to soak into the soil now drains away. It can no longer nurture the roots of trees and others plants, benefit soil-dwelling organisms, or help sustain natural underground reservoirs of water.

Most city rainfall travels from sky to impermeable surface to storm drain.  Rain from waterproof roofs is collected in rain gutters, then it travels through drainpipes to street gutters. Rain that falls on parking lots, streets, and sidewalks flows into storm drains without ever touching bare soil. Those storm drains connect to conveyance systems that carry untreated water into local waterways. Street pollutants (oil, gas, asphalt leachates, antifreeze, and more), loose trash, and many other harmful substances are thus carried out to local rivers and the ocean. That sobering fact is why many of our local storm drain inlets are painted with notices that say, “No Dumping. Flows to Delta.” Even the water that drains from lawns can be contaminated with excess fertilizer, pesticides, and pet waste. Untreated, polluted runoff fouls natural bodies of water, harms aquatic wildlife and vegetation, and is a main cause of toxic algae blooms.

Rain gardens can help mitigate these problems by restoring habitat and mimicking natural patterns of water movement. They are key elements of sustainable landscaping and have many environmental benefits:

  • They capture and conserve precious rainwater and snowmelt rather than diverting it to storm drains.
  • They help recharge depleted stores of groundwater by allowing more water to soak into the earth.
  • They help to minimize erosion and flooding
  • They reduce water pollution, since they give plants and soil microorganisms the time to break down water-borne toxins
  • They minimize the need for supplemental garden irrigation

While fulfilling all these utilitarian purposes, rain gardens can also be beautiful additions to home and commercial landscapes. Local native plants are best suited

The simplest rain garden is a well-drained depression with amended soil or gravel at the bottom. More complex rain garden designs can include rain barrels or cisterns to capture runoff from roofs; bioswales or “dry creek beds”; pervious paving (which is porous and allows pass-through of water), and infiltration galleries (perforated below-grade conduits for water transfer).

Rain gardens all have two elements in common: (1) the water enters at a grade higher than where it settles, and (2) there is an overflow outlet. From there, the possibilities are endless. Rain garden designs and plantings can be modern, classical, or rustic. They can either be concealed or they can be featured elements of a landscape design.

Rain gardens should be placed at least 10 feet away from homes. They should be located in an area with good drainage, and kept away from septic systems, underground utilities, and the roots of large or established trees.

The entry sign at the Elk Grove Rain Garden Plaza (Photo © Kathy Ikeda)

For a wonderful outing and a comprehensive overview of how a well-designed rain garden functions, visit the Elk Grove Rain Garden Plazaat 9385 Laguna Springs Drive. It features an interactive sculptural fountain surrounded by different types of permeable paving; a raised composite wood boardwalk over a sunken wetland area; a garden planted with locally-sourced, low-water-use California natives and Mediterranean plant species; a shade structure fitted with rain chains and rain barrels; a large paver patio with bench seating; a dry well for groundwater recharge; and many artistic elements, including a low wall inset with colorful, student-designed ceramic tiles. A fact sheet and plant list for this garden are available online.

One part of the City of Elk Grove’s Rain Garden Plaza, with the shade structure and fountain in the background and a small portion of the landscaped bioswale area in the foreground. (Photo © Kathy Ikeda)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Until you have an opportunity to visit this rain garden, enjoy exploring these articles and resources:

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

 

 

 

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Frost Protection for Sensitive Plants

We are fortunate to live in a mild climate that allows us to grow certain fruits and vegetables during the winter. However, one of the biggest worries a gardener may have is the threat of freezing weather and frosts that can harm or kill plants and damage crops. When the local weatherman warns of “a chance of frost,” it’s important to take precautions to protect your frost sensitive plants. The timing of the first frost varies from year to year, typically it is mid-November or sometime around there. Frost injures plants by causing ice crystals to form in plant cells and on the leaf surface. This process makes water inaccessible to plant tissues and interrupts the movement of fluids.

It is helpful to know the difference between a frost advisory and a freeze warning, as well as terminology used in weather predictions. Case in point: covering plants before the sun sets can help retain heat near the plants when a frost advisory is issued. The same plant protection may have less impact following a freeze warning. NOAA’s definitions:

  • Frost: The deposition of ice crystals directly on the surface of exposed objects. In the right conditions (clear skies, winds less than 6 mph) frost can occur when observed air temperatures are several degrees above freezing.
  • Freeze: When observed air temperatures fall to 32 F or lower.
  • Killing Freeze: When observed air temperatures fall to 30 F or lower for at least two consecutive hours.
  • Frost Advisory: Issued when frost is forecast to occur at 3 or more weather observation sites.
  • Freeze Warning: Issued when a freeze is expected to occur at 3 or more observation sites.

Here are some tips that will help you be prepared and give your plants a better chance at surviving our winter weather.

Before a frost

  • Identify cold spots in landscape by monitoring with thermometers.
  • Identify plants at risk: citrus, succulents, tender perennials, tropical and subtropical plants.
  • Have supplies ready: sheets, blankets or frost cloths, lights, wraps for trunks, thermometers, stakes or framework to hold covers off foliage. Frost cloths come in different weights that can provide 4° to 8° of protection. Because the frost cloth allows some light and air to penetrate, it can stay on plants for a few days at a time. Frost cloth can lay directly on plant foliage.
  • Prepare tender plants: avoid fertilizing and pruning after August to minimize tender new growth.
  • Rake away mulch to allow soil to warm up during the day and radiate heat into the plant at night.
  • Monitor weather forecasts and note how low temperatures will be and for how long.
    Local frost: clear, dry nights, usually temperature warms during the day
    Hard freeze: temperature inversion or Arctic front, can last for days or weeks, are very damaging
  • Move potted plants to a warmer spot next to the house or under a patio cover, especially on the south side.
  • Water the soil thoroughly (except around succulents). Wet soil holds heat better than dry soil, protecting roots and warming air near the soil.
  • Cover plants before sunset to capture ground heat radiating upward at night.  Remove sheets, blankets and other covers daily if it is sunny and above freezing to allow soil to absorb heat.
  • Add heat by using outdoor lights: hang 100 watt drop lights or holiday string lights to interior of plant. Use the old C7 or C9 large bulbs, not new LED lights which do not give off heat.  Old style holiday lights that give off heat can provide up to 3° of protection.  Use lights, extension cords, and multi-outlets or power strips that are rated for outdoor use and are grounded (3-prong). Avoid connecting together more than three light strings in a line.
  • Wrap trunks of tender trees if a hard freeze is expected, using towels, blankets, rags, or pipe insulation.
  • Harvest ripe citrus fruit. Generally both green and ripe fruit are damaged below 30°, but there is some variation by species (refer to chart in UC ANR Publication 8100, Frost Protection for Citrus and Other Subtropicals).

When a frost is forecast

After a frost

Plants can be remarkably resilient. If you see signs of frost damage, do not prune off the affected parts or dig up the plant immediately. Wait until the weather warms up in late March or early April to see whether new leaves sprout. You may see healthy new growth at the base of the plant, at which point you can prune out the damaged parts. If no regrowth is noted, you may want to remove the dead specimen and replace it with a more cold-tolerant species.

For more information or if you have gardening questions, please call the Master Gardener Helpline at 209-953-6112.

 

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Insecticidal Soaps: An Eco-friendly Method of Pest Control

Most gardeners are good stewards of the land and attempt to control pests using tactics with minimal environmental impact. Insecticidal soaps have become an increasingly popular method of controlling certain insects in a very “eco-friendly” manner. Insecticidal soaps can be a valuable tool to manage insect and mite pests on houseplants, vegetables, fruits and ornamentals. Soaps control many targeted pests with fewer potential adverse effects to the user, beneficial insects and the environment compared to more traditional pesticides. To be most effective, it’s important to understand how insecticidal soaps “work,” to know their mode of action, and to recognize their benefits and limitations.

What is insecticidal soap?

Soaps are made when the fatty acid portion of either plant or animal oils are joined with a strong alkali. They are potassium salts of fatty acids. Commercial products contain a blend of selected fatty acid chain lengths.

How do insecticidal soaps work?

Insecticidal soaps kill by suffocation, they appear to disrupt the cellular membranes of the insect, and they remove protective waxes that cover the insect, resulting in dehydration. There is no residual insecticidal activity once the spray application has dried.  Insecticidal soaps rapidly degrade and wash off of leaf surfaces. Insecticidal soaps are also an effective leaf wash to remove honeydew, sooty mold and other debris from leaves.

Benefits of Insecticidal Soap

Insecticidal soaps are most effective on soft-bodied pests such as aphids, lacebugs, leafhoppers, mealybugs, thrips, sawfly larvae (pear and rose slugs), scale insects (especially scale crawlers), plant bugs, psyllids, spider mites and whiteflies.  Insecticidal soap has less effect against insect eggs. Insecticidal soap are also less effective against hard bodied pests such as beetles. Some soaps are labeled for suppression of powdery mildew on certain plants.

Soaps have low toxicity to mammals. However, they can be mildly irritating to the skin or eyes. Insecticidal soaps are biodegradable, do not persist in the environment, and they do not contain any organic solvents.  Many formulations of insecticidal soap can be used on various food crops up to the day of harvest. Some plants are sensitive to soap sprays and may be seriously injured by them. Read the label to make sure your plant is not one of them.

How to Apply

Insecticidal soaps should be applied when conditions favor slow drying to maximize effectiveness, e.g., in the early morning hours with dew coverage or in the early evening. Avoid treating with soaps on hot sunny afternoons which promote rapid drying. Thorough coverage is vital for the soap to be effective: Spray thoroughly, but not beyond the point of runoff. Repeat applications may also be needed as determined by follow up scouting.

Insecticidal soap mixed in hard water with a high mineral content may be less effective and more toxic to the treated plants. A precipitate (soup scum) may be formed when the metal ions (e.g., calcium, iron or magnesium) found in hard water bind to the fatty acids in the soap. Because insecticidal soaps are toxic to fish and aquatic organisms, do not use near bodies of water.

Making your own

You may think that homemade soap sprays can be a low-cost alternative to store-bought sprays since insecticidal soaps are chemically similar to many household liquid soaps but there is a substantially increased risk of plant injury with them. Dry dish detergent and all clothes-washing detergents are far too harsh to use on plants because of all the additives in them. Some soaps and detergents are poor insecticides. However, there are many features of commercial insecticidal soap products that distinguish them from the dish washing liquids or liquid hand soaps that are sometimes substituted. Commercial soap sprays are generally better because they are designed specifically to control insects and minimize plant damage.

In general, soaps are effective tools in an integrated approach toward pest management if they are used properly with an understanding of their limitations and benefits. Chemical control should be used only after all other integrated pest management methods have failed. As with all pesticides, however, there are limitations and hazards associated with their use. Understand these limitations, and carefully follow all label instructions.

For more information on pesticides and pesticide alternatives, visit the UC IPM website, http://ipm.ucanr.edu. 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: http://sjmastergardeners.ucanr.edu

 

Information for this article was adapted from the University of Colorado Extension and University of Connecticut Extension.

 

 

 

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Leave the leaves this fall

Autumn is here! Although the fall season officially began more than two months ago, it finally feels as if it’s arrived. The cooler temperatures are invigorating and a welcome change, and rainstorms during the last two weeks have brought much-needed precipitation and relief from smoky skies.

Fall is one of my favorite times of year. We’re fortunate to have lots of beautiful deciduous trees in our county: ginkgo, liquidambar, Chinese pistache, Japanese maple, and more. When their leaves display peak fall color, the vibrant hues are like a celebration. The party only ceases when the colors fade and the leaves flutter to the ground.

And then begins the dilemma: what to do with all those fallen leaves?

Sadly, many homeowners still deal with the bounty of autumn leaves by collecting, bagging, and disposing of them. Leaves are treated as a nuisance or as trash to be hauled away to the landfill.

Fortunately, most municipalities are changing this practice by handling “green waste” separately from household trash and by implementing composting programs. In California, these actions were in large part driven by Assembly Bill 939 (AB 939), the 1989 law mandating that all cities and counties divert at least 50% of their waste stream from landfills. Despite laws such as these, the U.S. Environmental Protection Agency estimates that yard waste (leaves and other plant material) still amounts to roughly 13 percent of our country’s municipal solid waste!

Leaves are usually removed from most residential yards and commercial properties and taken to a collection facility of some type. Instead of moving your leaves offsite, there are many ecologically sound reasons to “leave the leaves” in your landscape:

  • Your trees invest a lot of time and energy producing all those nutrient-rich leaves, most of which can be allowed to remain where they drop in garden beds. They form organic mulch that retains soil moisture, suppresses weeds, improves soil health, and supports beneficial soil organisms.
  • On lawns, leaves can be chopped up using a mower with a sharp and specialized mulching blade. The resulting tiny leaf bits can be left in place along with grass clippings; they will settle into the lawn, decompose slowly, and act as a natural soil amendment. (Whole leaves should not be left on lawns.)
  • Allowing your leaves to remain where they fall saves a lot of time, effort, and even money (particularly if you pay for yard maintenance).
  • Fallen leaves help support a diverse ecosystem. Many birds, small mammals, lizards, and beneficial insects use dead leaves for nesting material, shelter, and food.

If you can’t keep your leaves in place for some reason, you can still collect them and use them on your property in other ways.

  • Large leaves can be cut into smaller pieces using a lawnmower or shredder and then redistributed as weed-suppressing mulch in the landscape.
  • Leaves can be used as the brown matter component in a compost bin. The finished compost can later be used to “top-dress” and enrich your soil.
  • Leaves can be piled on a patch of open soil. If kept moist, they will soon break down into “leaf mold” (partially decomposed leaves) that makes a rich soil amendment

Of course, there are some special considerations. Leaves from infested or diseased trees should be collected and disposed of to prevent spread of harmful organisms. Leaves from certain types of trees (walnuts and eucalyptus species, for example) can be allelopathic, which means they can harm other plants or inhibit their growth; these leaves should not be left in place.

Yet another reason for leaving the leaves is that large-scale leaf collection and removal can be detrimental. Consider these facts:

  • Leaves stuffed into plastic bags or other non-biodegradable containers can’t be commercially composted; they must be handled as trash, not as a reusable resource.
  • When placed in a typical landfill environment, organic leaf matter doesn’t receive enough oxygen to decompose properly. Instead, it produces methane gas, which is a greenhouse gas associated with climate change.
  • Most commercial-grade leaf blowers have polluting two-stroke gas engines, although cleaner four-stroke engines are being phased in. Research shows that a typical leaf blower operated for half an hour generates as many pollutants as a car driven for 50 to 400 miles! They are also noisy and sources of particulate pollution from blowing dust. (If a leaf blower or mower must be used, consider a quiet and non-polluting electric or battery-powered model.)
  • Vehicles used by municipal leaf removal services and commercial landscapers generate lots of air and noise pollution while collecting, transporting, and moving leaves.

Personally, when I need to collect or move my leaves, I still love my rake. It’s cheap, non-polluting, and quiet to operate, and using it is good exercise and an opportunity for some fresh air and peaceful time outdoors. It’s also a joy to get an up-close look at fall leaves with their different forms, ornate vein patterns, and hues of yellow, orange, and red.

This autumn, consider a different approach to your leaves. Leave them where they fall when possible, and when not, keep them on your property and treat them as the valuable resource they are.

If you’d like to try making compost, see these resources:

 

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Camellias are wonderful shrub/trees for winter blooms

A 'Debutante' blossom has a wonderful elegans form. (All photos by Lee Miller)After downsizing to a smaller place last year there is one thing that I miss—the dozen Camellias that I planted over the years as well as two really old ones at my Victorian homestead. I think these two older Camellias were close to 100 years old which tells you that, once established, these are

This 'Debutante' Camellia is 20 feet tall and likely over 100 years old.

tough plants. One is a gorgeous large, light pink, informal double-style bloom named ‘Debutante’ and it was developed initially as ‘Sara C. Hastie’ around 1900 in the Magnolia Plantation and Gardens, South Carolina. It was later renamed ‘Debutante’ for sales appeal. Fortunately, I do have one mature white-blooming Camellia at my new residence and maybe I will add more.

Camellia japonica blooms from late December through March depending on the variety. There are now a large number of hybrids of C, japonica (about 2,000 named cultivars) which originally were understory plants in the mountain forests of Asia. Camellia japonica is one of 250 species and one of these, C. sinensis, is widely planted for its tea leaves so thanks to Camellias you get to enjoy tea. Another species, Camellia sasanqua, is also planted as an ornamental and although not as popular as the C. japonica, it does bloom earlier in November and December so you can enjoy Camellias longer if you plant both kinds.

Camellias were first sold in the United States in 1807 as greenhouse plants, but were soon planted outdoors in the Southern States. The state flower of Alabama is C. japonica. They first arrived in Sacramento, California from Japan on February 7, 1852 and have thrived there so well that Sacramento is known as the Camellia City. Each spring, the Sacramento Camellia Society, established in 1924, holds its annual flower show. Next year’s show will be held March 2 and 3 at the Elks Lodge – 6446 Riverside Blvd. Sacramento, CA  95831. It will be the 95th annual show and is the oldest Camellia show in the U.S. For more information about the society, see: https://www.camelliasocietyofsacramento.org/home.html.

Magnolia Plantation and Garden in Charleston, South Carolina has 20,000 Camellias in its garden collection from the 19th century to the present. One of the oldest gardens in the U.S., it was first planted 325 years ago and has been open to the public since the 1870s. It has been designated an International Camellia Garden of Excellence and is visited by tourists from around the world.

A prolific red bloomer 'Dorothy Wood'.

Camellia blossoms are highly varied in form and range between 1.5 and 5 inches in size. The recognized forms are single, semi-double, irregular semi-double, formal double, informal double (previously called peony form) and elegans (previously known as anemone form).  Colors are white, pink, red, various blends of white and pink and red and white for both species and hybrids. For views of form and colors, see: https://en.wikipedia.org/wiki/Camellia_japonica.

Both Camellias are not difficult to grow, but it is important to do some things correctly to avoid failure. Plant it right and in the right place. The roots are shallow and have high oxygen demand. They do

 

This 'Adolphe Audusson var' has a large red and white blossom.

well in a loose, well-amended soil with good drainage and a pH of around 6.5.  Therefore it is important to keep the soil level in the pot even with that of the planting soil and not bury the root ball deep or cover roots with too much soil. It is also important that they don’t compete with other plants roots. In the Central Valley, it is best to plant them in dappled shade and give them afternoon shade if at all possible. Camellias are apparently a deer proof

 

 

‘Demitasse’ a small, beautiful camellia.

 

plant and they can handle cold weather to a point. They are limited to USDA climate zones 7-10 and can handle short bouts with below freezing temperatures, but should be protected from winds, if possible.

Camellias can be pruned to control height and spread, but it is best to plant them with lots of room. Some will grow to 20 feet tall or more and be perhaps half as wide as tall. It is good to check on the variety to see what size is listed and space accordingly. The listed height of ‘Debutante’ ranges from 6’ to 15’ in catalogues, but my ‘Debutante’ was over 20 feet high.

Camellia petal blight, a fungus, will turn blossoms brown and is difficult to control using the preferred method of sanitation. Infected blooms should be removed and destroyed from both the plant and off the ground. Mulch should be replaced annually.

The next few months are ideal to select and plant Camellias for they will be blooming in the nurseries and you can find the blooms and plants that you like. Happy Camelia 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: http://sjmastergardeners.ucanr.edu/CONTACT_US/

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  • Blog Authors

    Lee Miller

    Lee Miller is a University of Delaware graduate and retired fisheries biologist, he gardens on 10 acres and makes wine each year with the help of a cadre of friends. However, his first love is gardening and he grows various fruit trees, heirloom ... Read Full

    Marcy Sousa

    Marcy Sousa is the San Joaquin County UC Master Gardener Program Coordinator. She is a Stockton native and enjoys teaching others about gardening. She has her bachelors from Stanislaus State in Permaculture. She has been with the program since 2007. Read Full

    Nadia Zane

    Nadia Zane is a UC Master Gardener, a landscape designer and Stockton native. She has a fondness for California native plants and sustainable landscaping, which she utilizes in her work for Native Beauty Garden Design. She is a member of the CA ... Read Full
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