Plant it right and don’t plant invasives.

PlantRight is an organization that works to reduce the number of invasive plants sold at nurseries in California. Master Gardeners and other volunteers have helped conduct eight annual surveys to assess how many invasive plants are currently for sale and to encourage nurseries to stop selling such plants. This year, PlantRight is not doing a nursery survey, but instead is concentrating efforts on outreach to landscape professionals (e.g. architects, designers and contractors), and to water districts promoting sustainable landscaping. In the 2017 survey, the rate of nurseries selling invasive plants continued to decline; dropping from 44 percent in 2014 to 29 percent in 2017. For a list of invasives see: https://www.epicgardening.com/invasive-plant-species-in-california/

I have battled many invasive, obnoxious plants in my lifetime, so I am always glad to warn others about the hardships that such plants can bring your way. I can say that I have not won a battle with invasive plants. When I bought my farm 42 years ago I inherited some nasty plants along with the beautiful redbuds that caused me to name the place Redbud Farm.

Periwinkle (Vinca major) was growing in several places and it still is today though greatly reduced in abundance. I tried hard to eradicate it, but it has proven very resilient. The roots must be removed or it comes back and I suspect residual seeds too. It has become a major invasive plant in the shade of redwood trees on the north coast where it displaces native understory plants.

Another invasive is Algerian Ivy (Hedera algeriensis) along with others of its ilk who provide good rat habitat. Although I removed it long ago, I keep finding new plants coming up and I am uncertain if this is due to birds dropping seeds or residual seeds from the original plant. It is mostly now a nuisance weed. Birds dropping seeds reminds me of Privet (Ligustrum sp.) whose seeds cause lots of weed trees requiring vigilant weeding, even if you don’t have one in your garden.

Italian Arum (Arum italica) is a woodland shade-loving plant that grows from corms. It resembles a jack-in-the-pulpit with large, arrow-shaped leaves. It grows in the winter and fades away with summer weather but leaves a large seed stalk with orange seeds. It reproduces with seeds along with deeply rooted corms that divide. It naturalizes readily and did so long before I bought the farm, so basically I was stuck with it.

In small locations you can cover the plant with a board and starve the corms for a year or more. This approach is not going to work when it is abundant everywhere. Herbicides do not work and digging out the corms is only practical in small areas. It is difficult to remove all the small corms.

I did remove Arum seed stalks before the seeds were scattered which perhaps helped curb their spreading. Years ago, to develop my step-daughter’s work habits, I paid her 2 cents for every seed stalk pulled and she pulled a few hundred. However, since all parts of the plant are poisonous it is wise to be careful when being in contact with this plant. Would you believe that on-line nurseries will sell you, for only $25 for 5 corms, a bundle of misery and trouble?

Small-leaf spiderwort (Tradescantia fluminensis) is a shade-loving creeping perennial herb that roots at nodes, I thought I had gotten rid of this plant, but it re-emerged to take over all shady understory areas. It smothers everything with vigorous growth and the rooted sections break off easily so removal is difficult. Herbicide such as a 3 percent glyphosate is recommended, but this may not be a solution in circumstances where other plants are present.

Spiderwort is a problem in Florida and in New Zealand where it covers vast areas of understory forests. Recently, I belatedly saw some being sold at a plant sale that I was involved with. I hope none were purchased and next year I will insist we not offer it for sale.

Bermuda buttercup or Buttercup oxalis (Oxalis pes-caprae) is an invasive impossible to eradicate as it grows from bulbs and it makes a bunch of new little bulblets every year. The flower is pretty and blooms in late winter/spring. I had to acquiesce to living with it.

Bermuda buttercup or Buttercup oxalis (Oxalis pes-caprae) is an invasive impossible to eradicate as it grows from bulbs and it makes a bunch of new little bulblets every year. The flower is pretty and blooms in late winter/spring. I had to acquiesce to living with it.

Last week was Invasive Species Action Week in California to awaken the public to the downside of invasive species. I wrote this article before I knew that. For more information see: https://www.wildlife.ca.gov/conservation/invasives/action-week . Sometimes, the only way to get rid of invasive plants is to sell the farm; so I did. To all gardeners, I wish you happier gardening sans invasive plants, so plant carefully.

If you have a gardening related question, you can contact the UC Master Gardeners at 209-953-6112. More information can be found at: http://sjmastergardeners.ucanr.edu/

 

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