Experts tackle readers’ garden questions.
Q: My neighbor gave me this plant when they moved. It’s beautiful when it’s healthy. What is it? What’s eating it? What can I do about it? I’ve put broken egg shells around it to keep snails away. I sprayed it with soapy water to kill any insects. That just caused brown spots.
Barbara Chance, Elverta
Master gardener Dennis Appleby: The plant is a Ligularia dentata. This perennial is grown primarily for big leaves (more than a foot across). In midsummer to early fall, it produces 3- to 5-foot stems topped with large heads of orange-yellow daisies.
They are grown in zones 8, 9, 10 in sun, part shade or full shade. It likes well-drained, moist to dry soil with medium watering.
The plant is also a favorite of snails and slugs. The picture you enclosed shows damage that could have been caused by wind, snails, slugs or a combination of all three. You said that you used egg shells to keep the snails away. UC Davis has not done research on this method so we do not have any information.
A good system of controlling snails and slugs requires a combination of methods. One of the most effective methods to control snails and slugs is handpicking. This is best done in the late afternoon or evening.
It is also helpful to eliminate all places where they can hide during the day. Boards, stones, debris, weedy areas under tree trunks, and dense ground covers such as ivy are ideal sheltering spots. At first you may have to handpick daily, but with diligence, you may be able to limit to once a week.
Two products for controlling snails and slugs that you may want to consider is copper foil, specifically sold as a snail barrier, and snail bait. These are more effective when used with previously mentioned deterrents.
For the latest information on snail and slug treatment, go to ipm.ucdavis.edu/PMG/PESTNOTES/pn7427.
The use of soapy water is not recommended to deter snails. Also keep in mind that not all soap can be used in the garden to control pests. The soap must be labeled for use as an insecticide; regular kitchen soap will not work.
There are a number of plants that are sensitive to insecticidal soaps, one of which is any plant with waxy leaves, such as Ligularia. Always test a small area of your plant before spraying the entire plant.
Editor’s note: A member of the aster family, this plant is also known as summer ragwort or leopard plant.
Dennis Appleby is a UC Cooperative Extension master gardener for Sacramento County.
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