In Bloom

<< Back to Articles

Ask Burton: Q: My Japanese maple’s leaves have suddenly shown numerous small holes, and there are tiny cones (1/4″) made of dried leaves sticking to the top of many leaves. What is happening?

Posted on May, 10

A: We’ve had customers showing up to the nursery earlier than in any year we can remember with bagworms! May 4th marks our first sighting this year, when we’re accustomed to looking for bagworms starting the week before Memorial Day.

Bagworms are most frequently pests to junipers, cedars, and cypress, but they’ll also feed on roses, Japanese maples, and Indian hawthorn. Spray susceptible plants with one of two organic insecticides, Bacillus Thuringensis (B.T.), or spinosad, which we sell under the Captain Jack label. Both are low-toxicity pesticides which are safer around people and pets, and very effective for this problem.

If you had bagworms the year before, and particularly if you had a bad infestation, spray before you see the problem because it’s likely to show up one more time. Each of the bags you miss hanging dry on the plant from a previous year can produce anywhere from 500 to 1000 young the next year, and are best controlled by hitting them as soon as they emerge.

Burton specializes in diagnosing and solving plant problems. If you have a question for Burton, please email him at and include photos showing the problem.