Garden Q&A: Don’t worry about leafcutter bees or trees damage from unusual spring weather
By Ellen Nibali
Jun 25, 2020 at 7:00 AM
What is munching on these leaves? I don’t see any caterpillars, even under the leaves.
Good question to wrap up National Pollinator Week. These are harmless borrowings of the leafcutter bee, an important native pollinator.
The female snips off these semicircles of leaf to roll into a nest for each of her eggs. Completed, it looks rather like a short cigar, except it’s green. Sometimes she throws flower petals into the mix, making a very striking “cigar.” Since she hides her nests in holes she finds, you’ll rarely encounter them.
You might not see adults bees either, which resemble small, fuzzy, yellow and black bumblebees. They like the company of one another, but, being rather shy, they may wait for you to leave before resuming activities, such as gathering pollen for their offspring to eat when they hatch. Their rare defensive or accidental sting is so mild, it is usually more like a mosquito bite.
Leafcutter bees pollinate many plants, notably vegetables and fruits.
Every Japanese maple in my neighborhood has diseases this year. Some have white spots. Some have browning leaves. Many have both. Infected leaves seem to start on top of the trees. Is this one or two new diseases?
Japanese maples were hammered by unusual weather this spring, namely repeated late frosts occurring after early warmth lured them into leaf. They were not alone.
A huge range of plant species suffered cold damage, including surprising ones such as fir. Hydrangeas were hit hard. Most plants can sustain some leaf loss, and this cold injury will prove to be just a temporary setback. They should continue to put out new flushes of growth and largely cover damaged leaves.
University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Maryland’s Gardening Experts” to send questions and photos.