Garden Q&A: Do evergreens shed and what is the white stuff on my hydrangea?
By Ellen Nibali
Nov 05, 2020 at 7:00 AM
My arborvitae are turning yellow at an alarming rate. I have a long row of these and need them for privacy. Help!
Being ‘evergreen’ doesn’t mean a tree or shrub never drops old foliage. Every year, both needled and broad-leaved evergreens drop old foliage either in the fall or spring. This normal shedding occurs on the interior branches, closest to the trunk. (Dead branch tips are an entirely different matter!)
Shed foliage is about two- to three-years old, so if the tree had a great growing year two to three years ago and put out a great deal of new growth, when that year’s foliage is due to drop, it will be a lot — and look pretty alarming. Shed needles, particularly of pine, create a free, effective mulch under trees which keeps down weeds, conserves moisture and decomposes to feed the tree. It’s attractive, too. Search ‘normal leaf shed’ on the Home and Garden Information Center website.
There is something white, hard and prolific all over my climbing hydrangea. They’re even all over the brick where the hydrangea is climbing. It can’t be good.
Cottony camellia scale is a soft scale, a sucking insect that commonly pops up on holly, magnolia, camellia and euonymus. Honeydew (a sticky clear liquid excreted by the scales) and sooty mold (a black fungus that grows on the honeydew) are the major problems caused by this insect. In June, females die and may fall off, leaving only the white ovisacs (containing eggs). Immatures hatch through June and remain on the underside of leaves or bark through the winter. At this point in the year, we recommend you spray with a dormant oil after leaf drop. Follow label directions.
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.