We put in a witch hazel in 2012 for the February floral burst. It never drops its leaves so the blossoms are hidden. Short of continuing to snip off every leaf in January before bud break how can I encourage complete abscission layer formation and leaf drop in the fall? Gretchen
Answer
Thank you for a great question. You are observing a shrub with "marcescent"" leaves. The term "marcescence" comes from a Latin word meaning "to shrivel"; it refers to dead leaves that remain attached to shrubs or trees all winter long. Normally, as a tree or shrub prepares for winter, the leaves will pass their nutrients back into the stem of the tree or shrub for storage. Then two layers of cells are formed between the base of each leaf and the tree or shrub in what is called the abscission (or separation) zone. One layer of cells breaks easily because it is very thin and brittle and the other layer on the tree or shrub side is protective and "corky". As the corky layer expands, the bond that holds the leaf is broken and the leaf falls. Weather and genetics can each play a part in why some trees and shrubs don't fully develop an abscission zone and the dead leaves stay put. Some years, the winter frost arrives too soon and kills the leaves before the abscission process is completed and the leaves stay on through the winter. Eventually, when spring arrives, the old, dead leaves get pushed off by the new growth. Some trees and shrubs are more prone to marcescence than others. It is common to see oak and beech trees hanging onto some or all of their leaves throughout the winter. Some varieties of yellow-flowered witch-hazels tend to hang on to their old, dead leaves all winter long, which, as you point out, makes it difficult to see the flowers that bloom between January and March, depending on the variety of the witch-hazel. Short of continuing to do
what you have been doing, i.e., cutting off the dead leaves by hand, there is not much else you can do. The good news is that as the plant matures, this characteristic may disappear completely and marcescence will no longer be an issue. Good luck.
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About Linda Lillie
Linda K. Lillie is the President of Sprigs & Twigs, Inc, the premier
landscape design and maintenance, tree care, lawn care, stonework, and carpentry
service provider in southeastern Connecticut since 1997. She is a graduate of
Connecticut College in Botany, a Connecticut Master Gardener and a national
award winning landscape designer for her landscape design and landscape installation work.