Maryland Grows

Q&A:  Why didn’t Japanese maples lose their leaves last fall?

Japanese maple with brown leaves

This Japanese maple retained dried leaves during the winter. Photo: D. Ricigliano

Q:  Most of my Japanese maples are still full of dead leaves. They never exfoliated in the fall to leave bare branches. Will this affect new growth in the spring? Should I just let them be?

A: We have received several questions about Japanese maples that are still holding on to brown leaves that didn’t drop last fall. Some crapemyrtles also have held their leaves during the winter. This issue has been reported in several areas of Maryland, which suggests it is due to an environmental factor. An unusually warm autumn followed by a quick cold snap likely interfered with the trees’ normal winter preparation processes.

As the days shorten in the fall, trees go through a series of biochemical and physical changes to prepare for winter survival. In deciduous trees, this includes the development of an abscission zone of cells where the branches connect to the base of leaf stems (petioles). A layer of cells essentially seals off the branches to protect them from water loss, and then the leaves are shed from the tree. We suspect the fall cold snap interrupted this process and normal leaf abscission did not occur in some trees.

Some types of trees naturally do tend to retain dead leaves during the winter. American beeches and many oaks exhibit this trait, called leaf marcescence. This occurs most often on juvenile trees. It may be a strategy to protect buds from winter damage or to discourage deer browsing. Trees may also wait until spring to shed their leaves, thus providing a fresh source of nutrient-rich organic matter to the root zone where soils are otherwise poor. The exact reasons for leaf marcesence haven’t been determined completely.

There is nothing you need to do for your Japanese maple at this time. If your tree was otherwise healthy, new growth will emerge in the spring and the old brown leaves will drop off eventually.

Sources and Additional Resources

By Christa Carignan, Coordinator, Digital Horticulture Education, Home & Garden Information Center

Have a plant or pest question? University of Maryland Extension’s experts have answers! Send your questions and photos to Ask an Expert.

Featured Video: Mushrooms and Trees’ Symbiotic Relationship

David Clement, Ph.D. Extension Specialist, Plant Pathology, explains how fungi grow and feed on tree roots under the ground and sprout above ground as mushrooms.

Visit the Home & Garden Information Center website to learn more about Wood Rots and Decay of Trees and Shrubs.

Microgreens: Tasty Accents from Small Spaces

My first response to microgreens was: “Why would I spend my time growing 3-inch tall plants to eat?”

Then I thought about all of the tiny leafy green plants (beet, lettuce, kale, basil, etc.) I had eaten over the years in the process of growing transplants at home and in greenhouses. And it started to make more sense: why not plant seeds closely in a container to just grow baby plants?

"Brassica" microgreens

Tray of “brassica” microgreens ready to harvest

Benefits: When you eat microgreens you are ingesting the cotyledons, stems, and small expanded true leaves of edible plants. Some reasons to give them a try:

  • High in anti-oxidants and other health-promoting substances, like vitamin C, vitamin E, beta-carotene, and lutein
  • Can be grown year-round inside with strong natural light or inexpensive fluorescent tubes
  • Great for kids at home and in school- sow seeds, watch them sprout and grow for 10-14 days, and eat!
  • Wonderful assortment of colors, flavors, and textures

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Plant Selection: The Big Picture

Before deciding what plants to buy, determine what you want your overall landscape to do for you. Are you an avid gardener, have an active family, or want a landscape that doesn’t require a lot of maintenance? The answer indicates how you will use or interact in your landscape and that helps guide your plant options.  

Included here are some functions that plants can perform in the landscape and the outdoor spaces where you would use them.

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Vegetable garden planning: what doesn’t start from seeds

As you’re planning your vegetable garden for this year, you’re probably thinking seeds, seeds, seeds. But not everything in the garden needs to begin with seeds. In some cases, plants started by someone else are a convenient or even economical choice. And some crops, like potatoes, are grown from last season’s tubers rather than from seeds.

IMG_3617

Leek seedlings planted at the Derwood Demo Garden in spring 2017

Here are some crops you might consider giving a little head start by purchasing plants, tubers, bulbs, etc. Most of these will also be available in local garden centers in the proper season, but if you order them from seed companies now, you will have a much wider choice of varieties, and they will ship at the right time for planting.

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Lawn and Garden Tips for February

Grass seed. Photo: John W. Jett, Horticulture Specialist WVU Extension Service

Lawn

  • Late February through the end of March is the second-best time (the optimum time is late August through mid-October) to overseed your lawn to make it thicker or to cover bare areas. The freezing and thawing of the soil this time of the year actually helps the seed to get good soil contact. (PDF) HG 102 Lawn Establishment, Renovation, and Overseeding.
  • Be careful to keep ice-melting products off turf to avoid killing your lawn.
  • Do not use fertilizer to melt snow. See PDF Melting Ice Safely

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Q&A: What Is Causing Trees to Lose Their Bark?

tree with woodpecker damageSeveral observations of tree bark damage like this have been reported to the University of Maryland Extension’s Home & Garden Information Center (HGIC) recently. 

Q: I was walking in the woods near my house and noticed bark trimmed off a tree. It looked like a buck rubbing with their antlers, but it was up high, about 10 feet. A couple weeks later, I was in my back yard and noticed the same thing on one of my trees. Can someone please help me figure out what is going on? Thanks!

A: This looks like damage from woodpecker feeding. Judging from the bark pattern of the tree, this looks like an ash tree. Many ashes in Maryland are becoming infested with the invasive emerald ash borer (EAB). Taking a close look at the photo, it appears there are borer holes in the trunk where the bark was removed. The EAB larvae that feed on the nutrient transporting layers under the bark are a good food source for birds such as woodpeckers. This woodpecker impact is being seen and reported more and more frequently.

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