Lawn and Garden Tips for March

Seeds

Ornamental Plants

  • Starting Seeds Indoors – Many types of annual flower plants can be started indoors this month. Generally, most are started 5-6 weeks before they are planted outdoors.
  • Spring bulbs are emerging and some are even flowering at this time. Exposed leaves may be burned later by very cold temperatures but the spring flower display will not be adversely affected.
  • Groundcovers are arriving in local nursery and garden centers this month. They are a great alternative to grass where grass won’t grow, where you have heavy shade or tree root problems and on steep slopes.

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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 Extension.

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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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. Lawn 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 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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How climate change works

In my last post, I addressed some common questions that farmers ask about climate change. Although I considered why the scientific information documenting climate change is trustworthy, I didn’t actually explain how climate change works. A savvy reader picked up on this and was dissatisfied that I didn’t present the relationship between increasing CO2 and global warming. In this post, I’ll correct that omission.

The CO2-temperature connection occurs through the “Greenhouse Effect”, a process that almost everyone has heard about but surprisingly few people can explain.

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