Fungus could kill big oak tree

Backyard Q&A

In the Garden

December 07, 2003|By Dennis Bishop | Dennis Bishop,Special to the Sun

A large oak tree in my back yard has several dead branches and some branches had unusually small leaves this summer. Also, there were mushrooms growing at the base of the tree. Are they related, and what is the problem?

Yes, they probably are related and it may indicate a very serious problem. The dead branches and small leaves are symptoms of disease infecting your tree, while the mushrooms are part of the fungus that is causing the disease. The fungus invades weakened trees through wounds in the bark or roots and then moves into tree trunks and branches. As it invades the tree, it kills and feeds on interior tissues causing them to rot. As the fungus matures, it produces mushrooms at the base of the tree or on the trunks and branches.

Mushrooms at the base of the tree generally have a distinct stem and are club shaped, however the mushrooms that grow on tree trunks and branches are typically broad, flat, and without a distinct stem. The latter are called shelf mushrooms or conks. Trees that have mushrooms growing on them may live for many years, but the disease may compromise the integrity of the tree and make it prone to falling. I would call a certified arborist and have the tree inspected as soon as possible.

We recently purchased a rowhome in Baltimore with a small sloping front yard that is covered with ivy. We would like to remove the ivy. What do you suggest?

Ivy is a woody evergreen vine that is very tenacious and difficult to remove. Here are two non-chemical options. First, you could dig it out repeatedly until all of it is removed. This is very hard labor that will be even more difficult if there are tree roots in the area. The second method would be to cut back the ivy to the ground, dispose of the cuttings, and then cover it with a layer of cardboard topped by 3-4 inches of mulch. The combination of cardboard and mulch will eventually (one to two years) smother the ivy.

If you don't mind chemicals, I would try the following: First, cut the ivy back to several inches from the ground in early to mid-spring. Second, when the ivy produces a flush of young tender leaves, spray it with a systemic herbicide like Round-up. One spraying will probably not be enough, so be prepared to spray it again in two to four weeks.

Whichever method you use, I would complete the job by tilling or turning over the entire area and raking out any remnants of the ivy. While you are at it, be sure to work in some additional organic matter. It will help whatever you replant in the area to grow.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site www.hgic.


1. Are you buying a living Christmas tree this year that can be replanted in your yard? Don't forget to inspect the root ball -- it should be large and firm.

2. Buy your Christmas tree in daylight when it can be examined closely. Needles should look fresh. Hit the butt end on a hard surface. If a lot of green needles drop, the tree is too dry.

3. Once leaf fall is complete, be sure to clean downspouts and gutters so they can freely drain melting snow.

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