x
 
 
Learn which plants thrive in your Hardiness Zone with our new interactive map!

Elm Trees

Elm trees can become too invasive.

How to Kill Elm Trees

Elms (Ulmus) as large shade trees that produce dense foliage and can grow as high as 100 feet. This lovely tree, which normally increases property values, can become too invasive. Over time the roots can extend too close to structures, threatening to cause cracks in the foundations. When this happens the Elm tree can be very tricky to kill if proper procedures are not followed.

Slide a sharp knife underneath the bark. This will loosen the bark of the tree from its green layer. These cuts into the bark are referred to as "frills."

Pour some tree poison into the spray bottle at full strength.

Spray the tree poison into the patches of loosened bark. The tree's phloem will take the poison directly to the roots, killing off the tree.

How to Kill the Elm Leaf Beetle

Look at the leaves of the elm tree and verify the presence of black worms, which are the larva of the elm leaf beetle. Killing the population of beetles should occur only after the larvae develop, not while they are still in the egg stage.

Fill a hand-held or backpack garden sprayer with an insecticide containing the ingredient carbaryl. Add enough water to dilute the insecticide mixture to 2 percent solution. Close the sprayer and shake to mix thoroughly.

Direct the nozzle of the sprayer at the lowest limb of the tree where it meets the trunk. Spray a 2- to 3-foot band of insecticide around the trunk. Spray all other trees in the area using the same method to prevent the beetles from migrating to them.

Empty the garden sprayer and rinse it out, or use a second clean sprayer. Fill it with an insecticide solution containing azadirachtin and spray the branches and foliage of the tree until they are saturated. This targets the adult beetle population.

Repeat the application of the insecticide band on all of the trees each spring for at least two to three years to ensure control of elm leaf beetles.

How to Identify Dead Elm Trees

Evaluate the tree for signs of illness and dying. Signs to watch for include little or no leaves in summertime or discolored leaves in spring and summer. Lack of leaves is a sign that the elm tree is not drawing nutrients from its roots and transporting them to its branches.

Check for mushrooms. Morel mushrooms grow around the base of dying and dead elm trees because they feed on the bark that the tree is shedding.

Diagnose any possible diseases. If the tree has discolored bark, no wintergreen odor in the winter and no leaves in the summer, it has contracted Dutch elm disease, the most common killer of elm trees.

Cut into a limb with a sharp knife. If the wood underneath the bark is brown or black, then the tree's internal tissues have died off.

How to Plant Elm Tree Seeds

People used to use elms to line streets because they grow well even in urban areas.

Prepare a mixture of clay, charcoal, peat, potting soil and pebbles. Elm trees grow best in soil that drains well. Soil pH can range anywhere from 5.5 to 8.

Fill a medium-sized pot three-quarters of the way up with the soil mixture.

Insert the elm seed into the potting soil, wing side up. Cover the seed with soil only to the point where the seed meets the wing. There is no need to plant the seed deeper, as elm seeds rarely are able to penetrate completely into the soil and will propagate in nature without full immersion.

Water the seed and place it in full sun. Keep the soil moist--but not saturated--until the seed germinates. This should take one to two weeks but can take up to two months, according to the U.S. Department of Agriculture Forest Service.

How Do I Identify Elm Trees in Spring?

How Do I Identify Elm Trees in Spring?

Examine the overall shape of the tree branches, even if there is no foliage present. There should only be four to five main vertical branches growing from the trunk, although there can be many more shorter horizontal branches. In addition, the overall shape of the branches should resemble an umbrella.

Move close to the tree trunk and look at the color of the bark. It should be dark gray with streaks of brown. Some older elm trees can have a white silver gray coloring instead of being dark. You should also see many raised, vertical ridges in the bark.

Pick off one set of leaves from the tree, even if they are still small. If it is an elm tree, there will be three oval-shaped leaves attached to a single stem. The edges of each leaf have a serrated appearance and you can clearly see the veins along the flat surface of the leaf. The leaves can be between 4 and 6 inches long.

Examine the ground underneath the tree for large chunks of bark that have fallen off. This is a sign of an elm tree that has started to die usually from disease or cold damage the previous winter.

How to Harvest Slippery Elm

Use a sharp knife to slice away the bark from the main trunk of the tree. Cut deep enough into the tree so that you see the green layer that is somewhat slimy to the touch. Then begin peeling away the bark, down the tree's trunk.

Use scissors to cut up the strips of bark into small, square pieces.

Place the cut pieces of bark onto an old window screen or a piece of wire mesh for approximately two weeks in a cool, dry location. Allow it to dry until it is hard and brittle to the touch.

Place the pieces of dried bark into labeled, airtight storage containers and store in a cool, dark place.

How to Top & Prune Elm Trees

Cut out all dead, broken and diseased branches. Make all cuts about 1 inch from the branch collar (the point at which the branch grows out of the trunk or out of a larger branch).

Cut all branches that are growing sideways through the canopy or at a downward angle.

Cut all branches that are rubbing against one another because the rubbing can break the bark and allow the elm bark beetle an easy entry point.

Top the tree, if necessary, by cutting vertical branches 1 inch from the branch collar. The pain trunk can be topped as long as you do not cut more than a third of the tree's height.

Paint all cuts immediately with a tree wound compound or latex paint. This will help prevent elm bark beetle from gaining access to the tree.