Q. I always wanted to have a formal box-shaped privet hedge. But my hedge is open at the bottom and the woody stems look straggly. What should I do?
-- K. L. of O'Fallon
A. The most common mistake in maintaining a hedge is improper pruning. The base of the plant should be the widest and the top should be the narrowest part. If the top is wider, it shades the lower part of the plant, causing lower branches to lose their leaves. This makes the whole hedge very unattractive. For an older, established hedge you should prune it back almost to the older woody stems each time you prune. This information also applies to yew plants.
Q. I have a Chinese elm in my yard and I have noticed a whitish liquid coming out from under the bark about 8 feet up from the ground. What is this, and what causes it, and will it kill the tree?
-- F. H. of Collinsville
A. Chinese elms (Ulmus parvifolia) and (Ulmus pumila) are two distinct species. The first listed here is a tough and durable tree. I'm afraid you have the second one, which is sold also as a Chinese elm. It's leaky condition is termed "slime flux."
Most nurserymen refer to the first one (Ulmus parvifolia) as the lacebark elm, and don't call it a Chinese elm anymore. The lacebark elm has a tannish bark with a bright orange irregular "river" lines running over the tan bark.
The Ulmus pumila has weak wood and is easily damaged in storms. Wherever an injury occurs, there usually is a separation of the bark from the wood. Water enters this separation very easily and runs downward. Eventually, this liquid oozes from cracks on the trunk during the growing season.
You will notice that this liquid is rather sour smelling because it contains the bacterium (Erwinia nimipressuralis). The species name of this bacteria refers to the pressure that builds up under the bark from fermented sap, which eventually finds a weakness in the bark and breaks through to the outside of the tree. Large areas of the bark will become coated as it flows down the outside of the tree and gives off this horrible odor. But when it dries to a grayish-white on the bark, most people refer to the common name of slime flux.
The wound never heals. The tree can live many years in this horrible condition. You can drill a hole upward under the bark into the wound, then place a 1/2-inch plastic tube upward into the hole to drain the liquid down to the soil level without it touching the bark to prolong the life of the tree. But the tree will die eventually.
You will notice over time that branches will dry up and fall off the tree from time to time. The tree is often under water stress, which will cause wilting and scorched leaves. These branches fall very easily to the ground, especially in windstorms. If you notice large sheets of the bark falling off, this indicates the tree has become a hazard and should be removed.
Do it now
WOODY PLANTS: Complete pruning before buds begin to swell.
CRABGRASS: When Forsythia (Golden bells) shrubs begin to bloom, apply pre-emergent herbicide to the lawn to control crabgrass and keep other lawn weeds from germinating.
FRUIT TREES: Apply a pre-bloom multipurpose fruit spray.
COOL SEASON CROPS: Plant directly into the garden as soon as the soil dries out enough to be worked -- peas, lettuce, spinach, carrots, beets, turnips and parsnips.
Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Editor Pat Kuhl, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427.