More recent horticulture questions and answers

Horticulture

Radishes woody and inedible

I am a first-time gardener. Why are most of my radishes woody and inedible?

Radishes will get tough and bitter during hot weather. Mulching and drip irrigation will help keep the soil cooler.

Lewis W. Jett
Department of Horticulture

Oak tree oozing

My oak tree is about 15-feet tall. It began oozing sap from where a branch had been cut off. The sap is not thick or sticky, but is foamy at the cut. I applied tar sealant, but it oozed through. What should I do? Will I loose the tree?

Your tree has a bacterial infection that is causing the sap to ooze out. There is not much that can be done to stop the oozing, but fortunately, the consequences are not usually serious. The infection should clear itself up eventually. It is not likely to kill your tree. You might consider watering and fertilizing the tree if you have not done so to increase vigor.

Chris Starbuck
State Extension Specialist
Woody Ornamentals

Ground cover rather than mowing

I live on a well drained hill with a mix of large conifers and deciduous trees, as well as large open spaces. I have about an acre of lawn in which I want to plant perrenial seeds that will quickly grow into a ground cover invasive and thick enough to eliminate weeds. The main species would be easily maintained, low growing, winter and heat hardy (zone 5 -- Southern Missouri). I would like to plant several species, in irregular clusters, so the final result looks like a sculptured lawn, with areas of different color, texture, and height -- with the main species being the walkways. The end result would be a self-perpetuating lawn I don't have to mow or weed, and that I can walk through without damaging it or tripping myself. It has been suggested that a clover would be excellent for my needs, but I have also been told that clover grows to some 18 inches in height, which would be too tall. What ground covers would you recommend? Where can I purchase the seeds?

I can't think of any species that would fit all of your needs. Most of the materials that would be available from seed would be native grasses. White clover is fairly low growing, but tends to collapse in the heat. You might check the following source to see what they might recommend.

Missouri Wildflower Nursery
9814 Pleasant Hill Road
Jefferson City, MO 65109
573-496-3492
E-mail: mowldflrs@socket.net
www.mowildflowers.net

You might consider winter creeper, Euonymus fortunei, for some of the areas where you will not be walking much. It will grow in either sun or shade. However, it must be planted from plants, plugs or cuttings and will take a few years to become established. It is considered a no-no by many people because it is so aggressive and may invade natural areas.

Chris Starbuck
State Extension Specialist
Woody Ornamentals

Dogwood leaves die

In November we planted a white dogwood. It bloomed in April. By the middle of May it was fully leafed out. At that time my neighbor had her yard sprayed with broadleaf weed killer. I feel the tree received some mist from the spraying. Its leaves were completely dead in three days. Is it possible to test leaves for chemicals?

In my opinion, it is unlikely that spray drift from the broadleaf herbicide application in your neighbor's yard killed your dogwood tree. Even if the trees had been sprayed directly, the symptoms would have developed over about a two week period, starting out as leaf curling on the newest leaves, followed by a gradual deterioration of the foliage. I do not believe it would be worth the expense of having your leaves tested.

I can not say with certainty what may have caused the rapid browning of the leaves, but I suspect that it may have been a watering problem. Since the tree was planted last November, it would not have had the opportunity to develop roots in the soil surrounding the original soil ball. Therefore, it would have been entirely dependent on maintenance of uniform moisture in the original root ball. It is very easy to over-water or under-water a tree in such condition. Then, when hot dry weather comes on, the tree can suffer severe stress from either drought or excess soil moisture. The problem is often aggravated if the tree is planted in an un-shaded location. This is a much more likely explanation for the complete browning of leaves on your tree over a two or three day period.

Chris Starbuck
State Extension Specialist
Woody Ornamentals

Honeysuckle tree

I have transplanted a tree that I found growing on a creek bank. A friend says it is a honeysuckle tree. He says it has flowers in the
spring. I can find no information on this tree. I would like to know if there is such a thing?

The most likely candidate for the name honeysuckle tree would be the amur honeysuckle (Lonicera maackii). It can grow to 25 feet tall, sometimes with a main trunk. More commonly it grows as a large shrub. Unfortunately, this species produces many berries that are attractive to birds. It has spread rampantly throughout the state, especially in shady areas and is considered by many to be a noxious weed.

Chris Starbuck
State Extension Specialist
Woody Ornamentals