Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

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What are some good shade trees for this area?

Shade trees are the backbone of most landscapes. They're the largest landscape plants, the ones that make the biggest visual and functional impact. Too often the decision to purchase a shade tree is based on one trait alone, such as how fast it grows. Before deciding on a tree, it's important to examine all of its characteristics, good and bad and to determine if they match your needs and the needs of your landscape.

The first consideration should be the tree's ultimate size. How tall and wide can a tree get in your landscape before it begins to cause problems. Failure to consider ultimate size is one of the most common landscape mistakes. All too often trees outgrow their space making it necessary to prune them severely to keep them away from other plants, buildings and out of overhead utility wires. This type of pruning usually destroys the trees' natural shape.

When selecting shade trees, consider the following. Does the tree have disease or insect problems which might require periodic spraying? What about clean up? Most people expect to rake leaves in the fall, but does the tree also drop messy fruits, nuts, seed capsules and/or leaf stems at other times of the year? Some trees send up vigorous shoots, called suckers, at the base of the trunk which should be removed each year. When it comes to these maintenance problems you have to ask yourself, "Do I like this tree enough to put up with its bad habits?"

You should also consider the tree's physical characteristics, ie,some trees have thorns, which can certainly be a liability especially when children are present. Some trees can seriously affect the growth of other plants. For instance, a mature Norway maple casts such a dense shade that most plants, including lawn grass, have a difficult time growing beneath the branches. Black walnut is another example. Black walnut trees produce a chemical that builds up in the soil and limits the growth of many garden and landscape plants.

Although it is tempting to plant fast-growing trees, most of them have serious shortcomings. Trees like box elder, silver maple, black cherry, Siberian elm, willows and poplars tend to be weak-wooded and can become problem trees much sooner than slower growing, stronger-wooded trees. These same trees also have the bad habit of plugging sewer and septic systems with their vigorous roots.

Once you discover the tree's potential problems it's time to look at its ornamental traits. Flower color, time of flowering, fall foliage color, fruit and bark characteristics, summer and winter texture, and branching habit are all important factors. The best landscape trees are those that have all-season interest, the ones that have something attractive and interesting to offer year-round. These are the trees that will add the most pleasure and value to your landscape.

For recommendations of shade trees for our area, visit the Missouri Botanical Garden and view its living collection for ideas. Most of the trees there are labeled. You can also find lists of recommended trees in the Center for Home Gardening and University Extension literature. Local nurseries and garden centers can also provide recommendations.