Garden Tips: Choose shade trees wisely

I am often asked to recommend a good shade tree for area yards. Before I can answer, I need to know the questioners’ expectations. Do they want a tree with bright red or orange fall color? Do they want a tree that is not prone to troublesome pest problems and one that will tolerate the summer heat? Do they want a tree that does not have invasive or shallow roots? Are they concerned about leaf litter in the fall? There is no perfect shade tree that will meet all the desired characteristics.

Size is important. If shade is important, do you want a large shade tree that grows to a height of 70 to 80 feet, such as red oak, Norway maple, and red maple? Or do you want a more medium-sized shade tree, such as linden, ginkgo or river birch that only grow to 50 to 60 feet tall? Before selecting any tree, know how tall and wide it will get and determine where you will need to plant it for casting shade where it is needed? Do you have the space?

In the “old days,” native species of trees that reached the hefty heights mentioned were the only ones available at nurseries. Now, thanks to plant breeding and selection, we can find trees that reach more manageable sizes for the typical home and lot. For example, the ‘Red Sunset’ maple, a red maple from J. Frank Schmidt & Son Co. (JFS) wholesale nursery in Oregon, grows 45 feet tall and 35 feet wide. Another JFS red maple is ‘Scarlet Sentinel.’ It has a more upright form and grows 40 feet tall and 20 feet wide. It works well for narrow spaces, but is not going to produce as much shade.

Rate of growth is also important. There is a temptation to plant a tree that will grow fast and produce shade quickly, such as a weeping willow, hybrid poplar, or silver maple. Resist the temptation. Fast growing shade trees tend to have massive invasive root systems that can interfere with septic systems, irrigation lines, and sewer lines, as well as raise driveways, walkways, patios, and even building foundations. Most fast growing trees also have weak wood that is prone to breakage and rot. Many also create excessive litter, are predisposed to insect pest problems, and are short-lived.

Heat tolerance is crucial in our region. It gets excruciatingly hot and sunny here during the summer. Not all trees are tolerant of heat. Most local nurseries carry shade trees that can reasonably tolerate the local summer weather, but heat tolerance must be checked when buying from big box stores or on-line. These sources may offer excellent trees that are not well adapted to our region.

Other characteristics to check when selecting a shade tree are tolerance to the alkaline soil that predominates in our region, potential insect and disease problems, litter problems, and seasonal interest.

I suppose you want me to stop dancing around and the answer the question. What shade trees would I recommend for our area? My favorites are the ones I have planted in my current and past landscapes. At the top of my list is ‘Dura-Heat’ river birch, Betula nigra. It is heat and drought tolerant and resists bronze birch borer, a troublesome boring insect that attacks birches. It also has a relatively fast rate of growth, buttery yellow fall color, and interesting apricot colored papery bark. My other “favs” include ‘October Glory’ and ‘Red Sunset’ red maple; ‘Autumn Blaze’, a red and silver maple hybrid; ‘Greenspire’ littleleaf linden; and red oak.

A shade tree is an investment of money and time. Do your homework and choose wisely.

This story was originally published April 1, 2017 at 3:45 PM with the headline "Garden Tips: Choose shade trees wisely."