Tree for confined courtyard

We live in Placitas, NM, and are looking for trees to plant within our courtyard. Our concern is that we plant something that will not affect the foundation or courtyard walls. We would like some shade for several windows that face east, southeast, and west. What would you recommend? The courtyard walls range from 10 feet away from the house to 18 feet.

Diane A.

Placitas, NM

You want a tree to provide shade in a small, confined courtyard. You are concerned about the foundation and the walls. These are valid concerns and create constraints in choosing which trees to use. A small tree or large shrub trained into tree form may be the best choice.

The New Mexico olive is one possibility. It has small, yellowish-green leaves and a light tan bark. It is a shrub but can be trained to form a tree about 15-feet high. It makes a nice multi-trunked small tree. There are male and female plants in this species. The male produces pollen, which may be of concern as an allergen causing hay fever. The female produces small fruits that can stain paving in the patio or be carried indoors to stain carpeting. These fruits will be attractive to birds, which may be desired, but their droppings may be undesirable.

The Japanese lilac is a small tree with large clusters of small white flowers in the spring. It lacks the perfume of the French lilac but does have a sweet smell. It has a dark bark and medium-sized dark green leaves.

The desert willow is another small tree. In time, it can become larger than the trees listed above. It should do well within the confines of the courtyard. It does not cast as dense a shade as the two plants mentioned above but creates a lighter shade. It produces a wealth of flowers in pink, burgundy, or white, which is attractive to hummingbirds.

The lilac chaste tree (Vitex) is another small tree that can be used to provide shade in a small courtyard. It has a very strong spicy fragrance when leaves or stems are bruised. You will probably not want to be brushing against it a lot.

Perhaps you like apples. Crabapples and fruiting apple trees may also be considered. Some crabapples are small enough, and fruiting apples on semi-dwarfing rootstocks may provide a tree of the proper size that will not damage foundations and courtyard walls. Other varieties of fruit trees may be worth considering if you want a tree that makes edible fruit as well as shade. They will also provide flowers in the spring. Apricots and other very early flowering fruit may flower too early in the warm environment of the courtyard, so they may not produce fruit. Later-flowering fruit trees are worth considering if you are not concerned about fruit falling onto the courtyard.

Another possibility, if you are willing to consider something other than a tree, is an arbor and a vine. This is a faster way to create shading and also allows for less shading and better heat gain in the winter. Various perennial or annual vines may be used, and the arbor can be very attractive.

Annual vines include morning glories, scarlet runner beans, and even gourds. They will provide no shade in the winter.

Perennial vines (most will need some pruning) include grapes, clematis, honeysuckle, silver lace vine, trumpet vine (very vigorous - be careful with this), and many others.

The vines are much less likely to have roots to worry you, but the small trees should also be safe for the foundation and wall if they are planted in the center of the area.

These are only a few of the choices. Check with your local nurseries for other ideas.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

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