“The best time to plant a tree is twenty years ago. The second-best time is now.”

This is one of many hoary bits of wisdom about gardening. Instead of reviewing more such bits, let’s consider how to select a landscape tree during this year’s dormant period.

The New Sunset Western Garden Book (2012)—always a useful reference—lists four categories of garden trees that not yield edible fruits: patio, shade, flowering and fall foliage.

Patio trees are primarily ornamental, and relatively small and free of troublesome behavior.  Shade trees are larger than patio trees, and typically deciduous. Flowering trees and fall foliage trees also provide shade, but they are selected primarily for their ornamental value.

Landscape trees, depending on size, could be dug as bare root specimens, grown in a plastic container wooden box, or dug and “balled & burlapped.” The larger specimens can be expensive and very heavy to manage, but desirable for achieving an immediate effect in the garden.

Once the gardener has decided on the landscape purpose of the tree and its size at the time of purchase, there are three major criteria for selecting a specific tree.

First, know the tree’s mature size and ensure that it will not outgrow the location you have in mind. The most common error in selecting and planting a tree is to locate it where it eventually will grow to become unwelcome. It might crowd a pathway or driveway, or even the residence. Its might harm other plants by blocking the sunlight with its leaves or absorbing the available moisture with its roots. Choose a tree that will be a good neighbor.

Second, for containerized trees, confirm that the roots have had ample room to grow normally. A tree’s roots should fill no more than 50% of the container; otherwise, the tree could become root-bound, with a long-term threat to its life. I once had a tree service install a large Santa Cruz Cypress (Cupressus abramsiana), an endangered species, only to have it topple months later during a mild windstorm. I discovered that it was severely root-bound, so that its roots could not anchor the tree effectively. Before buying a tree, examine its root structure by pulling the tree from its container.

Thirdly, ensure that the tree’s future location has at least six hours per day of exposure to sunlight, which almost all trees require for health and normal growth. I planted two identical Chilean Myrtle (Luma apiculata) trees, one in full sun, and one too close to an American Sycamore (Platanus occidentalis). Today, the tree growing in the sun is about three times the height of the other tree.

Choose your new landscape tree with care!

More

The April 2014 issue of Fine Gardening magazine (already on the newsstands and in libraries!) includes an excellent article on this topic. “How to Buy a Tree” by Ed Gregan presents a most thorough discussion of problems that might be encountered with a nursery tree.

I hasten to add that reputable nurseries and garden centers won’t offer trees with significant shortcomings. The owners and managers of well-run retail garden outlets are good people who respect plants and gardening.

Still, it’s possible for a problem to slip through and you could take home a tree that won’t thrive as you, the original grower and the tree itself would prefer. The most common problem is a tree that has become root-bound, after sitting in the garden center or nursery too long. This condition obviously could develop while the manager was not looking!

Ed Gregan’s article is not available online (except for Fine Gardening subscribers), so I can only list his bullet points (below), but you’ll need to read the article for the full story.

1. Ensure grant points are smaller than a dime
2. Walk away if there are wounds
3. Pull off the pot to assess the roots
4. Strive for a single straight leader
5. Check under the trunk protector
6. Look for signs of trouble
7. Watch out for “coat hangers”
8. Avoid poor crotches
9. Avoid even numbers for multistems
10. If the flare is too high or too low, the tree is a no
11. Give the ball a thorough inspection
12. Check for even spacing with clumps