When choosing a tree, consider its mature size
Nurseries and home centers have a bounty of trees and shrubs in early fall, and it’s a fine time to plant them. Just be sure you choose one that won’t grow way too big in a few years, said Julie Janoski, manager of the Plant Clinic at the Morton Arboretum in Lisle.
“It’s easy to be deceived when you’re shopping,” she said. “Looking at those cute little plants in their pots, you may never imagine how tall and how wide they will get.”
Choosing a tree or shrub without considering its mature size is a recipe for big trouble, Janoski said.
You may buy a slender young sapling, but if you plant it too close to the house, it can grow to threaten the foundation. A too-big shrub can block your whole front window and darken the house. Sprawling shrubs may block the sidewalk or the front door.
Sometimes homeowners can visualize how tall a tree may grow, but they fail to consider that it also will get wider, Janoski said. This lack of foresight can be especially costly with evergreens. “Evergreen trees have branches all the way to the ground, and the branches at the bottom get longer all the time,” she said.
If you choose plants that are genetically programmed to grow too big for your yard, you may find yourself pruning them constantly to keep them under control. If you plant a tree where there just isn’t space, you may have to cut it down in just a few years to solve problems.
How can you avoid this trap? Before you go shopping, take a hard look at the place where you plan to plant, Janoski said. Consider how much of the lawn or garden bed you are willing to allow for a mature tree or shrub.
Look up. Is the site close to the roofline? Is there an overhead power or telephone line nearby? In that case, plan on a tree or shrub that will get no more than 20 feet tall. Otherwise, utility crews will be forced to prune it severely for safety’s sake.
Once you’ve decided how much space you can allow for the width of your tree or shrub, mark the span and measure it. Measure the height you can allow for shrubs. The height of your house can help you estimate how tall a tree would be appropriate for your yard.
Write those numbers down and take them to the garden center when you shop for a plant. The mature size and width of every plant will be stated on the label. “Read that label, and take those numbers seriously,” Janoski said.
Check the label of each plant you buy. It may be the only way to tell plants apart. “When plants are small, they can all look alike,” she said. “But they may have very different growth rates and go in totally different directions in a couple of years.”
Even different cultivars, or cultivated varieties, of the same species can diverge sharply as they get older. Some cultivars of yew, a popular shadetolerant shrub, will always stay low to the ground, but others can grow to be 40 feet tall. Yet in a pot at the home center, they look identical, except for the label.
Does this seem too confusing? Take pictures of the labels of some plants you’re considering and use them to consult the Plant Clinic before you buy.
For tree and plant advice, contact the Arboretum’s Plant Clinic (630-719-2424 or plantclinic@morton arb.org).
Beth Botts is a staff writer at the Morton Arboretum in Lisle (www.mortonarb.org).