Would you like to add a tree or shrub to your garden? You could just go to the garden center and buy whatever they have for sale, but you’ll make a better choice if you think it through in advance.

“Trees and shrubs live for a long time, so when you plant one, it’s a commitment,” said Julie Janoski, Plant Clinic manager at The Morton Arboretum in Lisle. To be sure you’re ready for that commitment and to help you pick the right plant, ask yourself some questions:

What do you want this plant to do? Do you want it to screen the neighbors’ patio? Create a focal point in the yard? Make the garden more interesting in winter? Give you something attractive to look at from the kitchen window? Do you want a tree that will cast shade, once it’s grown large?

What are your must-haves? Do you want spring flowers? Autumn color? Four-season interest? Are you looking for an evergreen? Do you want a native tree to support native wildlife?

What do you want to avoid? If you don’t like pruning, it may be important to choose a shrub that stays at a compact size. If you don’t like fruit falling on your patio, you’ll need to look for a cultivar, or cultivated variety, that is sterile and doesn’t form fruit.

Where will you put it? The location may limit what you can plant. “Trees and shrubs need space for their roots as well as their branches,” Janoski said. “The soil in your planting site and the amount of sunlight that reaches that site every day are also important factors in which plant you choose.”

How much space is available? Remember that any tree or shrub will get wider and taller as it grows. “Don’t just think of the spot where you’ll dig the hole,” she said. “Measure the space around that spot to figure out how wide and tall you can afford for the plant to get in a few years.”

What is the soil like? Every kind of tree and shrub is suited to certain kinds of soil. If yours is sticky clay, you will need a different plant than you would for a sandy site. If the site is often wet, so it’s squishy when you walk on it or you often see standing water after rain, it’s not a good place for an evergreen tree or shrub. “You’re trying to find a plant that can live in the environment you have,” she said.

What is already growing nearby? Some plants, such as black walnut and buckthorn, make it hard for other plants to grow near them. You’ll also want to avoid trees and shrubs that are already overplanted. “It’s not a good idea to choose the same kind of tree that is already growing in front of most houses on your block,” Janoski said.

Once you’ve gathered information about the site, you can start looking for a specific kind of tree or shrub. The Arboretum’s website (mortonarb.org/plantadvice) offers a wide range of information on trees and shrubs that are suitable for various sites and purposes. The Plant Clinic (plantclinic@mortonarb.org) can help you narrow down your choices to a few good possibilities. Then you can start seeking them out in garden centers or nurseries.

“There will never be a perfect plant that does everything you want,” Janoski said. “There are always trade-offs. We can help you understand the pros and cons of each kind of plant you’re interested in.”

Still, you will always have choices. “There are so many trees and shrubs available that you’re sure to find something that will give you joy for years to come,” she said.

For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plantadvice or plant clinic@mortonarb.org). Beth Botts is a staff writer at the Arboretum.