If you’re not sure whether the plant is a small tree or a shrub, or whether it is a perennial or a ground cover, check both boxes.

You can check more than one box. For example, to see what plant might fit under a power line, you might check both “large shrub” and “compact tree.”

These refer to the US Department of Agriculture’s Plant Hardiness Zone Maps (planthardiness.ars.usda.gov), which divides the country into regions based on their average low winter temperature range. Plants are assigned to hardiness zones based on the low temperatures they have been found to tolerate.

Choose “deciduous” for trees that lose their leaves seasonally, and “evergreen” for trees with foliage year-round.

If you are not sure how much daylight there is in the place where you plan to put the plant, check all the boxes you think might apply.

Choose the type of soil you have to find plants suited to it.

To find plants that can tolerate less than perfect growing conditions, click the boxes that apply to your site.

If you check “North America,” the results list will include plants native to Illinois and to the Chicago area, as well as the rest of the continent. If you choose “Chicago area,” the results list will include only plants native to northeastern Illinois and northwestern Indiana, based on “Plants of the Chicago Region” by Floyd Swink and Gerould Wilhelm.

City parkway: Usually publicly controlled property adjacent and parallel to the roadway. Typically have high exposure to stressors (road pollutants, limited soil volume, dry soils). Widths vary.

Residential and parks: Open parcels of land, including commercial and industrial campuses. Typically have regular maintenance and fewer stressors than other urban sites.

Restricted sites: Openings in sidewalks and other pavements without soil under the pavement designed to support root growth. Although some trees tolerate restricted planting sites, growth will be restricted in less than 20 years if there is less than 200 square feet of open soil around them. Smaller spaces will reduce growth sooner and to a greater extent.

Under utility lines: Only plant trees with mature heights less than 25 feet under utility lines.

Wide median: Land in the center of a roadway. Typically have highest exposure to stressors (road pollutants, limited soil volume, dry soils), though medians come in many shapes and sizes.

These boxes refer to the time of year that the plant is most attractive. For example, a tree with lovely fall color is most attractive in the fall, while a flowering shrub may be at it most attractive in spring or summer. Many plants are interesting in multiple seasons for different reasons, such as interesting bark in winter but flowers in summer. You can check multiple boxes.

Narrow your search by choosing the flower color or fragrance of the tree or plant.

Some terms will apply better to trees (“oval”) and others will apply better to shrubs (“creeping”).

Growth rates vary by plant type. For example, for trees “slow” indicates less than 10 inches per year, “moderate” is 10-20 inches per year, and a “fast” growing tree is more than 20 inches per year.