Choosing a tree
Author: Alyssa Zearley
Right tree, right place
Trees will live long, healthy lives if planted in a site that can support all of their needs. It’s not feasible to change the site to match the tree - you must choose an appropriate tree for your site! Once you know the site’s light, moisture, pH, and soil quality and have determined what size tree you need, use the Tree Grids (linked below) to find appropriate species.
- Full sun: 6+ hours a day and light between 10-3pm
- Part shade: 3-6 hours a day
- Shade: 0-3 hours direct sunlight a day
- Dry: Does the soil have a lot of sand in it and get so dry that grass has trouble growing?
- Wet: Is this spot soggy in the winter and spring?
- Medium: Neither wet nor dry as described above
Most soils in NEO are slightly acidic. Sometimes construction fill (like on vacant lots and new development) is basic. If you have pre-WWII construction or are planting on undeveloped land, assume the soil is slightly acidic. If you have post-WWII construction, consider a soil test if you want to plant an acid-loving species like tupelo or pin oak. If you are planting on a vacant lot or new construction, get a soil test from a laboratory.
Soil properties like organic matter, compaction, and biological activity influence soil quality and its ability to support a range of plant species. Sites with higher soil quality can support sensitive species, while only a few, tough trees can thrive on sites with poor quality soil. The Tree Grids (linked below) separate trees into three soil quality categories. “Good” means the soil must be good quality, “Intermediate” trees can handle intermediate quality sites, while “Poor” trees can tolerate poor soil. Given changing construction practices, older homes have better soil quality than newer ones. As a rule of thumb, if the property was built pre-WWII, use “Good” or “Intermediate” trees. If property was built after WWII but before the 1980’s, use “Intermediate” trees. Use “Poor” trees for tough spots like newly developed vacant lots and recent construction. If the site currently doesn’t support grass or weed growth, amend the soil with compost and choose a species that can tolerate Poor sites (check out Virginia Tech’s resource on Soil Profile Rebuilding).
Siting and sizing
- Plant the largest tree possible for the space. Large trees provide much more shade, stormwater, pollution, and wildlife benefits than small trees, and they tend to live longer.
- Large trees have a canopy width of 30-50’, medium trees have a canopy width of 15-30’ and small trees 10-20’. Use mortonarb.org or wildflower.org to get specific widths and information about each species.
- Near structures and power lines, leave space for at least ½ of mature canopy width (i.e. a 50’ wide tree should be 25’ from a house).
- Plant trees in groups to reduce the risks from storm damage. Trees in groups can be the same or different species and sizes. Space small trees 5-10’ apart, medium trees 10-20’ apart, and large trees 20-30’ apart.
- If planting near a sidewalk or driveway, plant the tree at least 5’ (for small and medium trees) or 10’ (for large trees) away to avoid concrete lifting and allow structural roots enough room to anchor the tree
- Don’t plant on treelawns without permission or a permit. Plant at least 25’ from a street corner
Using the tree grids
- Choose the Good, Intermediate or Poor grid based on your site's soil quality.
- Select the column with your soil moisture, and the row with your sun exposure. The trees in the intersecting box are a good fit for your site.
- Trees with an (A) need acid soil and with a (B) need basic soil.
- Special considerations: only plant disease-resistant elms (R). Don’t plant a white group oak within 50’ of each other (white, bur, swamp white, chestnut, chinquapin) to prevent the spread of oak wilt. Don’t plant red group oaks within 50’ or each other (scarlet, pin, red, shingle).
Links to the tree grids
Planting your tree
Refer to our tree planting guide to give your tree a shot at a long, healthy life.