Choosing your tree - general considerations
For every landscaping need, there are Northern Virginia native trees that will fit the bill. If you only have time to do one thing to turn your yard into a wildlife sanctuary, let it be to plant a native tree.
The benefits of trees in general are obvious: in addition to improving property values and providing shade and year-round beauty, trees cool the environment, soak up greenhouse gases, and provide fruits and shelter for birds and other wildlife. But trees that are native to our area go far beyond that. Unlike those from other continents, a tree that is native to Virginia can support astonishing numbers of Virginia native insects. And insects – especially caterpillars – are what songbirds feed their babies. No native plants, no caterpillars; no caterpillars, no baby birds. And no butterflies either, of course!
Arlington's champion White Oak (Quercus alba)
When to plant
Fall planting has many advantages, as the roots can to start to establish before the summer heat and droughts start. Spring planting is preferable for some slow-to-establish species, such as Baldcypress, American Hornbeam, Magnolia, Sweetgum, Tulip Tree, willows, and Willow Oak. Conifers prefer the warm soils of summer or early fall.
Choosing the specimen
Trees do not like to grow in pots. A seedling that is growing in your yard already and that is getting enough sun is the most likely to prosper. Otherwise, buy the youngest example you can find, as that tree within a few years will exceed in growth and health of a more expensive, larger tree planted at the same time.
Inspect the plant carefully. The top should be healthy with a good structure, and the trunk should be free of wounds (unwrap it to check), but the roots are the potential trouble-makers. Do not buy it if the roots are growing out the bottom holes. Probe the soil – there should be large roots coming out from the plant near the surface. Carefully remove it from the pot – garden centers should expect you to do this – and make sure the roots are white or tan and there are no large roots at the edge of the pot. If several trees in pots are sitting in a group, do not buy the ones on the edge that are receiving direct sunlight: sun heats up black plastic and kills roots.
Ask the garden center if the tree was produced by air pruning, a superior method which prevents the formation of encircling roots.
How to plant a tree
Prepare trees grown in containers by “squaring the ball:” cut off the surface roots from top to bottom on all sides. This works much better than splaying or scoring the surface.
Dig a hole that has twice the diameter as the roots. Do not amend the soil! Place the tree in the hole with the root crown level with the surface. “Deglaze” the hole by roughing up the walls. Fill the hole with water and let it drain. Replace half the soil, and water to settle the soil. Finish filling the hole and water again. Add a ring of mulch, three feet in diameter and two to three inches deep. DO NOT pile mulch around the tree trunk – “mulch volcanoes” cause rot and can be home to mice and rats. Do not stake the tree unless absolutely necessary, and then only for one year at most.
Water with one gallon of water per inch of trunk caliper every other day for at least a month, then twice a week until established. Water around the edge of the planting hole to encourage roots to reach for the water. Trees become established in a year for every 1.5 inches of tree caliper. In other words, a tree with a two inch trunk will take 3 years to establish! Saving on work is another good reason to buy smaller trees.
Plan for shade
Choose the right size tree
Plan around obstacles
Shade trees - Red Maple (Acer rubrum), Tulip Tree (Liriodendron tulipifera), Black Sour Gum (Nyssa sylvatica), Shortleaf Pine (Pinus echinata), Loblolly Pine (Pinus taeda), Virginia Pine (Pinus virginiana), White Oak (Quercus alba), Swamp White Oak (Quercus bicolor), Southern Red Oak (Quercus falcata), Swamp Chestnut Oak (Quercus michauxii), Chestnut Oak (Quercus montana, Quercus prinus), Pin Oak (Quercus palustris), Willow Oak (Quercus phellos), Northern Red Oak (Quercus rubra), Post Oak (Quercus stellata), Baldcypress (Taxodium distichum)
Short trees - Eastern Redbud (Cercis canadensis), Downy Serviceberry (Amelanchier arborea), Canada Serviceberry (Amelanchier canadensis), Fringe Tree (Chionanthus virginicus), Flowering Dogwood (Cornus florida), Sweetbay Magnolia (Magnolia virginiana), Southern Wax Myrtle (Morella cerifera), American Wild Plum (Prunus americana), Chickasaw Plum (Prunus angustifolia)
Specimen trees - River Birch (Betula nigra), American Hornbeam (Carpinus caroliniana), American Beech (Fagus grandifolia), American Holly (Ilex opaca), Eastern Red Cedar (Juniperus virginiana)
Avoid soil compaction
Avoid tree litter on walking surfaces
Examples of Northern Virginia native trees for landscaping
Eastern Redbud (Cercis canadensis)