Trees are a joyful addition to any home. They provide summer shade, year-round beauty, and are a vital habitat for birds and other wild creatures. They also store carbon, stabilize the soil and, of course, produce the very oxygen we need to breathe. In paved-over cities, they lower the air temperature in summer, mitigate surface-water flooding, block bitter winds and can even reduce noise pollution.
Long-lived and majestic, a tree may be planted in someone’s honor or memory, or to mark a child’s milestone birthday, thereby becoming a treasured reminder of a loved one. In short, planting a tree is a significant act, one that has a lasting impact on the garden, the environment, and one’s psyche. For all these reasons, it’s important to get it right.
When is the best time to plant a tree?
Plant in spring or fall. The cooler months of autumn and winter (in places where the ground doesn’t freeze) are the best time to plant a tree. Early spring is also good, but avoid summer because new trees can become stressed and even die when temperatures are high and the soil is dry.
Where is the best place to plant a tree?
Give your young tree space to grow to its mature size without bumping into your house or tangling with overhead power or telephone lines. Forgetting to take into account a tree’s mature size is a common mistake, and trees grow faster than you think. Plant smaller, ornamental trees at least 10 feet away from the house or utility lines. For larger shade trees, increase the distance to 15-20 feet.
© Pam Penick
How deep should the hole be?
When digging the perfect hole for tree planting – consider both depth and width, it's your tree’s new home, after all.
First, depth: A tree should be planted exactly as deep as the root ball’s height. This is because a tree’s surface roots need oxygen. If planted too deeply, or in soft, loose soil that settles over time, a tree ends up sitting too low and may eventually suffocate. Therefore, measure the tree’s root ball and dig only that deep and no deeper. Before measuring, remove the tree from its container so you are able to measure the root ball itself, and not all the way to the top of the container.
Next, width: The hole should be dug twice as wide as the root ball. That way, after you backfill around the new tree, it has nicely loosened soil, rather than hard-packed earth, in which to grow strong lateral roots.
In short, you want to dig a hole that's wide but not deep.
Free the Tree
A tree’s roots must be free to grow and spread, so remove its pot, or, if it’s wrapped in burlap and twine, cut that away completely and discard it. Now inspect the root ball. If the tree is root-bound, with visible roots wound tightly around the circumference, gently loosen the outer roots to encourage them to stop circling. Sever thicker circling roots if too rigid to loosen.
Next, lower the tree into the hole and check that the top of its root ball is at the same level as the surrounding soil. With the tree sitting in the hole, fill up the hole with water and let it soak into the soil. If it drains quickly, repeat a couple of times to moisten the soil and the root ball. Finally, backfill with excavated soil, never with potting soil or amendments, and lightly tamp into place. Settle the soil by watering deeply.
Make a Mulch Donut
Improper mulching can kill a tree by suffocating its surface roots or rotting the trunk. Never pile up a mound of mulch, volcano-style, around a tree’s trunk. Instead, encircle the trunk with a wide donut – a low berm – of mulch that’s the same diameter as the tree’s canopy. As the tree grows larger, so too should the mulch donut be expanded outward, keeping mulch pulled away from the trunk. The donut not only shades a tree’s roots but holds water long enough to soak in.
Ditch the Tree Stakes
Most young trees do not need to be staked. In the rare cases that they do – in windy climates, for example – remove the stakes 6 months later to encourage the tree to grow a strong root system that can hold itself upright. Do not tie staking wire tightly around a tree’s trunk, as this can kill a tree over time. Instead, pad the wire by running it through a segment of old garden hose, and loosely secure it so the tree sways (but doesn’t blow over) in the wind.
Water Regularly and Deeply
Newly planted trees need regular care to get them off to a good start. Water your new tree often for the first few weeks, keeping the soil moist. Thereafter, for the next two or three years, water deeply about once a week.
Which is best: native or non-native?
Choosing a tree that wants to grow where you live increases the odds that your tree will grow up strong and healthy for many decades to come. A native tree makes an excellent choice because it has evolved to thrive in your specific climate conditions – and local weather extremes, whether that’s freezing cold or extreme heat. Plus native trees provide much-needed habitat for beneficial wildlife.
But a well-adapted nonnative tree can be a good choice too, provided it grows well in your area and doesn’t have invasive tendencies. Check with your local nursery or search online for native or well-adapted trees for your region, and then cross-check that list against the invasive-plants list for your state, just to be sure.
For a large, long-lived tree that provides shade and majestic form, you can’t go wrong with an Oak. In the Southeast, Coastal Live Oak (Quercus virginiana) is a popular choice for large properties with plenty of room for the tree’s massive spreading limbs. Farther west, Escarpment Live Oak (Quercus fusiformis) is a similar but more drought-tolerant species, and on the West Coast, California Live Oak (Quercus agrifolia) thrives in the region’s rainless summers.
For an ornamental tree, or for shading a smaller lot typical of most suburban or urban neighborhoods, try spring-flowering Redbud (Cercis canadensis), a tree that’s native across much of the U.S.. Nonnative but well-adapted Crape Myrtle (Lagerstroemia spp.) is also a popular choice. It thrives in the South but can be widely grown as far north as zone 6.