How to plant a tree
'"Right Tree, Right Place’ should take into account the mature size of the tree, not the size you want it to be, as well as ensuring the soil, water, sunlight and climate factors are all favorable for the tree species you are planting,” says Wes Kocher of the ISA. (All photos by Mike LaFollette)
Planting a tree is an easy task, but it takes more preparation and skill than you might think. Many people assume it’s so easy that they overlook basic planting techniques, potentially setting their trees up for failure.
All trees have needs, such as specific sunlight and water requirements. An improperly placed tree can grow into a home’s foundation, while a tree planted too deep is susceptible to disease and poor health.
So, before you go out and plant that maple tree underneath the power lines, consider the following tree-planting tips.
When to plant a tree
Spring seems like the perfect time to plant a tree, right? It’s when plant growth explodes and homeowners start sprucing up their landscapes.
However, the International Society of Arboriculture, a non-profit organization that promotes the benefit of trees and professional practice of arboriculture, says the ideal time to plant a tree is actually in the dormant season -- in the fall after leaf drop or in early spring. The cooler temperatures reduce stress on the tree because roots can establish before spring rains and high temperatures spur new growth.
But it doesn’t mean you can’t plant a tree during the spring or summer months. Arbor Day, when many trees are planted, doesn’t even occur until the last Friday in April, well after spring has sprung. The ISA says trees properly cared for can be planted throughout the growing season.
Buying trees from a nursery
To avoid problems down the road, it’s important to purchase a healthy tree. A high-quality tree should establish more quickly after transplanting, and will be more likely to fight off disease and survive heavy storms.
Avoid trees with crushed or circling roots or obvious wounds on the trunk. Look for a tree with one, dominant trunk and a uniform canopy. If the tree is staked in the nursery, remove the stake to ensure the tree can stand on its own.
Trees are usually sold as bare root or in a root ball or container. Bare-root trees should have a visible, fibrous root system that is moist and not dried out. If purchasing a tree with a root ball, make sure that the ball is firm and flat on top. The ball should be 10 to 12 times the size of the diameter of the trunk. When purchasing a tree in a container, watch out for roots that have grown into the container.
If the tree is sold in a container or root ball, make sure the trunk flare is visible. The trunk flare is the bulge where the trunk connects with the top layer of roots. If the flare is buried in the root ball, it can cut off oxygen to the tree or cause stem-girdling roots to grow around the trunk.
Where to plant a tree
“The mantra of ‘Right Tree, Right Place’ cannot be overstated,” says Wes Kocher, Technical Resource Manager for the ISA. “It is often difficult for homeowners to visualize the small tree they are planting will become an 80-foot giant, but the mature size of a tree must be fully taken into account.”
Avoid planting trees that will grow large under power lines or other trees. Kocher says trees planted too close to foundations, driveways or sidewalks can cause concrete to crack and buckle. He recommends ensuring all trees are planted at least four feet from the nearest conflict.
“One caveat to this consideration is the shading benefit trees can have for homes -- reducing summertime cooling costs,” he says. “The closer to a home a tree is, the more shade it will cast on the roof and windows. Homeowners should carefully consider the benefits and potential conflicts before deciding on a final location.”
Kocher says trees have the same needs as other plants and should be planted where the species will thrive. “Planting trees under the conditions preferred by each species will reduce the need for watering, fertilizing, pruning and pest management,” he says.
Once you’ve scouted a location, call 811 to schedule an underground utility inspection. The service is available nationwide at no cost to the homeowner. Otherwise, you risk digging through a utility line, potentially knocking out power to your neighborhood.
Start preparing your location by removing the top layer of sod. Use a garden spade or sod cutter to expose the dirt below.
“Dig the planting hole shallow and wide instead of narrow and deep,” Kocher says. “The loose soil used to fill the shallow, wide hole provides light aerated soil for the roots to grow into, and the shallow depth ensures the tree won't be planted too deep.”
The ISA says a young tree’s root system will develop in the top 12 inches of soil. If a tree is planted too deep, the roots will have trouble developing due to a lack of oxygen, which can negatively affect growth rate and increase susceptibility to diseases.
Remove any container or wrappings before placing the tree in the hole. For trees in plastic containers, cut away the container instead of pulling the tree out. Always hold a tree from the bottom and not by its trunk.
You know you’ve dug your hole to the proper depth if the trunk flare sits 2 to 3 inches above ground level. Arborists say it’s always better to plant a tree a little too high than too deep.
Carefully backfill the hole using the soil you removed. Add a few inches of soil at a time and pack it firmly with your hands to remove air pockets. Add water with each layer of soil to help it settle.
After filling the hole, check to make sure the root flare is visible and not buried below the surface. If the tree looks like a pole sticking out of the ground, it’s buried too deep.
Watering and maintenance tips
Add mulch around the base of the trunk to a height of 3 inches, but don’t allow it to actually touch the trunk. Mulch helps to preserve moisture while reducing temperature fluctuations in the soil. Avoid creating a mulch volcano around the trunk because the moisture can actually cause it to rot.
“Be sure to water newly planted trees thoroughly and often,” Kocher says. “Watering around the tree is good, but be sure to water close to the trunk to ensure the root ball is saturated. The soil at the site could have very good moisture levels, but the root ball could be dried out. And since that is where all the roots are for the first year after planting, that area needs to be well watered.”
He recommends a deep watering every week unless there is significant rain of more than one-half inch.
What could go wrong?
Transplant shock is the most likely problem you’ll face when planting a tree. The ISA says a bare root or balled tree’s root system has already been reduced by 90 to 95 percent of its original size, and the trauma associated with transporting and planting the tree can cause transplant shock.
Symptoms of transplant shock include wilted leaves and slow growth. According to the ISA, “Proper site preparation before and during planting coupled with good follow-up care reduces the amount of time the plant experiences transplant shock and allows the tree to quickly establish in its new location.”
For more information, please visit the Angie’s List Guide to Tree Care and Services.