A beginner’s guide to selecting, planting, and protecting a new tree

The following is an excerpt of Now Is the Time for Trees by Dan Lambe.

So, you’ve done your homework and determined what you want in a tree and how you want it to contribute to your landscape. You’ve familiarized yourself with the nature of your growing region and assessed the specific conditions of your planting site. You’ve considered all the ways in which a tree can create a more comfortable environment, providing tangible environmental and economic benefits. You’ve learned about the different parts of a tree and how each of them function. Best of all, you’ve gotten a glimpse of the many beautiful types of trees that can enhance your landscape and transform it into a sanctuary that enriches life for everyone in your household and even your larger community. Now comes the really exciting part—selecting a healthy tree and planting it!

Good tree care starts with choosing a healthy tree. Remember, your tree will be with you for years, maybe even generations, to come. Here’s what to look for when purchasing a tree to ensure that it gets off to a healthy start and can provide a lifetime of benefits.

Shopping for trees

When shopping for trees at the nursery, choosing a tree with a strong cen-tral leader is especially important for shade trees. Avoid trees with multiple leaders. Low branches, while temporary, help promote growth and protect plants from sun scald—so be sure they look healthy as well.

At the nursery, you’ll find plants have been categorized based on how they were produced, harvested, and prepared for retail. The various options, which include container-grown trees, ball-and-burlap specimens, and bare root plants, require different handling and planting techniques.

Container-grown trees have spent their entire nursery life growing in a container. A well-tended container-grown tree has been carefully monitored and moved up into gradually larger containers as the plant grows. If a tree outgrows its container without being moved up, its roots will begin to circle or twist within the container, which may lead to girdling, or strangling the plant’s vascular system, and root die-off. 

It’s perfectly acceptable to gently remove a tree from its container at the nursery to inspect the roots. Roots will continue to grow in the direction they are already pointing. Fine circling roots may be untangled or cut away at planting. Larger, woody roots may be straightened if they are still flexible.

Container-grown trees may be planted at any point in the year provided the soil is workable and not frozen, knowing that the hottest days will require frequent watering. 

Ball-and-burlap trees are grown in the ground until they have achieved targeted size. When a tree is ready to be moved, the root ball is dug along with a mass of surrounding soil, then wrapped in burlap in preparation for transporting and resale. Larger root balls may be further supported by a wire basket cage over the burlap.

When purchasing a ball-and-burlap tree, look for a firm root ball that is securely tied. It’s critically important that the root ball is large enough to support the maturity of the tree; it should be about 10 to 12 inches wide for every 1 inch of trunk diameter measured at a point 6 inches above the root collar. Avoid buying plants with damaged or compressed root balls; rounded or misshapen root balls may indicate woody root loss.

Always carry a ball-and-burlap tree while supporting the root ball. Moving or lifting the tree by its trunk may cause the root ball to separate from the trunk.

Because ball-and-burlap trees are dug from a nursery field, most of the root system has been removed. Don’t worry, though, they will quickly regrow a functioning root system. But that means ball-and-burlap trees should be planted during cooler weather, avoiding the hottest, most stressful time of year.

Preparation is everything

After making sure that you select a healthy, well-formed tree, properly preparing your planting site is the best thing you can do to get your tree off toa strong start. 

Before you plant, make sure your tree is thoroughly hydrated by watering the container or root ball several hours before proceeding; it’s very difficult to rewet a large root ball that has dried out after the tree has been planted.

When planting a tree into a lawn, remove a circle of grass at least 3 feet in diameter where the tree will go to reduce competition between turf and fine tree roots. In areas where the lawn is the primary design feature, select small trees with open canopies that will allow sunlight to penetrate to the ground. Remove turf altogether where surface tree roots—most prevalent where topsoil is compacted—may be damaged in the future by mowing.

Planting container-grown and ball-and-burlap trees

Gather your tools. You’ll need a measuring tape or ruler to help guide you in digging your planting hole and placing the root ball at the proper depth.The majority of a young tree’s roots develop in the top 12 inches of soil,where water and oxygen are most accessible. If the tree is planted too deeply, new roots will have difficulty developing due to a lack of oxygen. In poorly drained or heavy clay soils, trees can be planted with the base of the root collar above grade—1 inch for every inch of trunk diameter.

• Measure the root ball, either in the container or ball-and-burlap, to determine how wide and how deep of a planting hole to dig for your tree.

• Dig a broad, shallow planting hole with gently sloping sides that is three to four times wider than the diameter of the root mass and the same depth. Mounding removed soil on a tarp makes backfilling and clean-up a snap. Further loosening the soil on the sloping sides of the plantinghole allows roots to easily expand and establish faster, but don’t disturb soil at the bottom of the hole.

• If you are planting a containerized tree, prepare the root ball for planting. Sharply tap the outside of the container to loosen and remove the root ball from the container, being careful to keep the soil around the roots intact. You may need to slice the plastic pot, from lip to bottom, to facilitate loosening the root ball. To remedy circling or congested roots ,use a sharp knife to carefully slice an X across the bottom of the root balland to make four vertical slices along the sides of the soil mass. This will encourage roots to branch at the point where they were cut and move out into the surrounding soil.

• Set your tree in the middle of the planting hole. Remember to lift by supporting the root ball. Don’t pull on the trunk or the roots may separate from the tree. Double check to make sure that the planting holehas been dug to the proper depth and no deeper. The root collar should be just above soil level; if it’s too low, compact soil beneath the root ball to raise it to the correct level.

• For ball-and-burlap trees, once the root ball is in position, use wire cutters to cut vertically up the side of the wire basket and peel it away.Remove all rope or twine from the root ball as well as any nails that may be holding the burlap together. Pull the burlap away from the top and sides of the root ball and cut away any loose material. Don’t worry about regular burlap under the root ball, because it will naturally break down over time. But vinyl or coated burlap should be removed completely.

• Straighten the tree in the hole. Before backfilling, have someone view the tree from several directions to confirm that the tree is straight. As you can imagine, it is very difficult to reposition a tree once it’s planted.

• Replace the soil, while firmly but gently tamping the original soil around the base of the root ball to stabilize it. Do not amend the backfill or apply fertilizer at planting time. Keep backfilling until the soil is just below the root collar.

• Create a water-holding basin around the tree by building up a ring of soil—or flip over the grass you removed to make room for the tree and build a ring with that—and then water thoroughly to settle roots and eliminate air pockets that may cause roots to dry out.

• Spread protective mulch 2 to 4 inches deep in a 3-foot diameter area around the base of the tree, but not touching the trunk.

• Other than removing dead and broken limbs, avoid pruning your tree at planting.

Tending to your newly planted tree

How you care for your tree in its first and early years of life will affect its shape, strength, and even its life span. It’s hard to get a tree to its second year if it doesn’t live through its first. The best thing you can do for a newly planted tree is to keep it watered well during the first year after planting.You’ll want to water it weekly so that the soil stays moist, but not soggy. A simple trick is to stick your thumb in the soil. If it comes out dry or dusty,the tree needs water. If it comes out muddy, then it doesn’t need water.

In dry spells, water the entire area within a little beyond the drip line to keep soil and mulch moist but not soggy; avoid waterlogged conditions.Water the tree about once a week, enough to have the soil damp to a depth of1 to 3 feet, depending on the tree’s size. Mulching with wood chips, bark, or other organic material helps retain soil moisture and reduces competition from weeds and grass.

Studies have shown that trees establish more quickly and develop stronger trunks and root systems if they are not staked at the time of planting.However, staking may be required for bare root stock and container grown conifers or when planting on windy sites. Stakes can also prevent lawn mower damage. If you decide to stake, use two opposing flexible straps placed as low on the tree as possible to perform the task. The tree should be able to sway in the wind—without the root ball moving— which aids trunk and root development. Check support staking regularly for damage to the trunk and remove all straps and ties after the first year of growth.

It’s important that tree roots expand and establish in the native soil.Soil properties are extremely difficult to change with an amendment of any kind. Do not add potting soil or organic or chemical fertilizer on your newly planted trees, which can cause water logging or burn roots.

Keep vines away from newly planted trees, and remove all tags and labels.Not only are labels an eyesore in the landscape, leaving them in place can strangle limbs as the tree grows. After you remove them, keep labels some-where safe for future reference.

Dan Lambe is the CEO of the Arbor Day Foundation.

Excerpted from Now Is the Time for Trees by Dan Lambe, published by Timber Press. All other rights reserved.