Green Horizons

While nursery professionals recommend planting trees in late fall or early winter, for a variety of reasons most people associate this arbor activity with spring. If you are planning to plant a tree in the coming weeks, consider the following points.

Container grown seedlings are effective in urban tree plantings.

THINK BEFORE YOU PLANT. Place a wooden stake where each tree will be planted. Now step back and envision that fourfoot tree you are about to plant 20 years from now when it is 40 feet tall with a crown spread of 30 feet. Is it too close to the house? What about overhead power lines or underground water, gas or sewer lines? It is much easier to readjust stakes than planted trees.

BIGGER IS NOT BETTER. Homeowners often forego bare root seedlings because of their relatively small initial size compared to container-grown or balled and burlapped (B&B) trees. They want instant shade and worry-free mowing. But, bare root seedlings usually have a better balance between their shoots and roots. Oftentimes in a few short years they can equal or even surpass their big brothers and sisters. To be in some sort of balance, a B&B tree with a trunk diameter of 2" should have a soil ball that is at least 24" in diameter. Remember that the more instant shade gratification you desire, the bigger the tree, the bigger the soil ball, the bigger the expense, and the bigger the risk of failure.

SELECT A HEALTHY TREE. The bark should be intact and there should be no missing buds, particularly at the top of the main shoot. Missing terminal buds will create a "bushier" tree until one of the lateral branches assumes dominance and in most instances such trees will require corrective pruning to help the tree regain its natural shape. Bare root seedlings should have a fibrous root system. Container-grown and B&B trees should have a firm, symmetrical soil ball. Roots should occupy the entire volume of the soil ball, but should not be a solid mass of circling roots. This can lead to poor anchorage or even girdling (strangling) of the trunk (see GH Vol. 8, No.2 for more information on stem girdling roots).

PLANT IT RIGHT. For bare root seedlings dig a hole to fit the root system. Set at the same depth the tree grew in the nursery. Make sure to spread the roots out as you replace the soil. Fill the hole half full of soil and tamp well. Finish filling hole and tamp with feet.

For container-grown and B&B trees, dig the hole only as deep as the soil ball and 2-3 times wider than its diameter. If no roots larger than ˝" in diameter are found by probing 2" deep, on top of the ball, plant the tree 2-3" higher than the ball depth and remove the excess soil from the top of the ball. In addition you should loosen the surrounding soil 8-12" deep. This area should be equal to two to three times the diameter of the tree’s soil ball.

CLAY SOIL IS BAD. Clay soils do not foster good root growth. If you can form a soil "ribbon" greater than one inch long by pressing a moistened sample between your thumb and forefinger your soil contains too much clay. Peat moss and compost can help create a more favorable environment for root growth. But, these should be used in moderation (less than 20% of the soil volume) or else new roots will never want to venture out into the "real world".

KEEP TURFGRASS IN CHECK. Turfgrass roots compete strongly with tree roots for water and minerals. Establish a "weed-free" zone around your new tree as wide as is acceptable to you. Once the competition has been removedkeep it in check by mulching the area. Mulch should be no deeper than 2-4" and should be tapered so that it is less than 1" deep next to the trunk.

SECURE THE TREE. For container-grown and B & B trees staking is recommended if the tree is located in an area exposed to strong winds. However, secure the tree no higher than onethird of its height from the ground so that the top of the trunk can sway in the wind. To prevent injury to the tree trunk use rubber hose or specialty fabric straps to attach the tree to the supports.

WATER, BUT NOT TOO MUCH. The single most important survival factor of newly planted trees is soil moisture during the first few months after planting. It is equally important to keep in mind that over-watering new trees during hot conditions can kill them almost as quickly as a lack of water.

An effective way to deliver water is drip irrigation. The simplest method is to take a 5-gallon plastic bucket, drill 18-inch diameter holes in the sides near the bottom, and place the bucket next to the tree. This allows water to slowly trickle into the root zone. To estimate how much water to irrigate with, calculate the volume of the root zone in cubic feet and add about 2 gallons per cubic foot. For example, a tree bought in a 5-gallon container will have a volume of 1/2 cubic foot. So, unless it rains the tree should receive about one gallon of water three times per week.

Keeping these points in mind will help ensure that the time and money you invest today will pay off in many restful naps under the shade of tomorrow’s tree.