By James Romer
Iowa Master Gardener Coordinator
Iowa State University Extension
Trees are an essential part of the home landscape. Trees provide beauty, shade and habitat for wildlife. Besides being beautiful additions to the landscape, trees also can screen unsightly views, provide privacy, reduce noise pollution and lower utility bills.
How Trees are Sold
The most common way to establish trees in the home landscape is to purchase balled and burlapped or container-grown plants at local garden centers and nurseries. Balled and burlapped (B&B) trees are dug with balls of soil around their roots. The rootballs are wrapped in burlap and held in place with twine or nails. Large trees are placed in wire baskets for additional support. Balled and burlapped trees can be successfully planted from spring to fall.
Container-grown trees have been grown in containers for one or more seasons. As a result, container-grown plants have well developed root systems. The planting season for container-grown stock is the same as for balled and burlapped material. Generally, container-grown trees are smaller in size and lower in price in comparison to balled and burlapped stock.
Planting a Tree
Poorly drained sites are difficult locations for many trees. When selecting trees for these sites, choose trees that can tolerate poorly drained conditions. When planting, the depth of the planting hole should be approximately two-thirds of the height of the rootball. When placed in the hole, the top one-third of the soil ball should be above the surrounding soil. When backfilling, place soil to the top of the rootball and gradually slope it down to the surrounding soil line.
To successfully establish trees in the home landscape, it's important to follow proper planting techniques. For balled and burlapped trees, dig a hole two to three times wider than the diameter of the tree's rootball. The depth of the hole should be two or three inches less than the height of the rootball. Slope the sides of the hole so the top of the hole is several inches wider than the bottom. (This technique also can be used for container-grown trees.)
Next, grasping the tree's rootball, carefully lower the tree into the hole. The top of the rootball should be approximately two or three inches above the surrounding soil line. Make sure the trunk is straight. Then, begin backfilling with the original soil. Do not add compost, peat or other organic materials to the soil. Gently firm the backfill soil in the hole with your hands.
When the planting hole is one-half full, cut and remove all twine. Also, cut away and remove the burlap on the top one-third to one-half of the root ball. If the rootball is in a wire basket, remove the top one-third to one-half of the basket. Completely fill the remainder of the hole with soil. Place soil up to the top of the rootball and gradually slope it down to the surrounding soil line. When finished the trunk should widen or flare just above the soil line. The tree trunk should not resemble a utility pole, but should look like that favorite pair of bell bottom jeans you may have in the back of your closet. The last step is to thoroughly water the tree.
Once the hole has been prepared for container-grown trees, as earlier described for balled and burlapped trees, carefully lay the tree on its side. Tap the sides of the container to loosen the soil ball from the container, and then slide the tree out of its container.
Sometimes it is necessary to cut off the containers of large, container-grown trees. Begin by cutting off the bottom of the container. Place the tree in the hole, then, cut away the sides of the container. All containers should be removed, even supposedly plantable containers. If the sides of the soil ball are a mass of roots, make several 1/2-inch-deep cuts up the sides of the soil ball with a sharp knife. Also, make a 1/2-inch-deep, x-shaped cut on the bottom of the soil ball. Carefully place the tree in the hole. Remember, the top of the soil ball should be approximately two or three inches above the surrounding soil. In poorly drained sites, the top one-third of the soil ball should stick above the surrounding soil. Gradually fill the hole with soil. With each new addition of soil, firm it in place with your hands. Once planted, water thoroughly.
Tree Care and Maintenance in the Landscape
Newly planted trees need water, mulch and care for a couple of years after planting. The key to watering newly planted trees is to check the moisture status of the plant's rootball frequently. Since the roots of newly planted trees are initially confined to the plant's rootball, newly planted trees should be watered when the rootball (not the surrounding soil) begins to dry out.
To water the rootball, slowly apply water to the base of the tree. The frequency of watering can be reduced and the watering area enlarged as the tree's root system begins to grow into the surrounding soil. Small trees usually require watering for one or two growing seasons. It may be necessary to water large trees for three or four years.
To help conserve moisture, place two to four inches of mulch, such as wood chips or shredded bark, around trees. Mulches also help control weeds, moderate soil temperatures and reduce the risk of mechanical damage to tree trunks from errant lawnmowers and string-trimmers. When mulching trees, do not place mulch against the tree's trunk. Keep the mulch at least six inches away from the trunk of the tree. Mulch piled against the tree trunk may create favorable conditions for fungal cankers, root rots, insects and rodents.
Trees use sugars and other carbohydrates manufactured by the foliage for plant growth. Therefore, avoid the temptation to severely prune newly planted trees. Severe pruning reduces the tree's ability to manufacture food and actually slows plant growth. Newly planted trees require only corrective pruning. Remove structural defects, such as double leaders and dead, broken or crossing branches. Retain most of the lower branches to help stabilize the tree. The lower branches also provide food for the growing tree. Gradually remove the lower limbs as the tree grows during the first five to 10 years.
Staking is not required for most newly planted trees. However, top-heavy trees and those planted in windy, exposed sites may require staking. If staking is necessary, allow the trunk to move or sway for proper trunk and root development. To prevent damage to the trunk, use strong, wide strips of canvas, rubber or other materials to support the tree. Remove the stakes as soon as possible. In most cases, stakes can be safely removed after one growing season.
Wrapping protective materials around the trunks of newly planted trees is usually not necessary. There appears to be little or no benefit to tree wraps. If you do decide to use a tree wrap, place it around the tree in fall (November) and promptly remove it the following spring (April).
It generally is not necessary to fertilize newly planted trees. Most Iowa soils can supply sufficient amounts of nutrients during establishment. If the trees are growing poorly two to three years after planting, fertilization may be beneficial. Poorly growing trees often exhibit sparse foliage, yellow-green leaves or short annual twig growth.
Following these planting and after planting steps will increase the likelihood of healthy, happy trees in your yard for years to come.
James Romer, Horticulture, (515) 294-2336, firstname.lastname@example.org