The first 2 or 3 years are the most important period in the establishment of newly planted trees. Good cultural practices during this period help reduce transplant stress and create a favorable environment for tree growth.
The key to watering newly planted balled and burlapped and container-grown trees is to keep the plant's root-ball moist for several weeks after planting. Water newly planted trees every day for 4 or 5 days and then gradually reduce the frequency of watering. When watering, slowly apply water to the root-ball and the surrounding soil. A thorough watering every 7 to 10 days (in dry weather) should be sufficient 4 to 6 weeks after planting. Continue this watering schedule through summer and fall. Discontinue the watering of trees when the ground freezes in winter. Small trees usually require watering for 1 or 2 growing seasons. It may be necessary to periodically water large trees for 3 or 4 years.
To help conserve moisture, place 2 to 4 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 6 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.
It is generally not necessary to fertilize newly planted trees. Most Iowa soils can supply sufficient amounts of nutrients during establishment. If the trees are growing poorly 2 to 3 years after planting, fertilization may be beneficial. Poorly growing trees typically exhibit sparse foliage, yellow-green leaves, or short annual twig growth.
Trees utilize sugars and other carbohydrates manufactured by the foliage for plant growth. Therefore, avoid the temptation to heavily prune newly planted trees. Heavy pruning reduces the tree's ability to manufacture food and slows plant growth. Pruning of newly planted trees should be limited to 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 5 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 straps of canvas, polypropylene, rubber, or other materials to support the tree. If possible, remove the staking materials 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).
Newly planted trees require special care during establishment. However, the rewards for our efforts are healthy, attractive trees that provide us with many years of enjoyment.