Garden Maintenance - Tree Care |
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Fall Tree Care
Fertilizing a Tree
Fall Tree Care
The attention young trees need in Fall
Bonnie Lee Appleton
For the past several years the retail nursery industry has promoted the idea that "Fall is for Planting." While I agree that in much of our country fall is an excellent time to plant trees and shrubs, in many cases I think the best use of fall time is "unplanting."
Unplanting? OK, I am being a little tongue in cheek. I don't mean to literally dig a plant out of the ground. What I'm talking about is undoing and correcting mistakes that were made at planting time, whether it was earlier in the year or several years ago. We have planting specifications, but I think we're long overdue for "unplanting specs."
There are four areas where more follow-up care is needed: unstaking and untying, unwrapping, unmulching and unbinding.
While you're out "unplanting," don't limit yourself to trees and shrubs in your own yard. Look around -- there are plenty of trees and shrubs at your local schools, shopping malls, public parks and a variety of other locations where even the "professionals" didn't plant correctly or haven't provided adequate "unplanting" maintenance. You may get a few funny looks from people as they pass by, but you can rescue these plants from future problems and perhaps teach a few needed lessons about tree and shrub planting and care at the same time.
Unstake and Untie
A tree needs staking at planting time only if it is unable to stand upright without one, or if it needs protection from wind or people. Assuming the tree needed staking (many don't), a year should be plenty of time. If its roots can't hold it up after that period, there's another problem involved, such as poor roots or soil conditions, that staking won't solve.
Unstaked, trees will develop trunk girth faster, and will also have the strength to keep their posture when hit by wind. Even when staked, trees should never be held rigidly in place.
Untie trees so that the material used to connect the stake to the tree doesn't "girdle" or damage the bark. Girdling restricts water and food movement in a tree and leads to a decline in growth. It might even create a weak spot above the girdle that could break off sometime later.
While you're untying, remove any labels or tags that are still attached. Plants are good at "eating" such items, again causing girdling or weak areas.
Unwrap
Remove any kind of trunk-protecting wrapping that was installed at planting time. Just as with unnecessary staking, there is unnecessary wrapping. In a few specific situations -- trunk protection at digging or shipping time or heat protection if trees are planted into paved areas during the spring or summer -- a wrap for less than a year may help. In most cases, however, wraps don't encourage trees to become established and may actually cause problems.
Bark rotting, enlargement of trunk breathing pores or "lenticels," insect and disease problems and girdling from the wrapping's method of attachment are just a few such problems revealed by my research.
If a tree's trunk has been protected with a metal, plastic or other type of guard to prevent damage caused by machinery, animal feeding or vandalism, be sure it is loose. Otherwise, once again, tree-damaging girdling may occur at the guard site.
Unmulch
My third "unplanting" recommendation is to unmulch. Don't remove all of the mulch, but if you or someone else has gotten overzealous, meaning there is a layer of mulch more than four inches thick against the trunk of any tree or shrub, pull some of it away.
A three- to four-inch mulch layer is usually fine, but mulch against the trunk encourages bark decay or disease or insect problems. Excessive mulch can also create a welcoming habitat for animals such as voles that might feed on the base of your plants.
While you're pulling the mulch at the base of your plants back, check to be sure that your trees and shrubs weren't planted too deeply. The trunk flare or root-stem transition area should be at the soil surface. If the tree is too deeply set and has been in place for just a short time -- three to six months -- dig it up and plant it less deeply. If that's not possible, remove soil from around the trunk base, gradually tapering back to grade.
Unbind
Be especially sure that any root packaging or balling materials were removed at planting time. These include natural jute or synthetic burlaps, natural hemp or synthetic ropes, the tops of wire baskets, plastic sleeves, even plastic pots. It's amazing how many of these materials are left intact at transplant time, and how quickly they can limit root growth and plant establishment or cause stem girdling. Even the tops of "plantable" peat-paper-fiber pots should be broken away. Their slow rate of biodegradation often limits root development, and the fibers wick moisture away from the roots.
Dr. Bonnie Lee Appleton is a professor of horticulture at Virginia Tech University in Blacksburg.
Photography by Suzanne DeJohn/National Gardening Association
Fertilizing a Tree
National Gardening Association Editors
Most landscape trees growing in their natural environments rarely need fertilizer. However, trees growing in infertile soil along roadsides, in urban areas, and around new homes may need extra nutrients to keep growing strong. Apply in early spring or autumn when roots are actively growing.
Tools and Materials
• Granular fertilizer
• Tape measure
• Calculator (optional)
• Scale
• Garden hose
• Shovel to check moisture depth
Determine need for fertilizer. Compare trees to others of the same kind: look at leaf size and color, and the length of new twig growth. Small, pale leaves and stunted growth may signal fertilizer need, but first rule out disease, insects, physical damage, and environmental stress such as flooding or drought. To determine which supplemental nutrients your tree needs, send a soil sample to a testing lab. Find a lab near you by checking in your telephone directory, or by calling your local cooperative extension office.
Choose a fertilizer. Granular fertilizers are the easiest to apply. Choose one especially formulated for the type of tree, such as fruit or evergreen, or apply an all-purpose formula such as 10-10-10.
Calculate the size of the root zone. Tree roots grow at least twice as far from the trunk as the branches do. To calculate the root radius, measure in feet the distance from the trunk to the end of the longest branch. To calculate the size of the root zone in square feet, multiply (root radius) x (root radius) x 3.14.
Determine the required amount of fertilizer. You can safely apply up to 1 pound of nitrogen per 1,000 square feet per year. A 20-pound bag of 10-10-10 fertilizer, enough to cover 2,000 square feet, contains 10 percent or 2 pounds each of nitrogen, phosphorus, and potassium. Multiply your tree's root zone by the application rate per square foot to find the total number of pounds to apply.
Apply fertilizer. Measure out the amount of fertilizer you need. Mark the outside boundary of the root zone with a garden hose or a circle of flour or lime. Also mark a circle 3 to 4 feet from the trunk. Evenly spread the fertilizer between the two circles, avoiding application close to the trunk. If the tree is in a lawn, apply when grass is dry. Water to moisten the soil and distribute the fertilizer to a 12- to 18-inch depth.
Tips
Around trees and shrubs, avoid using "weed-and-feed" lawn fertilizers containing herbicides. Sensitive species may suffer from repeated exposure to these chemicals.
Some testing labs analyze leaves to accurately determine a plant's nutrition needs. For more information, contact your state's cooperative extension agent or a tree service.
Tree Care
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