If your sixth sense suggests that your so-called winter vacation away from the garden has come to an abrupt end, you're right. Fruit and shade trees have been pruned, but now the emphasis is shifting to the growing season. This weekend or next week, you'll want to fertilize your trees so they perform well over the next nine months of the growing season.
If you think back over recent years, you'll probably agree that you have been shortchanging your trees. In your landscape work, nothing has been too good for the shrubs, flower bed, lawn and such. Fine, but have you done the same thing for your trees?
For starters, picture a tree victimized by insects and disease, to the point that a tree company will be spending a full day "chain sawing" the tree piece by piece until only a stump marks the spot of the once majestic specimen. If you haven't priced tree removal lately, such costs usually begin around $1,500 and spiral upward. Removing a 60-foot oak could well cost you $4,000.
Smart gardeners know that fertilizer is much cheaper than tree removal, no matter how big the tree may be. Not only does annual fertilization trigger good performance, but a healthy tree is also the best deterrent against problems that invariably develop with neglected trees, for example, disease and insects. If you don't want tree problems later on, feeding them religiously year-by-year is your best insurance.
In a year when trees drop their leaves before Halloween, fertilize immediately after; however, if falling isn't complete by Halloween, delay tree fertilization until the first days of March.
Use the proper fertilizer. Trees that produce leaves or needles (including birch, maple, oak, sycamore, willow and evergreens such as cedar, fir, hemlock, juniper, pine and spruce) should get 10-6-4 inorganic. Trees that produce flowers (including dogwood, magnolia, tulip poplar, crab apple, and all fruiting and flowering fruit trees) should get 5-10-5 inorganic. Use the proper amount for each tree. Take a note pad to the garden, plus a ruler. Measure the diameter of the trunk at the soil line and multiply by two. A pine tree with a trunk diameter of eight inches should receive 16 pounds of 10-6-4 inorganic. A dogwood with a four-inch trunk should get eight pounds of 5-10-5 inorganic. There are some exceptions to the rule, but we'll specify them in a moment.
Fertilize in the proper place. Go to the tips of the outer branches of the tree; this is known as the "dripline." Below the dripline will be found the hairy feeding roots of the tree, so this is precisely where the fertilizer should be applied.
Plan to use a 10-inch-wide swath as your fertilizer strip. Simply go to the dripline, then six inches beyond the dripline. Using a bucket filled with limestone, walk around the tree just beyond the dripline and put down a line of lime to surround the tree. Now, go 10 inches inside this new line (toward the tree trunk) and lay down a second line of lime. You'll apply the proper amount of fertilizer, all of it, inside this 10-inch strip.
Use whichever feeding method is best for you:
Scatter the fertilizer inside this strip, encircling the tree as you do. Find the soaker hose you stored indoors last Thanksgiving, open the valve to exterior water lines, then let a lazy flow of water wash the water-soluble fertilizer into the subsoil. So much the better if it rains after the application.
Using a special twist drill inserted into your electric drill, drill holes into the soil every 24 inches along the periphery of the outer border of lime surrounding the tree. These drills vary in diameter from 1 to 2 1/2 inches, making it easy for you to apply fertilizer within easy access of the feeding roots; check the garden shop for these special drills on shafts of 16 to 24 inches. Insert the drill into the soil at a 10- to 15-degree angle in the direction of the trunk, thereby assuring food to the greatest number of roots. Make the holes 16 inches deep, then fill them with the proper fertilizer to within three inches of the top and backfill with soil. If needed, drill a second series of holes six inches closer to the trunk, filling them with fertilizer until the prescribed amount has been applied. If no rain follows, soak the fertilizer swath afterward.
Remember that a two-pound empty coffee can holds five pounds of fertilizer. This way, you should be able to apply the prescribed fertilizer for every tree.
If mulch covers the soil, temporarily rake it away from the dripline so fertilizer can be applied, then return the mulch.
Some trees respond negatively to nitrogen. Usually, excessive nitrogen in cells triggers a disease that, if not controlled, will eventually kill the tree in question. The disease, "fireblight," is manifest in mid- to late-June when leaves gradually turn color, ultimately black, then hang limp from limbs. Unless removed, the black foliage could well stay on the tree through the summer. Trees that are vulnerable include apple, flowering and fruiting almond, flowering and fruiting apricot, flowering and fruiting cherry, crab apple, hawthorn, mountain ash, flowering and fruiting pear, and flowering and fruiting plum and quince. To reduce chances of fireblight, use only one pound of 5-10-5 for every inch of trunk diameter at groundline.
If you remember seeing black leaves on any of these trees last summer, do not prune those limbs. The only way of knowing the progress of the disease is to wait until June when the black symptoms will again show up; by early July, you should prune beyond the last blackened leaf, thereby removing the disease and saving the tree at the same time.
Incidentally, some shrubs (blackberry, chokecherry, cotoneaster, pyracantha, raspberry, strawberry and spirea) are also attacked by fireblight, so go easy on nitrogen-containing fertilizers in late March and early April to avoid the problem.
Other priorities for this last weekend of February:
If you check your resurrected fuchsia, you should find the start of leaf buds on the lowest branches. Prune all stems to within a quarter-inch of these shoots because fuchsia will start flowering in late June only on wood grown from here on. Immerse the plant -- pot and all -- in a container of warm water to wash the old soil from the roots. Use a new plastic pot at least two inches wider than the old one. Fill half-way with your standard 1-1-1 soil mixture (equal amounts of milled sphagnum peat moss, perlite and vermiculite) with a teaspoon of ground limestone mixed in. Pot the fuchsia, flood the soil with warm water, then top off with more soil as needed. From here, keep the plant in bright indirect light, a warm room and fertilize with Peters' 15-30-15 to keep the soil lightly moist; never let the soil go dry. Finger-pinch the side shoots every other week to grow a bushy plant, halting the pruning around Mother's Day. Move the fuchsia outdoors in early June in full morning sun, shaded in the afternoon, and the delicate flowers will unfold the last week of June.
Check the tuberous begonias you've been keeping in dark closets for the first flower buds. They should then be potted (standard 1-1-1, with lime) and moved into bright indirect light to resume growth. Feed every three weeks with Peters' 15-30-15 for late May blossoms.
Stock up on 1-1-1, pulverized limestone, more plastic pots and water-soluble fertilizer to resurrect your indoor plants next week. You'll repot a handful, improve the soil of most, and make immediate applications of fertilizer to get surviving indoor plants growing vigorously again. Details will follow in next week's column.
Jack Eden hosts "Over the Garden Fence" Sundays from 10 a.m. to 1 p.m. on WTOP Radio (1500 AM).