If you want to keep the trees in your yard healthy for years to come, spend time this Halloween weekend putting your dogwoods, flowering cherries and stately Japanese maples in order for 1988.

It doesn't matter what your trees may be, their age or the extent of tender, loving care showered on them this summer. You should be fertilizing them now, then deep-soaking the roots for the next six weeks.

When you are finished in mid-December, you can bet that your trees will be standout performers next year.

Fertilizing comes first. Fruiting, ornamental and shade trees should be fertilized now, but evergreens (fir, pine, spruce) won't be fed until early March.

Your choice of fertilizer depends on the tree's growing habits:

For trees that produce leaves but no flowers, use 10-6-4 inorganic fertilizer.

In this category are ash, birch, elm, maple, oak and willow. Measure the diameter of the trunk at soil line, then apply two pounds of fertilizer for every inch of trunk diameter. For example, a maple with a 6-inch trunk will receive 12 pounds of 10-6-4 inorganic this weekend.

For trees that produce flowers, use 5-10-5 inorganic fertilizer.

In this category are almond, apple, apricot, catalpa, cherry (Kwansan, Yoshino, etc.), Chinese chestnut, crabapple, dogwood, hawthorn, horse-chestnut, linden, locust, magnolia, mimosa, mountain-ash, nectarine, peach, pear (Bradford and fruiting varieties), plum (flowering and fruiting), quince, redbud, and tulip poplar.

Feeding rates for flowering trees will vary because too much nitrogen to certain trees triggers fireblight disease in the spring, leading to the death of the tree unless pruning removes the disease.

Here are recommended feeding rates for flowering trees:

Use one pound of 5-10-5 for every inch of trunk diameter at soil line for fireblight susceptible trees, namely apple, almond, apricot, cherry, crabapple, hawthorn, mountain-ash, pear, plum and quince.

A flowering cherry with a five-inch trunk should get five pounds of 5-10-5.

Use two pounds of 5-10-5 for every inch of trunk diameter for other flowering trees, namely catalpa, Chinese chestnut, dogwood, horse-chestnut, linden, locust, magnolia, mimosa, nectarine, peach, redbud and tulip poplar.

A dogwood with a four-inch trunk should receive eight pounds of 5-10-5.

The best guide for measuring fertilizer is an empty coffee can. A one-pound can holds 2 1/2 pounds of fertilizer, a two-pound can holds five pounds.

Fertilizer is applied within access of the feeding roots at the tree dripline. Imagine a strip 10 inches wide that encircles the tree.

The outer edge of this strip is at a point about six inches beyond the dripline of the tree. Apply the fertilizer inside this strip.

Some hints on applying fertilizer:

If you are applying a small amount of fertilizer, sprinkle it over the grass covering the dripline, then soak the grassy area immediately and often for the next few weeks.

If the soil at the dripline is mulched, it makes no difference whether small or large amounts of fertilizer are being applied. Apply fertilizer at the dripline over the mulch, then start soaking immediately.

If you are applying large amounts of fertilizer, and grass covers the dripline area, sprinkling fertilizer over the sod would result in an immediate fertilizer burn.

To avoid killing this grass, you should bore holes into the soil instead, then fill these holes (as many as possible) with plant food.

Most garden shops today carry soil drilling bits for feeding trees. Here, you're looking at a one-inch drill bit on a 16- to 20-inch shaft that fits into the chuck of your quarter-inch electric drill.

Standing some six inches beyond the dripline, insert the twist drill into the soil at a 15- to 20-degree angle in the direction of the trunk, then drill an inch-wide hole about 16 inches deep. Move 10-12 inches to the side and drill another hole, eventually encircling the dripline area.

A second circle of similar holes may be bored eight inches inside the outer ring if the tree calls for an extraordinary amount of fertilizer. Fill each hole with 5-10-5 to within four inches of the top, then backfill with pure sand or soil, and start soaking.

Incidentally, tree spikes are not a viable alternative to this fertilizing scenario.

Trees will absorb fertilizer for the next six weeks, storing food in the trunk until sap begins to rise in the tree, at which time nutrients will be dispatched to leaf and flower shoots.

Thanks to your timely feeding now, the tree won't require any fertilization until Halloween of next year.

Watering is essential, not only to wash fertilizer to feeding roots, but also to fill water reservoirs so trees and shrubs survive the winter.

You can't trust November rains to do the job; you've got to be soaking now and for the next six weeks to guarantee their winter survival. Dieback of shrubs and trees occurs when plants run out of water during the winter; the soil being frozen, roots cannot obtain water.

How should you water? Religiously.

Trees fed now should be soaked twice weekly, evergreens and shrubs once-a-week at the dripline.

This is no time to think of storing the hose and sprinklers; if you do, expect varying degrees of dieback in the landscape next spring.

Oscillating and impulse sprinklers should be left in place for an hour when you water, directing the water to tree driplines in the coverage area.

A soaker hose placed at the dripline, with the faucet one-third open, will saturate the soil without any runoff. Soak at least once a week, and don't neglect spring flowering shrubs (azalea, rhododendron, forsythia, etc.), plants started from cuttings this year, transplants and plants set into the garden anytime this year. Spring bulbs merit occasional soaking, too.

Other priorities for the weekend:

Apply potassium sulfate (0-0-50) this weekend after cutting the lawn. By volume, you should apply four pounds per 1,000 square feet, working out to two pounds of actual potash over the area.

With the rotary Spyker or Cyclone, use setting number 4; with the Scott drop spreader, use setting 4 3/4. Water the lawn afterward.

Stock up on mulch (shredded bark, bark chips) which you will need after New Year's Day to mulch shrubs, mums, Daisy Miller and September transplants.

Lay in a supply of quality bird seed for your aviary friends and feed them generously. Winter birds linger in the spring garden, providing protection early next April when they feed on the resurfacing grubs.

Hibiscus flowering is at an end, so pinch the last withered blossoms and force the plant to go dormant.

Put the plant in bright, indirect light, but the room temperature must stay between 54 and 58 degrees at all times. Run a thermometer test to be in the temperature range.

Let the soil go dry for one day, then apply warm water (just like you're caring for African violets, cyclamen, Norfolk Island pine). Water in the sink and drain for 15 minutes before returning the plant to the saucer or tray.

Temperatures over 58 will trigger yellowing of leaves, followed by leafdrop; temperatures below 54 cause root rot.

No fertilizer of any kind should be used until late February when you resurrect the hibiscus.

Jack Eden hosts "Over the Garden Fence" from 10 a.m. to 1 p.m. Sundays on WTOP Radio (1500 AM).