Maintenance is pretty much the garden dogma for the balance of the summer. Always, there are some exceptions, but few of us are busy with major landscape projects at the moment; everything is geared to keeping what you have.

Next weekend, folks with vegetable gardens will be busy planting the fall crops and, the first weekend of August, readers with second-rate lawns will embark on lawn renovation work. Meanwhile, it's back to the summer maintenance chores, so take your pick. Gypsy moths have been laying eggs for the past two weeks, so this is your signal to start trapping flying male moths with gypsy moth traps. Not every reader need worry about gypsy moths, only those in neighborhoods where moths attacked trees in the spring, or on the periphery of such communities.

Ideally, string the traps as high in the trees as possible because 95 percent of the females are found in the top third of the tree. Remember, males fly, females do not.

Females release a scent (called "Dispar") which attracts the male for mating. Scientists have duplicated the scent (they call it "Disparlure"), and this is what summons male moths to the gypsy moth traps.

Every female moth that doesn't mate means 800 fewer gypsy moths come spring of next year, so the traps are worth the investment. Leave them up until late September, then follow label instructions for disposal. Readers who refused to spray for mites back in early June probably haven't changed their minds, but their shrubs and young trees have. A quick check of evergreens and small trees will reveal the start of spider mite damage.

Unfortunately, the browning of needles and leaves is only the tip of the iceberg because, even if the mites were killed today, the dieback would continue for another four to six weeks. The reason: Mites have been living off the sugar normally flowing to needles and leaves; take away the sugar and these plant parts die.

On the other hand, if you've been spraying these past six weeks, know that the shrubs would not have survived were it not for your sprays. Continue alternating Cygon (4 teaspoons per gallon) or Orthene (l 1/2 ounces per gallon) every three weeks through mid-September, but spray only when the temp is below 80. This weekend and next week marks your final fertilization of spring-flowering and evergreen shrubs for the year, the likes of azalea, boxwood, camellia, cotoneaster, euonymus, forsythia, holly, laurel, lilac, ligustrum (privet), pieris japonica (andromeda), rhododendron, taxus (yew) and viburnum, plus juniper, fir, pine and spruce.

Use a water-soluble plant food (Miracid, RapidGro, MiracleGro, or Peters' 15-30-15, or 17-6-6- or 21-7-7), applying one gallon for small plants and two gallons for larger shrubs; apply at the dripline (tips of outer branches), then soak the area to wash the plant food to the roots. Apply no fertilizer after this. Potpourri anyone? With the rose petals dried from June, use them now for making potpourri.

For every four quarts of rose petals add a handful of dried petals of other fragrant flowers (gardenia, jasmine, etc.), then add a half-handful of herbs such as bay leaf, mint, marjoram or rosemary. Mix these together and dry them. In another bowl, mix one ounce of powdered cloves, an ounce of oil of bergamot, half-ounce of orrisroot, half-ounce of borax and a half-teaspoon of allspice with a pound of kitchen salt.

Put down a layer of your rose and flower petals into a crock, over which is strewn a layer of your fragrances and salt mix, followed by another petal layer and a layer of fragrances. After you have exhausted your materials or filled the crock, stir the contents thoroughly, cover the crock and let it stand for a month, after which you add the fragrant potpourri to individual plastic bags for storage. Potpourri will last a year. Drying flowers or wildflowers? Silica gel is as perfect as you will get, but the homemade drying compound works as well and is lots cheaper. Add 10 parts cornmeal to three parts borax, mix and use as your dried flower material. Aphids are carrying poisons of all kinds now, so you risk losing your bedding plants to terminal viral diseases if the aphids persist.

Simple kitchen flour dusted on wet bedding plants will stop aphids, otherwise rely on Sevin or Rotenone powder dusted on the plants. Hose down the garden momentarily, then dust the foliage. Repeat after it rains. Blueberry plants are within 10 to 14 days of harvesting, so deep soak the plants every five days from here on to correct water stress problems that would otherwise affect the fruits. Delphinium will flower again if they're not neglected. Pinch stalks below any withered flowers, then feed with three pounds of 5-10-5 for every 100 square feet of delphinium bed (an empty one-pound coffee can holds 2 1/2 pounds of fertilizer); soak the garden afterward.

Four weeks later, fertilize again at the same rate. Flowers will begin in late August and continue through September; spikes should be three to four feet tall.

Next year, pinch stems as the flowers wither in late June, fertilize then and 30 days later. This will advance the August flowering considerably. Petunias won't disappoint you if you follow this scenario. Wait until the flowers are withering (which varies for all hybrids), then pinch below the blossoms; leave foliage on the stems, however. Feed promptly with Peters' 20-20-20 water-soluble fertilizer (15-15-15 is fine as a substitute), repeating every four weeks up to about Sept. 10 to 15; use the soaker hose after each feeding.

Petunias will reflower three weeks later. Because the plants have no insect or disease problems, you should have problem-free petunias right up to the first killing fall frost. If you don't prune the plants after the flowers fade, you won't enjoy any repeat flowers the rest of the year.

Incidentally, a two or three-inch hardwood mulch is perfect for petunias. Want summer flowers on your gardenia? The trick is night air temperature. Daytime, give the gardenia as much sun as possible. Keep the soil lightly moist and fertilize every l0 days; growth should be exceptional.

If you want flowers, move the gardenia inside where the air temperature is between 60 and 62 degrees at night; again, the plant goes outdoors every morning, but back to the cool spot in the house every evening. With this scenario, the flower buds will be there in two-plus weeks, at which time you stop fertilizing while keeping the gardenia in the 65-70 degree temperature range at night. You might even want to keep the plant indoors for the flowering cycle to enjoy the fragrance.

Flowers will last for 10 to 14 days, after which you pinch the stem below the flower, resume feeding and return to the nighttime temperature range. The bottom line is that the plant will only set buds when the temperature at night hovers between 60 and 62 degrees. Peach tree in trouble? Aside from the peach tree borer season, which is in progress, you might have experienced an unexpected leafdrop on the tree last month; if so, recognize the presence of a disease on the tree and the necessity of stopping it.

Rake up fallen leaves on the ground, add to the trash can and tie a ribbon on the peach tree to remind you of the carryover problem into 1987. Next March or early April, the ribbon will remind you of the disease.

As the leaf buds start to unfold, you will spray once or twice with lime-sulfur, and that snaps the disease cycle. The disease is called peach leaf curl.

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