Got roses? It's time for a tune-up.

Many roses are finishing a wave of bloom this month. Do nothing, and they'll continue to push out a reasonable number of new flowers. But tackle a few minor chores, and you'll dramatically improve their blooming.

Deadhead & Prune

Nobody likes looking at dead flowers, and many roses hold their blooms long after they've worn out their welcome. Aside from aesthetics, it's wise to cut off dead flowers on a regular basis so that the bush doesn't shift into producing rose hips - those end-of-season, round fruits that turn bronzy-purple or red and mark the end of flowering for the year.

When you dead-head, cut off the stem just above the joint where a side branch bearing at least five leaves is angling away from the center of the bush. You may notice a nub of growth has already started there: That growth will follow the same direction as the side branch.

By always snipping just above these outward-facing branches, you'll encourage the bush to take on an open, “V'' shape. This is important because the more open the bush is, and the more sunlight that reaches its center crown, the better your rose will grow and flower.

Also look for any branches that have sprouted below the graft - the knobby union at the bottom of the stem where the rose's roots are attached to the above-ground, flowering bush. This sucker growth tends to grow straight, fast, be covered in thorns and produce clusters of small, purple-red flowers bearing only a smattering of petals. The suckers also sap energy from the blooming part of your plant.

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During the first half of rose season, dead-heading at least once a week, above five-leaved branches, is generally all that's necessary. As for the five-leaf rule: A branch typically needs that many leaves in order to produce a new, vigorous, bud-bearing branch above it.

But after the July bloom, you can get a little more aggressive. This time around, cut back your bushes by one-third to a half. You'll force out new growth for bigger fall blooms and another nice cycle just before Christmas. On modern roses, it usually takes about 40 days from the time you cut until the next round of blooms.

Water & Mulch

Last month's record-breaking heat was tough on all plants. It's anyone's guess as to how hot July and August will be.

If we do have more heat, you may need to water your roses every day. Water early in the morning, so the leaves start out the day fully hydrated.

Some serious rose growers take an interesting approach to watering. Once a week, they deep-soak each bush with several gallons of water, to supply the tap roots that penetrate deep into the soil. Then they sprinkle the bed once or twice a week to keep the top soil evenly moist, which satisfies the feeder roots that travel just below the surface.

To apply the water, run a ring of soaker hose around each rose. Or use drip tubing and then punch in several emitters, shrubblers, spinners or mini-sprinklers so that you can water evenly all the way around each bush.

Also freshen up your mulch. Make sure it's at least

2 inches thick. Mulch will conserve water, protect the shallow roots from swings in temperature and help hold down weeds. You can use packaged bark, compost, grass clippings or even aged horse manure and pine shavings.

Keep the mulch from mounding over the crown. While the advice at bare-root planting time in January is to mound up mulch over the barren crown to protect it from cold and dehydration, this time of year you should leave the crown open so that the all-important sunlight and air reaches it.

If you leave the crown clogged with mulch now, the air can become stagnant, and fungal diseases and spider mites are more likely to strike.

Fertilize

There are two schools of thought on whether to fertilize your roses this time of year. Some folks say that if you feed them heavily enough in spring and have heavy clay soil, which tends to retain nutrients, you can get through summer without applying more.

But most folks advise providing a mid-summer boost. And if you have sandy soil, where nutrients leach out as fast as you can blink, this is surely a requirement.

Apply the fertilizer after you've cut back your plants by a third or a half. Use a liquid, which will deliver the nutrients fast. Fish emulsion provides a long-popular, mid-summer blast. Be sure to dilute it first, then pour it around the base of each plant. Spray it on the leaves, and you'll be greeted by a stinky scent for weeks.

A newer option is compost tea. You can spray both the leaves and the ground beneath without dispensing an unpleasant odor. Compost tea is packed with beneficial microorganisms, and provides a biological - rather than a chemical - boost.

You might also spread a few handfuls of dry alfalfa around each bush, then water it in. Alfalfa contains a growth hormone that will help keep your rose foliage healthy. Rather than buying a full bale, you can buy a bag at a pet food store. It's often sold with rabbit food as a tasty additive to mix with long-stem grass hays. Your annuals, perennials and vegetables will benefit from alfalfa, too.

Pests and diseases that trouble roses

The strongest, most vigorous rose bushes are the most likely to resist disease.

So if you keep yours healthy by dead-heading regularly, pruning for good air circulation, watering faithfully, maintaining a thick layer of mulch and fertilizing at the appropriate times, your roses should be well positioned to deflect problems.

However, depending on which roses you grow and how the weather swings, your plants can still be susceptible.

On the Central Coast, powdery mildew is widespread. The fungal disease poses an interesting problem: it thrives in cool, humid weather, but takes off most readily on dry - not wet - leaves. One of the most effective methods to knock it back is to hose off your roses first thing in the morning.

Tiny spider mites can take hold during hot, dry weather. The eight-legged, spider-like creatures suck the juices from the undersides of the leaves, which then turn a stippled yellow. You can keep the mites in check by frequently squirting them with a hose. Spray early in the day, so the leaves have time to dry before nightfall.

Neem oil, contained in products like Rose Defense, is an all-purpose, natural tool that coats the leaves and helps deter fungal diseases and bugs. Neem breaks down quickly, so apply it as frequently as the product label suggests. But don't spray it in the middle of a heat wave - a fresh coat of oil can literally cook the leaves.

Seeds of Wisdom:

If you're tired of dead-heading your roses, look for landscape or ground cover types that are “self-cleaning.” These roses drop spent flowers on their own. You'll still have to rake up petals, but that's less time-consuming than regular dead-heading.

PESTS AND DISEASES ATHAT TROUBLE ROSES:

The strongest, most vigorous rose bushes are the most likely to resist disease.

So if you keep yours healthy by dead-heading regularly, pruning for good air circulation, watering faithfully, maintaining a thick layer of mulch and fertilizing at the appropriate times, your roses should be well positioned to deflect problems.

However, depending on which roses you grow and how the weather swings, your plants can still be susceptible.

On the Central Coast, powdery mildew is widespread. The fungal disease poses an interesting problem: it thrives in cool, humid weather, but takes off most readily on dry — not wet — leaves. One of the most effective methods to knock it back is to hose off your roses first thing in the morning.

Tiny spider mites can take hold during hot, dry weather. The eight-legged, spider-like creatures suck the juices from the undersides of the leaves, which then turn a stippled yellow. You can keep the mites in check by frequently squirting them with a hose. Spray early in the day, so the leaves have time to dry before nightfall.

Neem oil, contained in products like Rose Defense, is an all-purpose, natural tool that coats the leaves and helps deter fungal diseases and bugs. Neem breaks down quickly, so apply it as frequently as the product label suggests. But don't spray it in the middle of a heat wave — a fresh coat of oil can literally cook the leaves.

— Joan S. Bolton

Joan S. Bolton is a local freelance writer and garden

designer. Her In the Garden column appears biweekly. She can be contacted through her Web site: www.santabarbaragardens.com.

July 2, 2008