Easy tips for beautiful roses
Worldwide, there are more than 200 species and thousands of cultivated rose varieties. Roses are among the hardiest of all plants. In the desert, they do best with afternoon shade and at least 6 hours of full sunlight each day to produce abundantly and reach their peak quality.
ROSE IDENTIFICATION BY CLASS:
Roses are most often described by type or class. Descriptive terms you are most likely to encounter are as follows:
Hybrid Tea: The most popular class of roses. They have large, well-formed, single blooms on long cutting stems. Height ranges from 4 to 6 feet.
Grandiflora: A newer class of roses. Usually taller than Hybrid Tea (8 to 10 feet is not uncommon) they have long cutting stems with clusters or sprays of large blooms.
Floribunda: Descended from Hybrid Teas and Polyanthas. Medium to small blooms are formed in clusters or sprays on shorter stems. Short, bushy plants usually range from 3 to 4 feet tall.
Polyantha: Short, glossy-leafed bushes covered with clusters of double flowers in pink, white or salmon. Great for borders. Size ranges from 1½ to 3 feet tall. Also occurs in climbing varieties.
Shrub: Includes the English (David F. Austin) roses. Characterized by dense growth, neat plant habit and continuous bloom. Reaches 2 to 4 feet in height.
Miniature: Overall plant size varies. Some have tiny leaves and 1-inch blooms while others have larger leaves and 3-inch blooms. Excellent in pots; beautiful in tree rose form.
Patented Rose: Newer variety developed by a rose breeder. Protected from duplication and sale by others with a patent. Patents for plants, like many other items, are currently good for 17 years.
Non-Patent Rose: Older varieties no longer covered by plant patents. These tried-and-true roses have been grown successfully for a long time.
For best results dig a hole 2 feet deep and 2 feet square. The planting area should be out of grass and free of tree and shrub roots. Check drainage by filling the hole with water. If the water remains in the hole for more than 4 hours, then correct the drainage problem by digging deeper until the water drains readily. Remove or fracture restrictive caliche layers to allow drainage.
Our soils have no naturally occurring organic matter. Improve the soil by blending equal amounts of a soil amendment like Paydirt™ Planting Mix with the native soil. Add a cup of Dr. Q’s® Gold Dust Starter Fertilizer and a cup of Soil Sulfur.
SELECTING DORMANT ROSES
Roses can be purchased as active plants; in rigid plastic containers or dormant; in plantable pots or bare root (plants without actual soil around the roots). In the desert southwest, gardeners can successfully plant container-grown roses anytime except during the intense heat of summer. Bare root and Dormant Pot roses should be purchased and planted from December through February. Planting these roses after this time has produced limited success since the plants have little time to establish before the hot summer arrives.
Select grade No. 1 roses for best results. These roses will have three or more canes that are 12 to 18 inches long. On bare root roses, the buds and canes should still be dormant.
PLANTING DORMANT POT AND BARE ROOT ROSES
follow package instructions.
Read Star Note # 520A Planting a Bare-Root Rose and # 520B Planting Dormant Pot Roses for complete instructions on successful planting. For best results, prepare the soil in advance and plant immediately after purchase. The Dormant Pot Roses can be planted directly in the degradable pot they come in. To expedite root growth, you may cut vertical slits in this pot, or remove it. Hot spring winds dry out newly emerging canes. To prevent desiccation and stimulate new growth, cut the bottom out of a 5-gallon plastic container and place the container over the rose. Fill it with coarse mulch or small bark. Keep moist until shoots emerge then remove container and let irrigation erode the mulch away.
It’s best to not plant wax-coated plants in the desert Southwest. While wax does protect buds and canes from desiccating (drying out), warm weather and intense sunlight can cause heat build up under the wax and kill the plant. Waxed cane tips are acceptable since they won’t dry out as quickly and can be trimmed when the plant starts to grow. If the wax extends beyond the tip of the cane, often it can be removed by flaking it off, or you can run the waxed portion of the cane under warm water (place under running tap) and gently scrub with an old toothbrush. After purchasing bare root roses and before planting, keep them in a cool, dark, moist place.
PLANTING AN ACTIVE CONTAINER ROSE:
Remove the plant from its container and examine the roots. If they are tangled, make vertical cuts on each side of the root ball with a sharp knife. Trim broken or crushed root ends. Place enough prepared soil mixture in the hole so the crown (knobby area where roots and top are joined together) will remain above ground after planting. Place root ball in the hole and add remaining soil. Add water to settle the soil. Cover all exposed roots with at least two inches of soil. Pack the soil lightly with hands or feet. Build a 2-foot diameter irrigation basin around the rose then water again using a root stimulator solution like Dr. Q’s® Plant Tonic.
After planting, prune canes to approximately 8 to 12 inches. Make the final cut above an outside facing bud so new growth will develop outward rather than into the center of the plant. Remove any weak canes by cutting back to the crown. Treat cuts with a commercial pruning seal, clear fingernail polish, wood glue or light-colored latex (water base) paint. This will protect the canes from drying out and stop invasion of cane borers and other insect pests.
CARE AFTER PLANTING:
Mulch the irrigation basin to conserve moisture, lower the soil temperature and control weeds. Use fully composted mulch to assure that plants are not damaged by lack of nitrogen.
FERTILIZING ESTABLISHED ROSES:
Nitrogen, phosphorus and potassium are the major or macro nutrients needed to produce quality roses. Trace elements such as iron, magnesium, manganese, zinc and sulfur are also essential. Use a packaged rose fertilizer like Dr. Q’s® Rose & Flower Food or an all-purpose balanced fertilizer to supply these nutrients. If using organic fertilizers like blood meal, cottonseed meal or fish emulsion, use trace element supplements like Ironworker® or Kerex® as well.
How often should you fertilize roses? This is the rose question most frequently asked by everyone! Some say every 2 weeks, others every 4 weeks, still more say every 6 weeks. The answer depends on the kind of fertilizer you are using – – foliar, water soluble or granular. Foliar sprays and water soluble drenches are absorbed much more rapidly and require more frequent application. For the home gardener, granular rose fertilizers like Dr. Q’s® Rose Food provide continuous, long-term feeding which insures controlled growth and heavy flower production. To assure a constant supply of blooms, apply the fertilizer every time the current crop of buds first begins to show color. Don’t wait until they have fully opened.
Spread fertilizer evenly over the soil surface starting 6 inches from the plant base and ending 12 inches beyond the bush drip line (the circle defined by foliage spread). Lightly scratch nutrients into the soil. Keep cultivation shallow to avoid injury to shallow feeder roots. Irrigate before and after fertilizing to prevent burning. When using any fertilizer, always read the label and follow directions.
Avoid using foliar fertilizers like Miracle-Gro® during hot weather. When using them always apply in the early morning to avoid leaf burn. These fertilizers provide quick results but do not replace soil fertilizing.
DO NOT FERTILIZE ROSES with any significant NITROGEN IN NOVEMBER, DECEMBER AND JANUARY.
Allow them to go dormant and store energy for the next spring. See StarNote 605, Fertilizer Mixture for Established Roses, for the formula to bring your roses out of winter sleep and into terrific spring production!
A 2-4 inch layer of bark mulch will cool the ground, prevent weed growth and enrich the soil as it slowly breaks down. Western Red Cedar Mulch contains cedar oil that repels insects as well. Do not use rocks as mulch around roses. It super heats the soil and often leads to over watered, soggy conditions as well.
Proper watering is always necessary to produce quality roses in our climate. Light, frequent irrigation causes shallow root growth leading to stress during the summer or windy days. Deep, infrequent watering is most efficient and effective. This practice allows the roots to “breathe” between irrigations, encourages roots to grow deeply, avoids root rot disease and flushes away harmful salts.
Determine when to irrigate by testing soil 2 inches below the bush canopy. An inexpensive moisture meter is an excellent tool for this task. Not only will it tell you if the moisture content is correct but also if water is being evenly applied and absorbed around the whole plant. Modern irrigation timers are great labor saving devices but using them incorrectly can cause serious over or under watering, plant stress and death. Stay in touch with your soil. There’s no substitute for observation and subsequent adjustment!
COMMON DISEASE PROBLEMS
Here are some of the most common problems you are most likely to encounter when growing roses:
Powdery Mildew is a fungus that is first noticed as a white, powdery coating on leaves, stems and buds. Leaves become curled or twisted, shoots look badly deformed and buds shrivel and fail to open. Ideal conditions for infection occur when warm days are followed by cool, damp nights. The fungus may infect older leaves. Often the upper leaf surface appears normal, but there is extensive fungal growth on the under surface. Reduce chance of infection by keeping the area around the bush free of debris. Prune out and destroy diseased canes and leaves. Avoid planting roses in excessively shady spots that dry out slowly. Prune thoroughly each winter to promote free air circulation. Water early in the morning, not at night. Avoid overhead sprinkling if at all possible. New growth is highly susceptible to mildew during hot, dry periods.
Prevent the disease by soaking dormant roses in winter with a Dormant Disease product. If mildew does appear, treat with a fungicide like Ortho® Rose Pride Disease Control®. Always follow label directions and keep pesticides out of the reach of children.
Black Spot and Rust are other fungal diseases which affect roses in most parts of the country. Our dry climate and low humidity usually provide effective control. Proper watering habits as mentioned previously should keep these fungi out of your rose garden. If they should show up, the fungicides mentioned above will provide excellent control.
Crown Galls are evidence of bacterial infection that occurs on roots, crowns and stems. They begin in wounds caused by weed whackers, pruning, or grafting. They show up most often as ugly, misshapen growths on canes, stems or leaves. If localized, prune out and destroy affected parts. Treat pruning tools with a 5 percent solution of household bleach after each cut. Treat the pruned plant areas as well and protect with a pruning seal. Remove and destroy seriously infected plants.
Iron Deficiency (Chlorosis) is a major problem for roses in desert climates. Symptoms show up on new growth as yellowed leaves with bright green veins. Leaves turn nearly white, then brown, then fall as the condition worsens. Plant growth slows and death results if the problem is not corrected.
Highly alkaline soil, over watering, poor drainage and lack of available iron induce iron deficiency. To correct, reduce watering frequency, improve drainage if possible, and mulch regularly. Apply a soil conditioner like Con-GroTM to reduce soil pH. Add iron supplements like KeRex® or Ironworker®. Foliar application of iron may cause leaf burn if temperature is above 85 degrees. Spray both sides of the leaves with Liquinox Iron & Zinc; add a few drops of liquid soap to the solution for more effective coverage. Gardener’s Tip: Iron supplements will not be effective if your problem is due to over watering. Correct your watering habits first, then apply the supplement!
Insects and pests like our climate as much as we do! While many of them don’t bother roses, there are a few that we need to be concerned about.
Aphids are soft bodied, green, yellow, brown or red insects that suck plant juices. They are our most common rose pest. They seldom cause fatal damage but can stunt bushes and ruin appearance of roses. Aphids show up most often in clusters on new shoots and buds. They leave behind a sticky, shiny substance called honeydew that attracts ants. Spray plants with strong jets of water, use insecticidal soaps or choose from several commercial insecticides. Aphids are among the favorite foods of Lady Bugs, Lacewings and the strangely erratic Hoverflies. These biological controls are not compatible with insecticides, so choose your control method carefully.
Cane Borers are small fly larvae that enter the tips of recently pruned rose canes and eat the soft, center tissue. Once inside, the only way to get rid of them is to cut out the infected canes. Prune below any discolored areas then seal the cut with pruning seal, water-base paint, wood glue or clear fingernail polish. Prevent these pests by sealing pruning cuts when planting or preparing roses for winter dormancy.
Leaf Cutter Bees cut half moon shaped sections of leaf tissue from roses and other tender-leafed plants to make their nests. They stop nesting on their own after a short period of time. The damage is primarily cosmetic. The bees are great pollinators and they do not sting! An effective control to repel the bees without harm is garlic oil spray.
Spider Mites are not true insects but are pesky critters nonetheless. They are very small, nearly microscopic bugs that suck plant juices from the leaves of roses and other plants. They will appear on the undersides of leaves as small, dark specks. Leaves may have a mottled, yellowish look and be slightly curled or droopy. They may also be covered with spidery webbing in extreme cases. Mites like a hot, dry, dusty environment and may be controlled by washing leaves with a strong stream of water, or by using a miticide like Malathion, Bug-B-Gon or Insect, Mite and Disease Control.
Thrips are extremely small, very active, slender yellow- brown insects that hide in the base of rose blooms and leaves. They freckle petals and deform flowers and new growth. Damage is far more noticeable on lighter colored varieties. Spray developing buds and new growth with Malathion or pyrethroid based insecticides to control.
MONTHLY CARE OF ROSES
Use the following calendar to plan and maintain your rose garden.
January: Plant bare root and plantable pot roses through mid-February. Prune plants before they begin to leaf out. Strip all leaves from rose canes prior to pruning to force the bush into dormancy. Climbing roses should have no major pruning the first 2 years after planting. Remove spindly, non-supportive growth and dead wood only. Use a stiff brush to remove loose bark from the crown. Remove debris from the area around the plant and then spray plants thoroughly with a mixture of Volck Oil and Dormant Spray, or use a product like Neem Oil to kill over wintering disease spores, insect pests and their eggs. Most Star Nursery locations offer rose care seminars this month. Check with your favorite location for the correct dates.
February: Plant container roses of all types. Give your established roses a wakeup call with the special Rose Potion listed in StarNote 605, Fertilizer Mixture for Established Roses, to stimulate new cane growth and improve bloom quality. Always water plants thoroughly before and after application.
March, April and May: Fertilize every 4-6 weeks with Dr. Q’s® Rose & Flower Food. Apply iron supplements as needed to control chlorosis. For exhibition quality blooms, foliar feed with a soluble fertilizer in late March and early April. For larger blooms, remove secondary buds on hybrid teas and grandifloras. For a more uniform bouquet or spray of flowers, remove the center bud on floribundas. If you don’t know what kind of rose it is, ask us! The largest rose display here occurs from April through May. For fresh roses, cut back to where the cane is about as thick as a pencil. Cut just above an outside-facing leaf. This keeps good bush structure and allows formation of sturdy support for new blooms.
June, July and August: Fertilize roses at 1/2 the normal rate. If roses get direct sun all afternoon, do not fertilize in July or August. Intense, prolonged heat has the same dormancy effect as severe winter cold. Give the roses a break; let them rest. A thick layer of surface mulch will cool soil and conserve moisture. Deep, infrequent water, perhaps twice a week, is sufficient. Remove faded roses after bloom but keep as much foliage as possible. Beginning in late August, give roses a “haircut.” Remove all weak, undesirable or damaged canes. Do not “skin” lateral canes from major ones, but leave a 1/4 inch stub. Seal pruning cuts as mentioned previously. Reduce top growth by about 1/4 to bring on fall growth. Fertilize and water thoroughly.
September: Return to the spring schedule for fertilizing. For the first feeding, add 1/2 cup of soil sulfur and bone meal per plant. For larger blooms, apply a foliar fertilizer every two weeks until buds show color. Spray to control insects or diseases.
October: With cooler weather and shorter days, extend the time between irrigations, but do not let the root zone dry out. Soil surface mulch will help with this. The primary fall bloom cycle for roses begins this month and continues through November. If desired, foliar fertilize until buds show color. Remove any suckers that rise below the graft or crown near the soil line. Keep spent blooms pruned off to stimulate repeat flowering.
November and December: Irrigate roses every two weeks as needed. Adjust schedule according to rainfall. Now is the time to prepare new rose beds. Evaluate your roses and discard those that did not perform to your expectations. Replace with newer, more prolific varieties. Plant dormant pot or bare root roses through mid February. Have your soil tested if all roses performed poorly.
For more information on growing roses in Southern Nevada, contact the South Valley Rose Society at 435-8923, the Clark County Cooperative Extension Office at 222-3130, or ask one of our friendly sales associates.
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