Rose Care in the Low Desert

Soil moisture should be maintained to a depth of 2–3 feet. The amount of water required de- pends on your soil’s characteristics, weather conditions, and the particular microclimate in which you live. Irrigate slowly to ensure water penetrates through the entire root zone. This is important not only to supply moisture to the root system, but also to leach—or carry—salts be- yond the root zone.

Roses require more frequent watering than most other landscape plants. During the cool winter months, water roses once a week or when needed. In spring and fall, loam soils are usually irrigated two to three times per week. During the summer heat you will probably need to water three or four times per week. You may have to water every day, depending on your soil and weather conditions. (Clay soil retains more moisture than sandy soil. Loam soil is between clay and sand).

Container roses need to be watered two or three times per week during cool weather and as much as once a day in warm temperatures. Watch them carefully in the summer for signs of stress, such as wilting or yellow leaves.

The principal reason for cultivation is to keep grasses and weeds from invading the rose beds. If your rose bed is not too large, you can pull weeds by hand. Or cut weeds by shallow scrap- ing of the soil so as not to disturb the rose’s feeder roots developing and functioning near the surface. Shallower feeder roots are especially abundant if a mulch has been used. Avoid spad- ing the bed as it will cut large numbers of feeder roots.

Mulching materials such as compost, forest mulch, straw, or wood chips should be applied throughout the year. Layer 3–4 inches around each bush. Mulch helps to reduce weeds, retains soil moisture, and keeps roots cool. It also builds a healthy soil structure as it decomposes over time.

Roses are heavy “feeders” that need to be supplied with nitrogen and phosphorous. It is better to apply small amounts of a slow-release fertilizer every six weeks during the growing season, rather than a heavy application once a year. The first application of slow-release fertil- izer should be applied after the roses have been pruned in January or February and repeated every six weeks until June. For Old Garden Roses that aren’t pruned until after blooming, start fertilizing in January or February anyway to promote flowers. This is usually sufficient for most roses in a home landscape situation.

However, gardeners who compete in rose shows often supplement the above regimen with a liquid fertilizer every week or two during the same months. Liquid rose fertilizers, which are readily available to the plant, can be applied to the soil or sprayed directly on the foliage. A note of caution: foliar feedings are practiced only during the relatively cooler weather of March– April and late September–October when the roses are in peak bloom periods. Apply early in the day before the sun heats up. Test a few leaves before spraying the entire bush. Using spray fertilizers during the hot summer will likely burn the foliage and is not recommended.

Some rosarians recommend that roses be given a break during the hot summer months with no fertilizer applications. Then start the slow-re- lease fertilizer again in September, with the last application around mid-October. Other rosarians prefer to continue using slow-release fertilizer at half-strength throughout the summer. Determine what works best for your roses in your condi- tions.

Miniature roses usually require less fertilizer than other types. Container roses require less total fertilizer than those grown in the ground; however, they need more frequent applications as their roots can’t seek further nutrients beyond the confines of their pot. Always water thor- oughly before and after fertilizing to help pre- vent burn. Follow directions on the container when using any fertilizer.

• Deep water to a depth of 2 feet throughout the growing season.
• Hose off roses regularly with water. Spray in the early morning before the sun gets hot to decrease chances of leaf burn. Spray the underside of the leaf. This will keep the roses clean, increase the surrounding humidity, and will help to control insects before they can cause any damage.
• Use a forceful water spray to eliminate aphids and spider mites.
• Roses slow down during our hot months and produce smaller and fewer blooms. Remove spent blooms by cutting back to the first five-leaflet set. Leave as much foliage as possible, which will help to shade the bush.
• Shade the trunks of tree roses during our hot summers to prevent sunburn. Painting the trunk with white tree paint or covering the trunk with cardboard or shade cloth will also help
• Watch for sucker growth on grafted roses. These are canes that come from below the bud union. They appear different from the other canes. Cut them off below the bud union.
• Seal all pruning cuts with a good wood glue to prevent cane borers from entering. The borer larva eats the stem center and the infested cane grows poorly or dies. Cut back the injured cane an inch at a time until you find healthy wood. • Learn to recognize Lady Beetles, Lace Wings and other beneficial insects in all stages of their lives (egg, pupa, adult).
• Check roses on a regular basis to identify potential problems.

A special thanks to MaryLou Coffman for her assistance on this publication who is a master gardener and consulting rosarian.