Rose Bush Care Tips

Rose bushes require proper care to flourish. A preventative fungus spray and a jar of soapy water can help trap summertime pests, while mulching conserves soil moisture and controls weeds.

Recurrent blooming in bush roses depends on cycles of vegetative growth and flower bud formation, which requires abundant nitrogen. Regular pruning and timely application of fertilizer are essential to rose health.

Pruning

The timing and methods of pruning vary by rose type, but the general aim is to remove dead or diseased canes (stems) and encourage healthy growth. Prune hard in late winter or early spring as growth resumes, typically by mid-February in warm regions and March in colder ones. When deciding where to cut, consider the shape you want the bush to take, as well as how many blooms it produces. Prune out crossed branches that rub against each other and remove stubby snags, which do not produce any new growth or flowers. Also shorten sideshoots on shrub-type groundcover roses to control their size, and trim back spreading ramblers to two or three buds.

In the Southwest, the bacterial diseases crown gall and cane blight kill many roses each year, but vigorously growing plants are less susceptible to these afflictions than weaker ones. Powdery mildew may also plague roses, especially if the weather is hot and dry and the foliage does not get a chance to dry out. Frequent spraying with a water hose in the morning or evening can reduce mildew growth.

To prevent fungus problems like black spot, prune roses after the first flowering and use a general purpose fungicide in late winter. Spraying the leaves with a dormant oil, such as Bonide’s Garden Rich Pruning Sealer, coats canes and buds with an antifungal agent that suffocates the spores of overwintering fungi and halts fungal development.

Watering

Roses require ample moisture to promote vigorous shoot and flower bud development, but watering must be done correctly. Overwatering starves roots of oxygen and promotes fungal diseases. Watering too often can also cause the leaves to wilt and drop off. It is important to check the soil depth of moisture and aeration before watering. Watering deeply is better than sprinkling since the soaked ground allows the water to be absorbed more easily.

Rose bushes need about two inches of water each week (four to five gallons) in temperate climates. More frequent watering may be necessary in sandy or very dry soils. Watering should be done in the early morning so the plant can dry quickly in the heat of the day.

If you grow disease-resistant varieties, fungicides are not needed to combat common problems like black spot and powdery mildew. However, it is still important to remove faded blooms and dead stems from the plant, as well as improve airflow and keep the soil moist and cool to prevent fungus growth.

Mulching helps control weeds and keeps the soil cooler and moister, which reduces the frequency of watering. A layer of 2 to 3 inches will insulate the shallow roots and help prevent fungus. Make sure the mulch is kept away from the stem of the rose bush to avoid rot.

Fertilizing

Roses are heavy feeders that need balanced fertilizer to ensure strong, healthy growth and maximum bloom production. Fertilize in the spring when buds break open, then at regular intervals during the summer and after each round of flowers. Reduce application amounts with each occurrence to prevent over-fertilizing that can lead to leggy growth and early frost damage in the fall.

Look for an organic all-purpose fertilizer with a balanced nitrogen-phosphorous-potassium (N-P-K) analysis, such as horn shavings, Oscorna(r) rose fertilizer or dried cattle manure, or a commercial fertilizer with a high concentration of phosphorous and potassium, such as Super Bloom or Heirloom Roses(r). Some hobby gardeners use coffee grounds or eggshells, which are both high in nutrients, to provide a natural, inexpensive source of fertilizer.

Mulching is another important element in caring for a rose bush. A layer of mulch helps retain soil moisture, minimizes weed competition and insulates the roots during cold temperatures. Organic materials like shredded bark, rotted compost, straw or well-rotted manure are excellent choices for mulching, as they enrich the soil as they decompose.

If you’re growing roses in large pots, repot them each year, replacing the top inch of potting mix with fresh, soil-based mixture such as John Innes No. 3. A light application of granular plant feed or a pelleted chicken manure is also beneficial.

Pest Control

Roses are susceptible to several pests, including aphids, which chew slender stems and buds, distorting leaves and stunting growth. They secrete a sticky liquid called honeydew, which attracts ants and promotes the growth of black sooty mold. Spray with a strong jet of water to hose off an infestation, or apply insecticidal soap or low-toxicity synthetic insecticides. Be sure to also control the natural predators that control aphids, such as birds and beetles.

Leafhoppers and nymphs use their piercing-sucking mouthparts to feed on rose foliage, causing stippling spots that may merge to form white blotches on the leaf surface. A severe infestation causes yellowing of leaves and stunted growth. Insecticidal soap or horticultural oil can reduce populations of these pests.

Slugs leave ragged-edged holes in the center and margins of rose leaves, particularly during wet growing seasons. Watch for a slimy coating on the leaves and flowers, or look for slugs themselves at night when they are most active. Encourage natural predators, such as slug-eating frogs and salamanders, to keep slugs in check, and cover ground with a thick layer of mulch to prevent rot and provide a barrier for the roots.

Sawfly larvae feed between the veins of leaves, and young ones resemble moth or butterfly caterpillars. A horticultural or neem oil spray or a weak solution of Bt (bacillus thuringiensis) is a good control. For a stronger application, try carbaryl (Sevin), pyrethrins or spinosad, such as in Eight(r) Liquid Concentrate, Pyrethrins and Captain Jack’s Deadbug Brew(r). Handpicking is possible when the infestation is light.