Regional Growing Guide: Upper South
Hot, hazy and humid describes much of the year in this region, where roses commence their first peak of bloom by Mother's Day, then continue budding out and blooming through December. While most of the rain comes during winter and early spring, fierce afternoon thunderstorms, nor-easters and even hurricanes may blow through during summer months. The soil may be acidic or sandy: amending with lime helps balance the pH, while compost provides nutrients and improves drainage. The best roses are heat tolerant and resist black spot: new roses often offer improved repeat blooming as well.
Select a season: Spring Early Summer Late Summer Fall Winter
Roses are a favorite in so many gardens. But let's face it, those gorgeous flowers are sometimes accompanied by various rose diseases and pests. Is there an alternative to regular pesticide applications to keep these beauties producing the blossoms we so covet? Definitley, but it takes starting with the right rose and just a little care throughout the season.
Resistant Varieties
The first practice of a good rose grower should be to grow disease-resistant roses. Chosing any of the our AARS winning roses is a perfect place to start. You can visit one of our accredited public rose gardens to see these roses in the garden environment and chose the one that will be perfect for your needs. This will start you on your way to selecting roses for your own garden.
Another way to find the right rose for your garden is to read the most recent literature and catalogs. Breeders are constantly working on developing resistant roses, and the varieties available are expanded every year. One tip: a rose with a particularly leathery, puckered leaf is usually more resistant to leaf problems than one with smooth leaves.
The most common rose diseases are black spot, rust, and powdery mildew. All are fungal diseases, spread by spores being washed or blown onto leaves and stems.
Learn to Recognize Diseases
Black spot starts as tiny black flecks that turn into larger circular black spots. Eventually the spots coalesce into large lesions and cause the leaf to yellow and fall off. The spots appear on leaves and stems, and spend the winter on fallen leaves and infected canes.
Powdery mildew appears first as very small blister-like areas on young leaves, causing them to pucker. As spores reproduce, the leaf and flower buds become covered with a gray-white powder.
Rust, as the name implies, appears as rust-colored spots on foliage.
Preventive Strategies
Research has shown that black spot spreads most readily when foliage is wet. Therefore, planting in full sun, pruning to keep the shrubs open to circulation, and watering only at ground level will help prevent infection.
Powdery mildew, however, is best prevented by wetting the leaves since it needs dry conditions to thrive. A strong water spray several times a week will help prevent infection. As a bonus, this also helps control pests such as aphids and spider mites.
Another preventive method for diseases is to remove all foliage on the plant and on the ground in late fall, and to prune the tips of the canes. Both pathogens overwinter in fallen tissue and in the leaf buds just below the flowers. Pruning and clean-up get rid of many overwintering spores. If the canes are badly infected, a rose can be pruned to 4 to 6 inches from the graft with no harm.
Head Over Heels Over Roses
Love tends to sneak up on you when you least expect it. How was I to know that a stint working at a local garden center would rekindle my love affair with roses? Over the last few months as I've watched my own reactions to the various roses, I've reached several conclusions.
Hybrid Teas Have a Place
At the garden center, hybrid tea varieties predominated, and probably three out of four customers have wanted hybrid teas. One key to successfully growing hybrid teas is being very picky about which varieties you choose or being willing to baby a pest-prone one. AARS winning roses are tested and proven to be easy choices for your garden.
Try Organic Methods
Consider trying organic pest control techniques. First and foremost, that means siting the plant correctly and preparing the soil well with compost and manure. No matter what, some roses will require some pest control. The best of the safest include a modification of the Cornell University horticultural oil and baking soda formula, the Bordeaux mixture of copper sulfate and hydrated lime, and neem oil products.
The original Cornell formula is 2 tablespoons fine horticultural oil, 1 tablespoon mild liquid soap (such as Palmolive), and 1 heaping tablespoon baking soda in a gallon of water. Optional additions include 1 tablespoon fish emulsion and/or liquid seaweed and 5 to 7 drops of liquid plant vitamins.
Be Adventurous
Experiment with combining various roses with other plants. One of my favorite combinations is the unusual 'Hot Cocoa' rose with 'Mrs. Bradshaw' geum and 'Paprika' yarrow.