Growing roses in Houston, Texas can be challenging due to the climate – 100 plus degree temperatures that last for weeks, torrential rains, and lots and lots of humidity. This can make for an environment that encourages many diseases to attack your roses vigorously. Fortunately, with vigilance and a little extra care, you can prevent, stop or cure many of these common rose afflictions. For a guide to the most common diseases that may strike your Houston, Texas rose garden, and what to do about them, see below.
Rust. Named for the rust colored spots that occur on the underside of your roses’ leaves, warm days and cool nights provide a good environment for this common rose disease to flourish. Winter prunings (damaged and dead wood) are a common source of this disease, so be sure and clean these up. Use a good fungicide spray to help prevent Rust in your Houston, Texas rose garden. Remove and discard any affected leaves immediately.
Black Spot. As its name implies, look for black spots on the leaves and stems of your Houston, Texas roses. Eventually the leaves will turn yellow and drop off. Spraying in early spring (February and March) will help to prevent this common disease. If you see any black spots on the leaves or stems of your roses, trim them off and throw them away. Wetting both the top and underside of the leaves of your roses at least once a week with a good fungicide spray will help prevent this common rose disease. For the hot, dry periods of Houston, Texas weather, less spraying is required.
Powdery Mildew. Look for a grayish white fuzz (mold) on flower buds and new leaves. Low rainfall and high humidity at night are the perfect conditions for this disease (very common conditions in Houston, Texas.) Spraying your roses with a mixture of Murphy’s Oil Soap (1 tsp.), baking soda (1 tsp.) and water (one gallon) can help prevent powdery mildew. Spray every two weeks for a good preventative plan of this common disease in Houston, Texas.
Downey Mildew. Look for purple or dark brown spots with yellow edges on the leaves of your Houston, Texas roses. This is a more serious but less common rose disease, but you can cut your risk of this by watering early in the morning, as it needs water to spread. Cut off any infected flowers and leaves immediately and treat your plants with fungicide to help control this disease.
General Disease Prevention Tips. Here are some simple tips to help you keep your Houston, Texas roses disease free.
Plant healthy plants. Only plant healthy roses so they have a fighting chance. An unhealthy plant is more susceptible to disease.
Plant disease resistant roses. There are many, many disease resistant roses that will thrive in the Houston, Texas climate. Aloha, Belinda’s Dream, Duchess de Brabant, Climbing Pinkie and Hot Coca are just a few of the roses you can plant that are very resistant to common diseases.
Prune, fertilize and water correctly. All of these contribute to the health of your Houston, Texas roses, so be sure you are not over or under pruning, fertilizing or watering your rose plants. Also be sure to water the roots, not the leaves, as moisture can spread certain diseases such as Downey Mildew.
Provide good air circulation. Don’t let your roses crowd each other to ensure the air is circulating properly.
Be vigilant. Inspect your Houston, Texas roses regularly – leaves, flowers, etc. This way you will spot any common problems before they become too severe.