Rose Diseases: Identification and Prevention Guide

Spring has sprung and now is the time to start planning which plants should be planted in the garden and which ones need a little “pick me up” after the colder months. Roses are one of the most popular choices of this season for many states around the nation however can be one of the hardest to keep healthy. For those gardeners that have already planted roses but are having issues with a lack of aesthetic charm, here are some tips to assure that your roses do not have any sort of rose diseases and stay healthy.

Common Rose Diseases

Black Spots

This fungal disease is usually found on roses that are planted in damp conditions. A gardener will see circular dark brown or black spots with fringed edges on the leave or stems. These leaves will turn yellow and then drop off the plant. To prevent black spotting, it is important to choose the more resistant rose variety in your area, double-check the zones on each rose bush. In addition, as a garden center representative in your area what the best choices are for your zone. After choosing the best variety for your area, choose a location that is sunny, has good airflow, and will not get too much moisture throughout the day. If already infected, make sure to mulch which aids in the prevention of spores around the plant. In addition, remember to snap off the infected leaves. Also, a mixed solution of one tablespoon of baking soda and one tablespoon of vegetable oil per gallon of water can be sprayed on the leaves. This should only be done sparingly though because it can affect the soil pH.

Powdery Mildew

This second fungal disease spread by airborne spores which were has subsisted throughout the colder months on the leaves and leaf buds. A gardener will see a white or gray powdery coating on the leaves, shoots and flower buds. In reaction to this powdery fungal disease, buds may not open and leaves will drop to the ground. Again, the roses need to have a sunny, full air-flow location in the garden. Washing the leaves and flowers in mid-morning however assure that the leaves are dry by nightfall. If already infected, remove the infected leaves and flowers throughout the season. If there is sever spreading, the baking soda mixture used in the first disease will assist this disease also.


This is the third most serious fungal disease that a rose plant can have that is spread by nature through the wind and water. Since it thrives in colder regions and loves moist conditions, this disease can last throughout the duration of the winter months. A gardener will see bright orange pustules on the stalks, leaves, or branches early in the spring. In the summer months, the leaf pustules will appear yellow-green and finally black. Since rust is very difficult to control, prevention is the best solution. Stop it before it even starts. Just as with the other diseases, it is important to purchase a quality rose that has no signs of swelling. Control the water around the rose bushes, using drip irrigations or soaker hoses that can be purchased at most gardening centers. Again, prune the leaves and stalks once signs of disease are seen.

Crown Gall

This is a bacterial disease that affects the stems and roots of a rose plant. A gardener will see large, deformed growth near the crown or on the roots. If no prevention measures are taken, the plant will die. The best time to assure that a rose is healthy against this disease at the moment of purchase. Thoroughly check out each rose plant that is a purchase for early swelling. In addition, pay special attention to the soil line and make sure there is no wounding. During the colder months, make sure winter protection is placed on the plant. If a plant does not survive through the duration of the winter, remove the plant and soil. Once it has been infected, there is no turning back. If part of the plant has been infected, it may be possible to control the healthy side away from the disease if the plant is large enough. When cutting the infected plant, make sure to sterilize the cutting tools with bleach and water to make sure no other plants are infected.

Theresa Lien
Theresa Lien
A professional writer who has specialized in houseplants and indoor gardening. She's had experience with outdoor landscaping too, having written about plants that grow well on balconies and patios as one of her previous articles for Wohomen.


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