Monday, November 24, 2014

Treatments for Leaves on Rose Garden Plants

Different diseases can attack the leaves of rose plants, but most of these diseases, such as powdery mildew and rust, can be prevented with proper watering and pruning. Rose plants require one inch of water every week and should be watered at the base of the plant. Spraying water over the entire plant encourages disease problems. Deadheading, the removal of dead rose blooms, also helps prevent leaf diseases. Diseases and larvae can hide within the dead blooms and infect the rest of the plant.


Aphids, red spider mites, spittle bugs, and rose slugs are a few of the pest that can infect a rose plant. Most of these pests, such as spittle bugs, can be removed simply by hosing down the leaves and knocking off the insects. Aphids can be removed by spraying the rose plants with hose water and misting the leaves with an insecticidal soap or horticultural oil made specifically for roses. Rose slugs are the larvae of the sawfly that eat holes in the leaves of the rose plant. To get rid of rose slugs, spray the tops and undersides of the leaves with an insecticidal soap for roses containing Pyrethrins.

Powdery Mildew

Powdery mildew covers the leaves of the rose plant with a white powder. It rarely kills rose plants, but it will affect the leaves and blooms. To treat, mix two tablespoons horticulture oil into one gallon of water and spray the entire plant. To prevent the mildew from returning, spray the leaves every ten days during the growing season.

Black Spots

Black spots on rose plant leaves are a fungal disease caused by either black spot or Cercospora leafspot. The fungal disease is brought on by warm, wet weather and can cause the rose plant to die. Begin treatment by removing any leaves that show black spots. Thin out remaining leaves to allow the plant more light and air circulation. Remove all the debris from under the plant and add a one inch layer of mulch around the base of the plant to protect it from fungal spores in the dirt. In severe cases, all the leaves may need to be removed. To encourage new growth, give the rose plant a weekly feeding of fish emulsion fertilizer made for house and garden plants.


Rust is an orange-red fungus that grows on rose leaves. Sanitation is the key to getting rid of this fungus. To treat, remove and dispose of any leaves that show signs of rust. Remove all leaves that are within 18 inches of the ground to prevent further infection. Increase air circulation and sunlight by thinning out the leaves on the plant. Keep the plant free from all ground debris. Add an inch of fresh mulch around the plant and replace it every three months to prevent reinfection.

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