Oregon Grape Rust

How to Treat Mahonia Rust

Oregon Grape Rust-oregon-grape-flowers
Oregon grape flowers

The Oregon grape is native to much of the western United States but grows mostly east of the Cascades from Central BC southward. This low-growing evergreen shrub produces pale yellow flowers form in long racemes of about eight inches. The leaves are blue-green turning dusky maroon during winter.

The Oregon grape ( Mahonia aquifolium) is a species of flowing plant in the family Berberidaceae, there are said to be some 700 known species. The common names of the Oregon grape are holly-leaved barberry, creeping barberry, tall Oregon grape, and Oregon holly grape.

It’s said that this plant is used to “treat gastroesophageal reflux disease, stomach upset, to cleanse the bowel, us as a bitter tonic, to treat infections, the cold, the flu, syphilis, herpes, hepatitis, etc”…

If you’re thinking of installing the Oregon Grape then make sure and provide the proper spacing, the Oregon grape can reach heights of 6-8 ft with a spread of 3-5ft. The question I received was about the Oregon grape rust, below we will be addressing this question of how to identify and treat this condition so that your Oregon grape can continue to grow healthy and beautiful.

Oregon Grape Rust

Oregon grape rust or mahonia rust is an infectious disease that is caused by fungi, during the early spring months when the weather is cool and dump makes it favorable for this disease to develop. If you suspect that your Oregon grape has fallen to this disease then look for signs of reddish spots on the upper leaf surface.

If this disease is not treated immediately or allowed to persist will cause pustules that are brown in appearance to appear on the underside of leaves that are mature. Tiny holes will also be seen on the leaves, in extreme cases, the leaves will become distorted followed by premature leave defoliation or leaf drop.

How to Treat Oregon Grape Rust

Treating Oregon grape rust is simple, avoid overhead irrigation, and don’t allow water to make contact with the plant’s leaves. Water around the base of the plant or at ground level. Remove all infected leaves from the plant, leaves that have fallen to the soil surface can be raked and properly disposed of. Infected leaves should not be used in a compost bin.

Oregon Grape Rust with Chemicals

Wettable sulfur is a sulfur fungicide, apply this to your Oregon grape during the wooly bud stage or the delayed dormant stage during the late winter months. It is called the wooly bud stage because the leaves at this point are clustered in wooly-looking buds, avoid using fungicide during rainy weather which can wash the sulfur before it has time to work. Before applying, the fungicide should be diluted with water and sprayed on Oregon grape according to the manufacturer’s label for the best results.

Oregon Grape Cultivars

Another option is to cultivate or grow rust resistance species.

The final word on Oregon rust

Taking care of Oregon grape rust is that simple, these easy steps are effective and will help in encouraging your plant to bounce back to good health. If you have had issues with your Oregon grape then look for these symptoms, it may be that your Oregon grape has this rust problem that can easily be solved.


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About the author

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Norman loves being in the garden, both at home and for his job....
he is 'Natures Little helper' being outdoors, growing his vegetables and flowers from an early age.
Now having spent over 22 years in the profession he want to give some of his knowledge to others...
his vast array of hints and tips you will find scattered over this site will help you no end growing plants in your garden.