What are the purple blotches on my peonies? – Youngstown Vindicator

Q: My peonies have white all over the leaves, plus some purple spots that are dying. Can I treat them? Will they be OK next spring?

Valerie, Berlin Center

A: The wetness earlier this year, the heat and humidity have all contributed to the diseases you are seeing this late in the season on peonies. But they will be fine for next year.

In general, peonies are vigorous plants. They emerge quickly and give us beautiful blooms by the last day of May. But just because they bloomed beautifully does not mean they will be healthy during the entire growing season.

Remember, they require full sun, good drainage, adequate air movement and full sun (yes, that is worth repeating). Peonies can survive in partial sun, but it affects their ability to have dry leaves quickly in the morning that helps reduce fungal infections.

There are two prevalent fungal diseases this year (and probably a few more):

Peony leaf blotch This is just like it sounds. There are large, ugly blotches that start out red and turn purple, then brown. The leaves really get hammered with this disease and look terrible.

Powdery mildew If your plants look like they have been sprinkled with baby powder, this is the culprit. It covers the entire leaf surface in most cases.

So, what can you do?

Thin the canopy to increase air movement. Use a sharp pair of pruners. Destroy the plant material you remove.

Consider moving the plants to a new location and sharing any extra you dont need. Division is a good way to thin the canopy by spacing plants out and allowing for more natural air flow through the plant next season by doing so.

Remember, they need lots of space, so dig a hole about 18 to 24 inches across. Be sure the red-colored buds on the roots are about 2 inches below the soil.

There are fungicides you can use. See the factsheet link below for list and instructions. Read the label and follow all directions. It is too late for this season, but you might consider this for next year.

Cut the plants back to the ground (and maybe 1 inch below the soil surface) sometime in the middle of September. Again, destroy the plant material you remove. Im cutting mine down this week as they plants have already stored enough energy for next season.

Working with your plants in this way will ensure beautiful blooms for years to come.

More details can be found on this Penn State Extension Factsheet: http://go.osu.edu/sickpeony.

Barrett is the Ohio State University Extension educator for agriculture and natural resources in Mahoning County. Call the extension office hotline, 330-533-5538, 9 a.m. to noon Mondays and Thursdays to submit your questions.

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What are the purple blotches on my peonies? - Youngstown Vindicator