Downy Mildew on Sunflowers

(Zone 5a)

Besides the sunflowers that keep reseeding themselves in this spot, I spread some seed taken from a nature area this spring. I have no idea what those are and I am not sure any came up. I had also planted some Heliopsis helianthoides (Early Sunflower) after cold stratification, but have not seen any sign of this sprouting. (I have had a terrible time starting from seed. )

When I went to search for images of leaves that look similar to what I have been seeing, I came across this article.

I just looked under the leaves of the odd looking ones. Not all of the sunflowers are infected, but enough. Am I right to assume that continuing to grow sunflowers in this spot is a bad thing? How should I dispose of these currently growing? Trash? Burn?

What types of natives can be planted in this spot that would not be effected by downy mildew? From those, I will try to find what best suits our area.

I planted a Bee Balm plug near this area, but not among where the sunflowers grow. I tend to plant a little in different spots to see what areas do best and if something thrives, I plan to put more in that spot later. That's another topic, but I hope it will not be effected by the mildew.

Thank you for any help.

Thumbnail by Chillybean
Vienna, VA(Zone 7a)

I don't know anything about this type of mildew other than what I read in the article, but I think it would be best to put the sunflowers in the trash to minimize the spread of the disease.

According to the article, the disease affects plants in the Compositae (Asteraceae) family, so you might be okay planting anything not in the Aster Family.

Monarda (Bee Balm) is in the Lamiaceae family, so it probably won't be affected by the mildew that's killing your sunflowers.

Bee Balm is often plagued with mildew problems of its own; however, it doesn't seem to be the same type of mildew and, in my experience, it mostly affects their appearance.

(Zone 5a)

Thank you for your reply. I'll get them in the trash. I'll have to do some research to see what would grow well in that spot. I always enjoyed the bright yellow from my kitchen window.

On another note, I just noticed my Prairie Pussytoes belong to the Asteraceae family. I planted some this spring. I hope because it likes dry conditions, this downy mildew will not cause it problems. It is in an spot far from the sunflowers.

Vienna, VA(Zone 7a)

Good luck!

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