Rust on Ironweed

Hamilton, OH(Zone 6a)

When I returned from vacation my Vernonia gigantea was riddled with rust. I have grown this plant for years and have never encountered this before. Does anyone have a suggestion on how I can prevent this in the future?

Elgin, IL(Zone 5a)

I'm sorry I just noticed this thread.

An effective (and organic!) remedy is elemental sulphur. Bonide makes it, but you must apply it when the temperatures are below 80 degrees, and you must PREVENT it!

Get a concentrate, dilute it and put it in a spray bottle. Cover the whole plant.

This also works for powdery mildew and black spot. I use it on my roses and it keeps them disease free.

Lake Toxaway, NC(Zone 7a)

I got a lot of seed off my neighbor's field of ironweed but never got any to germinate. Can you give me some advice?

Elgin, IL(Zone 5a)

I found a site that indicates that Ironweed germinates best at a temperature of around 65 degrees and is best sown outdoors. It needs light to germinate, so barely cover it. You will need to keep the seed moist. It should take 14 to 21 days to germinate.

I suspect from these instructions that transplanting it is difficult. Like balloon flowers. What I do is start seeds like this in small pots, like the kind annuals come in at flower centers, and plant the entire pot. I have had very good luck germinating things on my south facing patio. The catch with sowing it outside is wind and creatures, but if the have a protected location you could put the seed out and monitor it. To keep squirrels from playing with it, after you sow it use a pepper grinder to put fresh pepper (not dried) over the site.


Lake Toxaway, NC(Zone 7a)

My neighbors have a whole field of these. To prevent them from spreading, they mowed them down. I tried to grow seed one year but didn't know much about them. I thought I'd ask to dig one or two up next spring, but I'm glad I ran across this thread. I'll suggest a solution next spring. Thanks Donna.
DG is a great place!

Post a Reply to this Thread

Please or sign up to post.