Hi pinksand,

Try spraying your zinnias frequently with GreenCure. GreenCure is safe and effective against a lot of foliage diseases, including Powdery Mildew.

Apparently your zinnias were falling over before the Powdery Mildew made a showing, so you might try staking at least some of them.

"Should I have trimmed them back mid-season to keep them from getting so tall? They aren't leggy... "

Actually, I like my zinnias tall, because I don't have to stoop over to pollinate or cross-pollinate them. (I am an amateur zinnia breeder).

If you could post some kind of picture of your zinnias, it would give us a better idea of what your zinnia problems are.

ZM
(not associated with any product or vendor mentioned or linked)

hey zenn-ny ... you are way beyond amateur ...

anyway ... back in the day.. when i was a newbie.. at gardening.. i fert'd everything...

and lots of things fell over ...

how much fert did you use... is there any indication your soil is so deficient of nutrients.. that you needed such??? .. and what formula of fert ...

sometimes we complicate our lives.. by over thinking things ...

ken

Just by way of discussion, I plant the tall zinnias every year. Some years, I pinch them back to make them bushy, other years I don't. The truth is, I see very little difference in them by this time of year. The one thing that seems to help them not fall over is to plant them in groups of 3 or 4 plants, spacing them about a foot apart. They seem to support one another further into the fall. And, you get more blooms close to each other at the same time.
My growing season is so long, though, that sometime in the next month or so, I will pull the plants altogether. They are starting to get fungus spots on the leaves and will eventually look too ratty to bear. Deadheading delays the end, but it will inevitably come before frost.

I'm sorry it took me so long to get back! I took some photos of the zinnias but my personal computer died and I haven't been able to upload them :( I actually didn't fertilize them at all, just a layer of spring compost. Maybe that's where I went wrong? I haven't had my soil tested but they are in a new bed I formed this spring by lasagna gardening. The soil seems to be rich, easy to dig into, and full of earth worms. My other annuals planted at the same time are very healthy and lush.

I staked the zinnias that were laying on the ground. There are 5 of them spaced about 1' apart in a grouping, but some fell in the wrong direction. They're all still putting out beautiful large blooms, but the powdery mildew has turned the leaves into a nasty mess! It sound like I need to get some GreenCure! Thank you for the recommendation. I'll need to be more proactive next year, I'm still learning... I guess going through these experiences is a necessary evil in figuring out what works?!

I'm wondering if some varieties of zinnia are more mildew-resistant than others. I planted Botanical Interests' Fireball Blend this year and have had no problems with mildew so far. I realize, of course, that we get much less rain than you do in Maryland. But we've just had almost a week of rain here, and I'm still not seeing mildew.

It's probably too late to do much about your mildew problem this year. But next year, you could try a solution of baking soda and water to control mildew as soon as it appears. The solution worked quite well on my zucchini's mildew.

Here is a link that might be useful: mildew control