What Causes The Extensive “brown-out” Of Foliage?

Question

By mid July, the foliage on my cosmos (starting at the bottom and moving upward) becomes dark brown looking dead and water deprived…..like drooping brown lace. I’ve tried a variety of irrigation techniques, times and volume of water but nothing seems to work.

Answer 1

These flowers prefer dry, hot soil. Wet soils cause infections, which is likely the case here.

I would treat the area with a fungicide, and replant. This article will help you with fungicide use:

https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm

This article will help you to know what care these plants require:

https://www.gardeningknowhow.com/ornamental/flowers/cosmos/growing-cosmos.htm