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.
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
What steps can I take to remedy poor drainage? I am having to put off watering my plants for two weeks at a time in hot weather as the underneath is still damp. Are there any recommended shrubs and plants which do well in poor drainage?
There are many ways that you can amend the soil to help it drain better. This is the preferred way. Here are some articles that will help:
https://www.gardeningknowhow.com/special/organic/how-to-easily-improve-your-clay-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm
The alternative will be to find plants for the area. This may not be as good of an option as fixing the area, but it will ensure that something can grow there. This article will help:
https://www.gardeningknowhow.com/ornamental/water-plants/wgen/water-tolerant-plants.htm
I bought the soil at a landscaping place they said it was for gardens but I just can't keep it moist for my new plants I added peat moss
Peat moss will, likely, make the situation worse! In fact, this is probably why the soil loses moisture so fast. Once peat dries out, it becomes hydrophobic. Once this happens, it will be hard to get it to absorb much water.
For this reason, I prefer coco-coir. Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/peat-moss-alternatives.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/planting-in-coco-peat-media.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/improving-garden-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/garden-soil-information.htm
We have had a lot of issues with standing water in the front at the house where the bushes and flowers were. We had gutters installed hoping that would solve the problem. We previously noticed when redoing the front that there is a lot of clay. We added black cow before planting. Well we still have the issue and it ruined all we had planted. So we were at square one. We added more black cow, re planted, and we are still having the same issue of water standing in areas around some of what was planted, and it's just not draining. Some areas are puddles. So we need to raise the grade? How? What can we do to fix this because we are wanting to sell the home but when we redo this again we want it to be the last time. Thank You in advance.
Tilling, and amending will be the best option. Unfortunately, cow manure compost on its own will be too thick, leaving you with the same problem. Adding earthworms will help, drastically, as well. Here are some articles to help you:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/improving-garden-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/macro-and-micro-elements.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/making-sure-soil-drains-well.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm
https://www.gardeningknowhow.com/special/organic/how-to-easily-improve-your-clay-soil.htm
These roots pest had spread out in the soil and eating the nutrients in the soil intended for the plants and become dominant till the plants will die. Please help how to kill these roots thru chemicals applications? Thank you with regards to this matter. Regards, Sam Bayogos
This can be an issue. Here is an article to help you deal with tree roots in your yard:
In the future, please refrain from putting in your personal information, as these questions are public. I will remove it for you, this time.
A huge tree was removed and the stone well that surrounded it was filled with gravel. What can I plant around the stone well that will cover the stump? There are some tree roots outside the well. Would large leaf hosta work? I don't need to conceal all it, but just dress it up a bit
I would not, unless there is a bit of shade in the area. They will be sensitive to full sun. There are several options for you. I will include an article for a zone lower than yours, in case you decide to grow some of these plants in container nearby, as well:
Powdery mildrew went through my flower garden this summer and killed all my zinnias and perennial salvia. I have removed all the affected plants; now do I need to treat or replace my garden soil in order to get rid of this fungus, or it it strictly airborne?
No, you don't need to treat the soil, but make sure all the leaves that dropped are picked up from the ground and placed in the trash.
It is airborne like you said.
https://hgic.clemson.edu/factsheet/powdery-mildew/