annuals in containers: plants dry up in late summer

I grow lots of annuals in containers. generally very successful. I have noticed that certain plants fairly quickly dry up in late summer, even though moisture is adequate. Happens with some cosmos ( "Unique" and "Antiquity") and multiflora petunia . I suppose this is just natural, but i do wonder if one can delay or prevent it. BTW: i believe i have read that petunias can be cut back
Thanks for any information.
Jim W - Lancaster MA

I've seen petunias come back, but it takes awhile...Cosmos probably just expend all their energies into blooming, then die off....I've seen this happen in my gardens with the small ones...the larger cosmos, some can top 4', seem to go until frost.....

I started using the water saving gel crystals, best thing I EVER did for my containers

been using polymer gels for years.. just love them!!!

thanks very much for suggestion on the polymer crystals. .... question: does one have to be careful about OVERwatering?
BTW: not too surprising but the heavy-blooming zinnias have the problem to a degree, but the "profusion" ones appear to be the longest lasting for me

easiest way to check if it needs water stick your finger in the soil down about an inch if it feels damp it doesn't need water

one suggestion about the gels.. expand them first.. then add to your containers.. I made the mistake one year and added them in dry.. and they gooezed out everywhere.. like the blob

thanks for feedback

You have to keep faithfully deadheading annuals and feeding them. They bloom a lot and get pretty hungry. Once they flower and set seed, that tells the plant it's all over and it can croak now.
Martha

yes indeed - nature of annuals - hard to keep ahead of the cosmos with deadheading - but i did have some that were still nice and green and still blooming a week ago -