It can be difficult to diagnose this. So many possible variables, especially pot size, and the kind of soil in the container. But the symptoms of your allysum *strongly* suggest too much time in persistently wet soil, and root rot. Especially the last day or so. It has had lots of water, yet looks thirsty. It's wilty, and the leaves are looking dry and a little crispy. Doesn't get better when you water it. The stems are progressively brownish..... The roots have rotted/are rotting, and can no longer take up water from the soil.

The same could apply to your 'tunia. It has been such a wet spring/summer! Your zone 6 OH isn't far from my zone 5/6 MI.

Usually, we have these things in good potting soil in containers because the risk is having them dry out too much. The soil is designed to retain moisture. And we have learned to water them every few days, because they are in containers. And we certainly have pots with drainage, but only enough to prevent pooling. Container plants here are more at risk of getting too dry.

Not true this year. And both allysum and petunias would much rather get a little on the dry side rather than be overwatered. That's why they are so reliable as fairly-low maintenance border plants.

I really think that's the problem.

Thanks so much. After reading your reply I think that your assessment is correct! I panicked and gave more and more water when I should have left them alone! I will hold back on the surviving ones and see what happens. Thanks so much for your reply!