Sweet Williams are usually grown as biennials, which means they flower in their second summer and then die. Sometimes they will flower again another year and sometimes they disappear. If you are growing them in pots it isn't worth trying to keep them. I would discard them and put in some dahlias for the autumn.

When you garden in containers your watering regime will have to be second to none from March through to September because the water needs of potted plants are so much higher than plants in the ground.

Also, the winter losses will be higher when you're gardening that way so be prepared to move them all into a greenhouse or conservatory before the first frosts come or you'll lose a lot.

Good to hear about someone just starting to get interested in plants. You've started a lifetime's interest,
Lizann. And this is a great place to get help.