I put perennials in my flower box and they did not do well. We had a sufficient amount of rain and the flowers died. I am thinking that it had to do with improper drainage. Please suggest what I could do in the future to prevent this. Thanks.
Plants in flower boxes need to be watered daily. If they only received rain as water, this is likely why they did not do well. In the ground, plants can send roots deeper and wider to find water and the water does not evaporate as quickly from the ground as it does from containers.
If you still feel that it was a drainage issue, you can line the bottom of the flower box with stone. This will help provide additional drainage.