If you're a proud grower of dahlias, you may be a little concerned that they've not yet shown any sign of flowering. "I grow dahlias in pots because my gardening space is quite tiny and they're brilliant for that. "So from now, July through August, September, October and into November, you'll have a pot full of blooms," finishes Tom. Then all you'll need to worry about is overwintering your dahlias once the frost does arrive. As your dahlias begin to flower, you'll need to master how to prune them for more blooms.