I have had pritty good luck with my dahlias that are planted in 1/2 whiskey barrels. As they are getting bigger and taller they seem to have lost that full foliage look. Is that normal? Also, one of my 1/2 whiskey barrels is placed on cement and it doesn't look good now. I'm wondering if the cement under it doesn't allow drainage. It's either that or it's not getting enough water. Any ideas?