I have planted flower towers for the last 2 summers. I used Petunias the first year which became leggy, even though I was diligent in deheading the plants on a regular basis and didn't survive the summer. The 2nd year I used Impatiens which developed a fungus and barely made it through the 4th of July. What other flower would you recommend I plant this year? I was disappointed in the results not to mention the time and expense involved.