Posts: 126
Threads: 0
Joined: Jun 2005
Potatoes are usually grown as a food crop not an ornamental. If what you have is an ornamnetal with a common name of "Potato Plant" we need a better name for it since nothing comes up under that name besides the vegetable.
West Central Michigan along the lake shore.
Posts: 182
Threads: 0
Joined: Mar 2006
Could the green leaf/purple flower one be sweet potato vine? Maybe the second plant was mislabeled? I know sometimes the tags at the nurseries can fall out of the pots, and a well-meaning customer (or novice big box store employee) could have put a tag back in the wrong pot.
Not knowing exactly what the plants are, it's hard to say when to prune them. The best rule of thumb I can give is, if it seems to flower on the previous year's growth (usually in early to mid spring), then prune immediately after flowering. If it seems to grow on new growth (usually sometime late spring through fall), then prune in early spring before new growth begins. (You can actually prune at any time; it's just that pruning at the so-called 'wrong' time will lessen, rather than hopefully enhance, the number of flowers that you'll see the following season.)
The great thing about gardening is that you always get a chance to start over!