I'm looking for a colourful flower to add to a large green container on my deck. I've looked around, but am feeling dissatisfied. The pot gets morning sun, then dappled shade around midday, then full shade the rest of the day. I would like the flower to be fairly low, not to rise too far above the base of the draceana at the back of the pot....and to ooze out a bit a little over the lysimachia in the front. I bought some royal impatiens this morning, but they seem too clumpy. Any suggestions? I can include a photo if it helps. Thanks!