I bought some seeds of this and they were very quick to come up. But they produced very few leaves and yet they produced flowers. I was away from home for 10 days and came back to find those which I had sown in situ had died. I still have one or two in pots which I will plant out but I was rather hoping they would fill in spaces and give flowers at the same time. I am only getting single flowers on very short plants with next to no foliage. Can anyone help?