Hi Poppy, the yellow one is a dahlia. it is a tuber and you can keep it over the winter in its dormant stage if you live where it freezes. (in a place like your basement, that doesn't freeze) the next is a petunia. looks as if it could be a double flowering variety. It is an annual. keep the flowers pinched off, including the newly forming seed pod, and it will flower all summer long. the last is a geranium. Once the flower is spent clip or pop off the whole flower stem, clear back to the stem of the plant. On all your summer flowering plants keep the flowers and seed pods pinched off. If they "think" it's time to produce seeds because the flowers were pollinated, they will spend all their energy forming seeds rather than the pretty flowers you are looking for. Now if you want the seeds .... let nature take its course. They are all pretty flowers also. good choices.
