Try some heathers ,it is a bit early for seedlings still chance of frosts but towards the end of may petunias make a lovely display in pots and for lasting year round a nice acer the leaves change colour during the year also for now polyanthus they come in lovely colours also heathers can be bought for flowering at different times of the year so you always have a bit of colour then of course bulbs for early spring next year ,get some advice from your local garden center if you are unsure.Good luck