February is not too early to begin planning summer colour.
Sweet Peas are a colourful, highly scented annual climber which can be started off in February. At this stage sow underglass and keep warm until they have successfully germinated. Sweet peas can then be hardened off ready for planting out usually around April. Sweet peas are half hardy annuals so will take a fair degree of cold once established. Pinch out the top growth to have multiple stems per plant and more summer flowers. For details tips and sowing advice check out How to Grow Sweet Peas.
There are also summer flowering bulbs which can be started off later February such as Dahlia and Lily. Plant only during a mild spell and bear in mind they are not frost hardy. It should take around 6 weeks or more for the top growth to emerge which should be around mid to late April. If there is a frost protect the top growth with a cloche. Planting early, with the right winter protection, will get the bulbs off to an early start. If you garden in an exposed area prone to late frosts, or with a lot of winter wet delay planting until later in March.