Filling in Gaps in the flower border

When I plant up chimneys and hanging baskets in the Spring I often have a few plants left over which I stuff in odds and ends of pots.  They come in very handy for filling gaps in the borders as the summer goes on.  Stuff dies down or new stuff isn't as big as I want it in its first year and I get odd spaces so I shove in a pot of annuals to fill the gap.  I noticed a space around the bird table this year so I hung two very small pots from it (with S hooks) with just one Surfina in each and stood a clay pot with a white geranium in it at the base and it looks much better for it.