Posted: 04/05/2016 at 09:41
Lupins ...foliage now, flowers in 3 weeks or so,,then the summer stuff comes.
I grew senettii for this purpose........works well. Expensive for gap fillers though
the answer really is to grow wallflowers. They flower for a long time, provide evergreen foliage and when your cosmos or anything else is ready dig them up.
Lilies are ideal too....lovely fresh foliage almost architectural in a small way and then the flowers