Corydalis 39canary feathers39 is a favourite hardy perennial for brightening dampened shady spring borders it has dainty tubular flowers over a long period that appear on upright stems atop clumps of blue45green ferny foliage an easy to grow woodland plant in warmer spots this plant may become dormant during summer with the foliage reappearing during autumn height 30cm 40123441 spread 60cm 40243441