Dwarf Plumbago; aka,
Blue Leadwood or Leadwort
"Have covered part of this old wall, entwined
With fair plumbago, blue as evening heavens behind."
-Alan Seeger
(1888-1916)
(1888-1916)
Dwarf Plumbago (Ceratostigma plumbaginoides) blooms at the minimum late summer & early autumn, but potentially from June through October, with gorgeous bright blue flowers.
It will still be in flower as the leaves turn a lovely bronze color in autumn. The second photo, from October, shows the leaves just beginning to turn color.This native of China is hardy for zones 6 through 9, possible for zone 5 with winter mulch or a protected location.
In Zone 8 it is semi-evergreen through winter, though whatever is left by winter's end should be trimmed to the ground to make room for new growth. In frostier zones it will die back on its own. It likes moist well draining soil to partial droughtiness, but does not like soggy conditions.
In spring & early summer before flowering, the foliage has a shiny fresh look even in a full-sun rock-garden. It grows to six inches or at most a foot in height, forming a dense mat.
It can be a fine alternative to English ivy or vinca, forming a rhizomitously spreading weed-suppressing groundcover. But it can be a little aggressive against like-sized or smaller groundcovers.
It's one of the best foliages for holding its looks in a wide variety of conditions. It can tolerate sandy to clayey soils, full sun to bright shade, & droughty conditions. It blooms a little less well in bright shade but nevertheless adapts well to areas under large shrubs in conditions that suit few perennials.
Dwarf Plumbago is great as an edging plant over spring bulbs, because its spring foliage emerges somewhat late, after early spring bulbs are finished flowering & beginning to die back. It will cascade off a wall or from out of a container.