Sprawling plants that bloom over a long season, bearing phloxlike clusters of blue or white flowers at branch ends. Prune these shrubs back hard in late winter to control their growth and keep them compact. For other plants that are called plumbago, see Ceratostigma.
P. auriculata. CAPE PLUMBAGO. Evergreen or semievergreen. Zones CS, TS; USDA 9-11. Native to South Africa. Makes a mounding shrub to 6 ft. tall, 810 ft. wide; or, if tied to a support, grows as a vine to 12 ft. or more. Oblong, 1- to 2-in., light to medium green leaves. Inch-wide flowers. In seedling plants, blossom color varies from white through pure light blue to sky-blue; best way to get good blue color is to buy cutting-grown selections such as 'Royal Cape' or 'Imperial Blue'. 'Alba' and 'White Cape' are white-flowering forms. Blooms from spring through summeror nearly all year in warm, frost-free locations.
Evergreen where frosts are absent or light; heavy frost can burn new growth and blacken leaves, but recovery is fast. Prune out any damaged parts when frost danger is past. Not fussy about soil type but must have good drainage. Good cover for bank, fence, wall; good background and filler plant. Does very well in pots. Tolerates light salt spray. Not browsed by deer.
P. indica. SCARLET LEADWORT. Evergreen. Zones LS, CS, TS; USDA 8-11. From Asia. Thin-stemmed plant to 6 ft. high, 3 ft. wide, with smooth, oval, medium to deep green leaves to 4 in. long. Blooms from winter to spring, bearing long-tubed, deep rose-pink to red flowers in clusters to 1 ft. long.
P. scandens. DOCTORBUSH. Evergreen. Zones CS, TS; USDA 9-11. Native from Florida to Arizona, south to Central America. To 4 ft. or more high and wide. Oblong leaves to 4 in. long are deep red when new, maturing to medium green; nearly all foliage turns red in late fall and winter. Blooms year-round (with a short break during hottest part of summer), bearing typically white (sometimes blue-tinged) flowers nearly 1 in. wide. Particularly striking when white blooms appear in combination with red leaves. With this species, hard pruning both controls size and encourages the growth of colorful new foliage. Accepts most soils. Can get powdery mildew in late summer but doesn't seem to be greatly harmed by it. Attractive ground cover. 'Summer Snow' has pure white blooms.