Plectranthus amboinicus (Country Borage)


Botanical Information

FamilyLamiaceae
GenusPlectranthus
Speciesamboinicus
SynonymsColeus amboinicus, Coleus aromaticus, Coleus carnosus, Coleus crassifolius, Coleus subfrutectosus, Coleus suborbicularis, Coleus suganda, Coleus vaalae, Majana amboinica
CategoryPerennials, Tropicals
OriginAfrica - Burundi, Angola, Tanzania, Mozambique, Natal, Swaziland. Arabian Peninsula - Yemen, to India

Details

USDA Hardiness Zone10
USDA Hardiness Ref.
Canadian Hardiness ZoneRequires cold season protection under glass.
Canada Hardiness Ref.
RHS Hardiness ZoneH1c
RHS Hardiness Ref.
Temperature (°C)5 – 10
Height50 - 100 cm

Description and Growing Information

General DescriptionAn evergreen perennial plant with lemon-scented, thick, fleshy, sprawling stems and leaves.
PropagationBy seed: sow in well-drained soil, covering lightly with a thin layer of sand, and place in a warm but shaded spot. The seed germinates in about three weeks. Stem cuttings or division.
CultivationGrow in in full sun or shade in a fertile well-drained soil.
Notable SpecimensQueen Sirikit Botanic Garden, Mae Rim District, Chiang Mai Province, Thailand.
HabitatRoadsides, waste places and on river banks; at elevations up to 1,500 metres.
Bark/Stem DescriptionLemon-scented, thick, fleshy, sprawling stems.
Leaf DescriptionPetiolate with blades fleshy, broadly ovate to sub-orbicular, rhombic, or reniform, 4-10 cm long, 3-9 cm wide, rounded to truncate and then often long-attenuate at base, obtuse to rounded at apex, coarsely crenate to dentate at margins or entire toward base, densely appressed-pubescent above and beneath; petiole 1-4.5 cm long.
Flower DescriptionTerminal, spicate, 10-20 cm long, densely pubescent, the verticils 10-20(or more)-flowered, subglobose, the bracts 3-4 mm long, hirsute and glandular; pedicels slender, hirsute, to 5 mm long; calyx campanulate, 1.5-4 mm long, hirsute and glandular, the upper lip erect, broadly ovate-oblong, the other teeth narrow, acute; corolla pale blue or mauve to pink, 8-12 mm long, the tube declinate, 3-4 mm long, expanding distally, pubescent without, the upper lip to 4.5 mm long, 3 mm wide, erect, puberulent, the lower lop to 5-6 mm long, 4 mm wide, concave; stamens with filaments mostly fused into a tube around the style.
Fruit DescriptionA small nut, smooth, pale brown, 0.7 mm long, 0.5 mm wide.

Photographs