Rhododendron johnstoneanum
Botanical Information
Family | Ericaceae |
Genus | Rhododendron |
Species | johnstoneanum |
Synonyms | Rhododendron parryae |
Category | Woody |
Type | Shrub (evergreen) |
Origin | Manipur, Mizoram, north east India. |
Details
USDA Hardiness Zone | 7a - 8 |
USDA Hardiness Ref. | |
Canadian Hardiness Zone | Requires cold season protection under glass. |
Canada Hardiness Ref. | |
RHS Hardiness Zone | H5 - H6 |
RHS Hardiness Ref. | |
Temperature (°C) | -12 - (-15) |
Temperature (°F) | 10 - 5 |
Height | 3 metres |
Flowering Period | May |
Description and Growing Information
Shape | Spreading. |
Landscape | City and urban courtyards and gardens, as a groundcover and in informal gardens. |
Propagation | By seed, semi-hardwood cuttings, layering or grafting. |
Cultivation | Grow under partial shade in moist but well-drained, humus-rich acidic soil. |
Pests | Caterpillars, aphids, vine weevil, leafhoppers, lacebugs and scales. May be susceptible to rhododendron petal blight, rhododendron bud blast, powdery mildews and silver leaf. |
Notable Specimens | Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. |
Habitat | Found at elevations of 1800-3600 meters. |
Bark/Stem Description | Bristly twigs, attractive reddish brown peeling bark. |
Leaf Description | Dark green hairy leaves, broadly elliptic to elliptic, up to 10 cm long, margins usually bristly. |
Flower Description | Funnel-campanulate, sometimes fragrant, white, cream or pale greenish-yellow, often blotched yellow or flushed pink. Truss holds 2-5 blooms. |
Photographs
![Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.](photos/Rhododendron-johnstoneanum-tren-FRM1.jpg)
Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.
![Rhododendron johnstoneanum, leaf, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. Rhododendron johnstoneanum, leaf, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.](photos/Rhododendron-johnstoneanum-tren-LF1.jpg)
Rhododendron johnstoneanum, leaf, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.
![Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.](photos/Rhododendron-johnstoneanum-tren-FLW1.jpg)
Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.
![Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.](photos/Rhododendron-johnstoneanum-tren-FRM2.jpg)
Rhododendron johnstoneanum, form, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.
![Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom. Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.](photos/Rhododendron-johnstoneanum-tren-FLW2.jpg)
Rhododendron johnstoneanum, flower, Trengwainton Garden, Madron, near Penzance, Cornwall, United Kingdom.