Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998
Article from Bean's Trees and Shrubs Hardy in the British Isles
'Rhododendron macrophyllum' from the website Trees and Shrubs Online (treesandshrubsonline.
Shrub, 2–4 m; young shoots and petioles soon more or less glabrous. Leaves (6.5–)8.5–12(–17) × 3–5.2(–7.5) cm, broadly elliptic, apex acute to minutely apiculate, upper and lower surfaces glabrous when mature. Flowers 10–20, in a dense truss; calyx c.1 mm; corolla white to pink, with yellowish flecks, broadly campanulate, without nectar pouches, 30–40 mm; ovary densely rufous-pilose, style glabrous. Flowering May-June. Royal Horticultural Society (1997)
Distribution United States Western seaboard
Habitat s.l.-150 m
RHS Hardiness Rating H6
Conservation status Least concern (LC)
Taxonomic note Closely allied to R. maximum though with relatively broader leaves, 2.5–2.8× as long as broad. Royal Horticultural Society (1997)
An evergreen shrub up to 12 ft or sometimes more high; branches stout and erect. Leaves elliptic to oblong, inclining to obovate, 3 to 6 in. long, 11⁄4 to 3 in. wide, tapering at the base, dark green above, paler beneath, quite glabrous on both surfaces; stalk 1⁄2 to 1 in. long. Flowers produced during May, twenty or more in a terminal truss; rachis about 1 in. long; pedicels 11⁄2 to 2 in. long, glabrous or slightly downy. Calyx small, with five, short, broad lobes. Corolla bell-shaped, with five waxy lobes, 2 to 21⁄2 in. across, rich rosy purple to pink or sometimes white, with brown spots on the upper lobes. Stamens ten, shorter than the corolla, downy at the base. Ovary covered with white, appressed hairs; style glabrous. Bot. Mag., t. 4863. (s. and ss. Ponticum)
Native of California northwards to British Columbia; introduced by W. Lobb in 1850, but now rare in gardens. It may be considered as the western form of R. catawbiense, differing in its more erect growth, in having the leaves tapered at the base, in the more rosy tinted flowers, and the often glabrous flower-stalks. The calyx-lobes in R. catawbiense are also longer, more pointed and triangular. It is quite hardy.