Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998
New article for Trees and Shrubs Online.
'Rhododendron groenlandicum' from the website Trees and Shrubs Online (treesandshrubsonline.
Erect shrub, 0.5–2 m; young shoots ferrugineous-lanate. Leaves 1.2–6 × 0.5–1.5 cm. Linear-elliptic, margins revolute, upper surface dark green, lower surface with a thickly ferrugineous lanate indumentum that usually conceals the midrib, epidermis papillose covered with short white setulose hairs, scales dense, rimless, golden, intermixed with red-brown glands; petioles 1–5 mm. Flowers numerous, in a loose terminal umbellate corymb; calyx minute; corolla white, rotate, 4–8 mm; stamens 7–10; ovary glandular, style glabrous. Flowering May-June. Royal Horticultural Society (1997)
Distribution Canada Denmark Greenland United States N
Habitat s.l.-1,800 m
RHS Hardiness Rating H6
Conservation status Least concern (LC)
Taxonomic note Formerly in the genus Ledum, now considered to form part of Rhododendron. For other species formerly treated as Ledum see Rhododendron columbianum (Bean’s Ledum glandulosum) and Rhododendron tomentosum (Bean’s Ledum palustre).
Entry amended to relect the transfer of Ledum to Rhododendron, June 2022, Bean text unchanged except for name changes. JMG)
An evergreen shrub 2 to 3 ft high and as much in diameter; branches erect, clothed when young with more or less rust-coloured wool. Leaves aromatically fragrant when bruised, narrowly oblong or oval, 1⁄2 to 2 in. long, 1⁄4 to 1⁄2 in. wide, the margins much recurved, the base tapering or slightly heart-shaped, dark green with a few loose hairs above, covered beneath with a thick rust-coloured felt. Flowers in rounded terminal clusters 2 in. across, consisting of one or more corymbs; each flower 1⁄2 to 3⁄4 in. across, white, borne on a slender, downy stalk 1⁄2 to 1 in. long. Calyx edged with very minute teeth; petals oblong; stamens five to eight, sometimes more; seed-vessel somewhat cylindrical in shape.
Native of N. America, also of Greenland; introduced in 1763. A very hardy and pretty shrub, the commonest of the “ledums” in gardens and the most useful. It flowers from the end of April to June. From R. tomentosum (Ledum palustre) it is distinguished by its leaves being twice as wide. It has been said that it further differs in its fewer stamens (five to eight against seven to eleven in R. tomentosum), but according to Hulten (Fl. Alaska and Yukon (1948), p. 1219) this character is not reliable. It also varies to some extent in stature and shape of leaf.
R. groenlandicum and R. tomentosum inhabit moors and swampy districts in high northern latitudes and like a peaty soil or sandy loam free from lime. They can be propagated by seeds, treated as recommended for heaths, also by layers and cuttings.
Although the existence of hybrids between Ledum and Rhododendron has not been proved beyond doubt, there is in commerce a cultivar raised from R. trichotomum which most probably had a species of Ledum as pollen-parent. It has been named ‘Arctic Tern’. The generic name × Ledodendron was, however, published in reference to a putative hybrid between Ledum glandulosum and Rhododendron ‘Elizabeth’, the authenticity of which is doubtful (Barry Starling, The Plantsman, Vol. 4(2), pp. 97–9 (1982) and Vol. 5(3), p. 63 (1983)). [This nothogenus is now irrelevant JMG, June 2022}
Of dwarf habit, with short branches, very woolly stems, short broad leaves, and small flower clusters.