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Rhododendron macrophyllum

Family: Ericaceae
Pronounced: roe-doe-DEN-dron mak-row-FIL-um


Geographic Origin:
Western half of Northern California to British Columbia.
Plant Group:
Sunset zones: No zones given.
USDA zones: 7-9.
Heat zones: 9-7.
Mature size:
Height: Up to 20 feet (6 m).
Width: 15 feet (4.5 m).
Flowering period:
May to June.
Flowering attributes:
Trusses with 15 to 20 funnel-shaped, pink flowers, open from rose-pink buds.
Leaf attributes:
Evergreen, dark green, 7-inch long, oblong leaves.
Full sun to partial shade.
Moist, but well-drained, humus rich, acidic soil.
Pruning Methods:
Prune lightly after flowering. Thinning and selective heading along with pruning crossed branches is all that is necessary. Rhododendrons usually wind up looking terrible when pruned for size reduction. If a rhododendron is outgrowing its designated area, dig it up and plant in a place where it can reach its glorious potential. Remove dead wood in summer when you can see it more easily.

Rainy Side Notes

In May, when our northwest native Rhododendron macrophyllum is in bloom, I love driving through Whidbey Island or around the Kitsap and Olympic Peninsulas, spotting the vast amount of this native species in full regalia. On a coastal trail near Florence, Oregon, I went for a hike just to see these rhododendrons in bloom along the coast.

Woodland edges light up with the this native shrub's pink flowers. Unfortunately, Scotch broom ( Cytisus scoparius), with its electric-orange flowers, sometimes blooms at the same time as the rhododendron's trusses of soft pink flowers open. The broom's color overpowers everything. If the pink flowers grow close, the garish orange flowers clash; growing further away, the rhododendron flowers fade into the woods.

Along a woodland edge where the rhododendrons grow with more sun, they reach about ten feet tall. In shadier conditions these beauties grow rangier and can reach up to 25 feet tall, looking more like a small tree than a shrub.

This Washington state flower is useful for many areas of the garden. Planted in woodlands under Douglas fir (Pseudotsuga menziesii) or western hemlock (Tsuga heterophylla), the shrub adapts well, even takes to growing in containers. Where deer are plentiful, this is a good choice, as they leave it alone.

Photographed in Florence, Oregon.

Rainy Side Gardeners —