Tree Talk: Rhododendron’s act three and finale


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There’s probably no flowering plant that is more cherished in the Pacific Northwest, more representative of our exuberant horticultural scene, than the Rhododendron.

Mother’s Day in May is considered the peak of the season for these flamboyant bloomers… and it is. Especially so, for the named hybrids that most nurseries offer and most of us grow. Yet, the sagacious gardener knows that what they are seeing in the month of May is no more than a show stopping number in the middle of the performance. Any number of Rhododendrons have been blooming since early Spring and others will be going well into June. 

If you want to stretch the Rhododendron season over a four month period, start looking for plants to make that happen. There are plenty. Rhododendron strigillosum, opens its large deep red flowers sometimes as early as mid February. Look around, visit public gardens, talk to nursery people. Specialty nurseries often begin marketing flowering Rhodys in March. Make a trip to the Rhododendron Species Botanical Garden (2525 S. 336th St, in Federal Way). This is the World’s largest collection of Rhododendron species (the plants as they appear in nature, before hybridizers have cross pollinated them). Catalogs and websites often list Rhododendrons as Early, Mid or Late Season.

June flowering Rhododendrons are as surprisingly abundant as the early bloomers and there are flower hues that will fit into any carefully orchestrated garden color scheme. Rhododendron ‘Evening Embers’ is vibrant red, R. ‘Scintillation’ is deep pink, R. Daphnoides’ is purple, R. ‘Goldflimmer’ is rosy pink. 

In a class by itself is Washington’s state flower, the native Rhododendron macrophyllum. It will be filling our forests with its pink to pale lavender blossoms this month, most vividly along Hood Canal and on the Olympic Peninsula. Selected to represent the state in the floral exhibit at the 1893 Chicago World’s Fair, this beloved  native was designated the state flower by our legislature in 1959. 

Our native Rhododendrons are statuesque plants, a bit more loose and open than the hybrids we are accustomed to, but in a shady location, at the edge of the garden, they will stretch up and out, gracefully, to a height of 15 feet. Rhododendron macrophyllum  is an exquisite plant all year around. It is especially effective paired with ferns and other woodland ground covers. 

Most Rhododendrons flourish in light shade. They love our rich, loamy acid soil. You can put them in the ground any time, but it is important to keep them well watered albeit with ample drainage. In truth they are an easy plant to grow here. So while you may have enjoyed the big production number at the end of Act Two last month, the show ain’t over! Start thinking about a riveting Act Three for your garden with a zinger of a finale.