Azalea time

Plant people tend to mark their seasons not so much by the calendar date as what is flowering now, or just about to flower, especially with plants for which we feel special affection.

A plant that really marks the middle of springtime for me is the flowering of Western azalea, Rhododendron occidentale, a deciduous shrub that is frustrating to grow well in gardens, but which performs magnificently in the wild.

This shrub, generally about head height, dominates the margins of the all the lower creeks and seepages in The Cedars, in Sonoma County, California. For anyone new to this blog, a few words about The Cedars. It is a large area in NW Sonoma Co. composed entirely of serpentine rock called peridotite, most being a particular form called Harzburgite. Serpentine rock, and its derived soils, are hostile to most plant life, thus the plants that grow on serpentine areas tend to be unique or unusual. The Cedars is roughly about 7,000 acres of this rock, and is eroded into deep canyons with perennial water in the lower reaches. To view The Cedars on Google Earth, the approximate center is; 38(degrees)37'25.99"N and 123(degrees)07'02.86"W (sorry, I can't figure out how to insert a degree symbol in this program). Western azalea, while tolerant of serpentine soil with permanent water, is not restricted to this rock type. It can also be found along creeks and rivers in the Coast Ranges and Sierra Nevada, as well as coastal meadow/prairie. It is especially common in the mountains along creeks and in wet meadows. While the plant is surprisingly shade tolerant, it flowers most heavily when exposed to lots of sunlight - thus those at The Cedars, which often are out in full sun, can produce masses of flowers.

Western azalea in full sun on bank above creek.

At The Cedars the flower color is similar to that found in much of North Coastal California, that is, it varies from a relatively rich rose pink on some shrubs, to almost pure white on others, and most inbetween. All have a large golden or orange spot on the enlarged upper petal.

White flowered Western azalea.

Deep rose pink flowered; in all, the deepest color is on the reverse side.

The flowers produce a strong fragrance that most people find intoxicating, and inevitably the urge to bury your face in the glowing floral mass is impossible to resist. The fragrance is a rather heavy floral sweetness with hints of spice, and just a touch of skunkiness. The mefitic (skunky) component is due to the oily gland-tipped hairs that cover the outside of the flowers and young foliage. This gives Western azaleas a fragrance that is quite unique and memorable, while being highly enjoyable.

Although considered a gorgeous shrub, it has proven very difficult in cultivation; very slow growth, devastating powdery mildew in summer, and reluctance to flower being some of the common problems. In general, almost any plant seen in the wild looks better than the best-grown plant in cultivation, though of course, there are exceptions. The irony is that, especially in sites like The Cedars, the plants are growing exceptionally well, yet are growing in conditions that should be anathema for any self-respecting rhododendron. Here they grow in full all day sun with harsh reflected light and high heat, often in rock crevices devoid of any humus, no nutrients, and often with highly alkaline water - any one of these conditions enough to kill most azaleas or rhododendrons. Go figure!