Rhododendron x 'Koromo Shikibu'

'Koromo Shikibu' is the spider azalea, and there is nothing else in the genus quite like the flower. Instead of the usual funnel, each bloom splits into narrow, strap-like petals that spread apart like the legs of a starfish or a spider, lavender to purplish-pink, spotted darker at the base, and carried in such profusion in spring that the whole shrub seems to shimmer. Once seen, the flower is not forgotten.

The plant is Japanese, and the exact parentage is a small mystery: often sold as a Kurume azalea, this azalea is more likely a hybrid or form of Rhododendron macrosepalum, the species that carries the spidery, split-petaled trait. The name 'Koromo Shikibu' is usually translated as a court lady's robe, koromo meaning a garment and Shikibu an old court title, though the reference is more poetic than documented. Whatever the pedigree, the American Rhododendron Society thought enough of the plant to name it Azalea of the Year in 2015.

Beyond the flowers, this is a well-behaved evergreen azalea, upright and slowly spreading to three or four feet, clothed in small, hairy leaves that take on a bronze cast through the winter. As an evergreen azalea, this one is less cold-hardy than the native deciduous kinds, best from USDA zones 7 to 9 and worth a sheltered spot at the cold edge, where hard winters may thin the foliage. Give part to full shade, moist but well-drained acidic soil, and steady water.

One honest caution comes with all the azaleas: every part of the plant carries grayanotoxins and is poisonous if eaten, so keep the shrub away from where children or livestock might browse it. Set 'Koromo Shikibu' as a specimen in a shade or woodland garden, in a mass on a shaded slope, or anywhere the strange, strappy flowers will draw a second look, and enjoy a spring show that stops visitors mid-path to ask what on earth it is.