'Red Sentinel' Astilbe,
False Goat's Beard,
or False Spirea
"I found for you a scarlet blossom rare."
-Amy Levy
(1861-1889)
(1861-1889)
Variously called False Goat's Beard, False Spirea, Japanese Astilbe, Florest's Spirea or Featherflower, I prefer to just call it Astilbe. The cultivar 'Red Sentinel' is the reddest-flowering of astilbes, loose feathery panicles of scarlet florets on dark red stems. Even if planted among other red flowers, the intense scarlet of its blooms will stand out.
It was released in 1947 & has remained the most popular red since. It was bred by Van den Ouden in the Netherlands. Astilbe japonica hybrids are generally in the mid-sized range for astilbes. 'Red Sentinel's' foliage is usually only a foot & a half tall, two feet with the flowery plumes, but occasionally it can reach three feet in flower. Ideal for zones 6 through 8, it is stretchable to zones 5 through 9.
It flowers late spring & early summer, in a partial shade to dappled sunlight in moist well-draining humusy soil, or in full sun with a bit more moisture. Droughtiness with too much sun may cause partial die-back & tip-browning at the height of summer, but consistent moisture &/or a bit of shade usually keeps it fresh-looking even through hot spells.
Deadheading does not induce rebloom, so the fading plumes as they turn into seedheads can be left as long as they have any ornamental interest. When the dried seedheads are no longer attractive they can be removed so that the forest-green ferny foliage with mahogany stems can show itself to best effect.
For its first year in the ground it'll have only a couple plumes. As a clump matures it eventually spreads to a foot or foot & a half wide clump, providing a shocking intensity of many plumes. They can be planted close enough together to form a continuous groundcover, attractive in or out of bloom.
The plumes are usually loose & open so not as dense & feathery as on other cultivars. After three or four years it will be such a large clump it'll be crowding itself, & will need autumn or late-winter division to be refreshed.