Good Things Growing 2.0, July 2010
by Fred Spicer, Executive Director
Aesculus parviflora, bottlebrush buckeye (left), is a handsome spreading, suckering, horizontally disposed deciduous shrub that grows at a slow to medium rate (faster from suckers), reaching 6-10’ in height and 8-15’ in width and more. The palmately (like fingers on your hand) compound leaves are reliably yellow in the fall. It is happiest – and flowers best – in part sun and average (not wet) soils. It has no significant insect or disease pests and is very drought-tolerant once established.
A strong-blooming stand of late bottlebrush buckeye
in a woodland clearing.
Clethra alnifolia, sweet pepperbush, is a suckering deciduous shrub that grows at a moderate rate to 6+’ tall by about half as wide. I have seen 12’ tall “colonies” in the northeast, but nothing close to that size in Alabama. Cultivars have been selected for pink flowers and compact size. Also known as summersweet, it requires some sun for good floral display and consistent moisture. Fall color is deep yellow. We have had mixed success with this species at The Gardens: after some initial success, the compact cultivars ‘Sweet Susie,’ ‘Sixteen Candles’ ‘Sotite’ (White DoveTM) and ‘Hummingbird’ all more or less succumbed to Alabama heat; the species (from an unknown provenance) has also performed poorly. None of the above except ‘Sweet Susie’ was planted in what I would term an optimal (regularly moist) location, so you may have better luck. ‘September Beauty’ has performed very well in a moist location, as has ‘Ruby Spice’ (with deep red buds and pink flowers); the latter has survived (not thrived) in a full sun, dry location. We have selections from the Florida panhandle and Coosa County, AL in propagation and are anxious to trial these ecotypes.
Rhododendron arborescens, smooth azalea, is a deciduous shrub with glossy leaves and variable (red and purple to yellow) fall color. Like all deciduous azaleas, growth is slow, but not maddeningly so, and it can reach 4-6’ tall and about as wide in 5-7 years, up to 15’ tall over time. Some sun is important for flower bud set and fall color to develop nicely; full sun is tolerated if the soil is moist and well-drained. This species is a mountain plant in the north, but closely follows stream corridors in the south.
There are a few other summer-blooming Alabama native woody plants worth mentioning.
The flowers of common buttonbush look like small satellites, bristling with antennae.
Cephalanthus occidentalis, common buttonbush (left) can continue its blooming cycle well into August. This shrub, with its Sputnik-like spheres of white, is another resident of swamps, lake and stream margins and other permanently wet areas. It has been recorded as occurring in almost every county in Alabama and ranges north into Maine, Minnesota and Canada; disjunct populations are found west into California (quite a large native range). The flowers are excellent butterfly fodder and the leaves are borne in whorls, one of very few plants with this leaf arrangement; most are either opposite or alternate.
Sambucus nigra subsp. canadensis [formerly S. canadensis], American black elderberry, is a shrub which flowers on wood of the current season (like the previous entry) and this trait means that flowers can be formed almost anytime during the growing season and will immediately open. Typically, the white, flat-topped cymes open through May and June in the greatest quantities and are only sporadic thereafter, on vigorous shoots of the most actively-growing plants. I have seen plants in Alabama with flowers in September. It also prefers damp places and the berries are known for making elderberry wine. To my tongue, they are not preferable to blueberries, but varieties have been named for large and prodigiously-produced fruit.
American wisteria flowers are more diminutive than their invasive Asian cousins’.
Wisteria frutescens, American wisteria (right), is the relatively well-mannered native relative of the Japanese and Chinese species that have escaped Southern gardens and have invaded roadsides and other disturbed areas. Differences that set it apart from its aggressive cousins are worth noting: smaller flowers (typically blue-purple), lighter fragrance, and relatively smaller stature (it still requires a strong support). It’s also a new-wood bloomer that spits out flowers consistently from (April) May through July, most heavily early in the season, but later flowers are very reliable.
I wrote about Rhododendron prunifolium, plum-leaf azalea (pictured below), two years ago in this issue, and raved that it was pretty much a lock to provide floral fireworks on the 4th of July here in Birmingham. That is true, but native populations share the anomalous later flowering tendency seen in southern populations of Rhododendron arborescens, sweet azalea, and can be in flower in early August.
Near Eufala, AL, this plumleaf azalea was flowering
in the last few days of July.