The shrubs that furnish a garden. Small and medium shrubs are the versatile, human-scaled woody plants that fill borders, edge paths, and knit the taller structure to the ground, the layer most gardens rely on most.
Native to Central and South America but naturalized across the tropics, this fast-growing shrub flowers not in spring or summer like a well-behaved plant but in autumn and into early winter, hanging great loose clusters of clear, saturated yellow at the ends of arching branches, each bloom built around curved stamens that give a vaguely butterfly-like silhouette. Cloudless Sulphur and Sleepy Orange butterflies find the shrub irresistible as both nectar source and larval host, and tend to arrive in numbers when the flowers open, a fact that either delights or mildly alarms a gardener, depending on how attached one is to the foliage. The caterpillars, for the record, are a vivid chartreuse and genuinely handsome. That is the bargain on offer.
'Buttercream' is a pale yellow-flowered form of Cassia bicapsularis, a softer, more refined take on that shrub's late-season show. Where the species blazes a saturated gold, 'Buttercream' carries clusters of cool, buttery cream-yellow flowers through autumn and into early winter, the same butterfly-like blooms at the ends of fast, arching branches, and the same draw for Cloudless Sulphur and Sleepy Orange butterflies that feed and breed on the plant.
September is a difficult month to write for. The garden is still technically in summer, but the light has shifted, lower and more golden, arriving at an angle that changes everything it touches. Cassia corymbosa reads that shift and answers it. While most summer shrubs are winding down, this one is only beginning, throwing dense corymbs of deep golden-yellow flowers at the branch tips with an enthusiasm that seems almost contrarian for the season.
Ceratostigma willmottianum, the Chinese plumbago, is a small deciduous subshrub grown for one of the truest blues in the garden. From midsummer into autumn the wiry, bristly-leaved stems carry clusters of intense cobalt-blue flowers, each a slim reddish-purple tube opening to five pale-blue lobes, and as the season cools the foliage turns a rich red and bronze, so that blue flower and crimson leaf often share the plant at once.
Cestrum elegans var. smithii is the soft, blush-rose form of the elegant cestrum, a fast, arching shrub that carries dense terminal clusters of slender tubular flowers in a warm pink, mildly fragrant in the evening and a steady draw for hummingbirds. Where the species runs to hot red-purple, this variety keeps things gentler, blooming from late spring well into fall, and year-round under glass.
Few plants announce themselves the way Cestrum nocturnum does, and never by daylight. Through the afternoon the shrub keeps to a quiet, almost ordinary green, the slender branches arching and half-climbing, the small tubular flowers furled and unremarkable. Then dusk arrives, the cream-green trumpets open, and the night-blooming jasmine releases a perfume so far-reaching that it carries across a whole garden on still, warm air.
Leatherleaf is the quiet constant of the northern bog. Chamaedaphne calyculata, the only species in the genus, is a low, thicket-forming evergreen of the heath family that ranges right around the cold northern world, from the peatlands of North America east to the bogs of Finland and Japan, and southward in this country to the pocosins and acid bogs of the coastal plain, as far as South Carolina. Across that vast range, leatherleaf forms the dense, spreading colonies that hold a bog together and shelter the wildlife within.
Choisya is a small genus of aromatic evergreen shrubs from the southwestern United States and Mexico, kin to citrus in the rue family, and Choisya 'Aztec Pearl' is the garden world's favorite of the tribe. The hybrid, a cross between Choisya arizonica and Choisya ternata, was raised by Peter Moore at Longstock Park Nursery in England, and the selection has proved hardier, more heat tolerant, and altogether easier in the garden than either parent.
The rockroses bloom as if for a single day, and in a sense they do. Each papery flower of Cistus x purpureus lasts only from morning to evening before dropping, yet through late spring the shrub opens fresh bloom after fresh bloom, so the whole plant seems perpetually covered. The flowers are the draw: two to three inches wide, crushed-silk petals of pinky purple, each stamped at the base with a deep maroon blotch, a marking that earned the old garden name orchidspot rockrose. Rockroses are not roses, and are not related; the resemblance is only in the open, five-petalled face.
The Yuzuquat is a tri-generic hybrid, a curiosity even among unusual citrus. One parent is the yuzu, itself a cross of Citrus ichangensis and Citrus reticulata; the other is the 'Nagami' kumquat, Fortunella margarita. From that three-way pedigree comes an attractive evergreen citrus that bears sour, juicy, lemon-like fruits about the size of a chicken egg.
NuClem is a special clementine among the cold-hardy citrus, a nucellar selection of the familiar clementine mandarin. Our friend and citrus guru Tom McClendon, who shared this one with us, explains it best: "NuClem is a nucellar Clementine, meaning that it comes true from seed. Most Clementines are polyembryonic, meaning that seeds will almost always produce hybrids with other citrus nearby. NuClem also is distinctive in its cold-hardiness, having proven reliably hardy in Montezuma, GA, making it probably on par with Satsuma. Fruit is globular, about two inches in diameter, with a mildly adherent peel more like an orange than a mandarin. Fruit quality is excellent."
The Meyer lemon is the great container citrus, beloved for thin-skinned, deep yellow-orange fruit that is sweeter and less acidic than a true lemon, and for fragrant, purple-tinged white flowers that come more than once a year. A small evergreen tree, the Meyer is thought to be a natural hybrid of lemon and some other citrus, probably a sweet orange or mandarin, which accounts for the mellow, almost floral flavor that has made the fruit a favorite of cooks.
Summersweet, or sweet pepperbush, is one of the most useful of the native shrubs for moist, shaded ground, and 'Hummingbird' is the compact, free-flowering selection that made the species a garden staple. Like the straight Clethra alnifolia, this is a stoloniferous deciduous shrub that forms colonies in moist, acid soil, valued above all for the upright spikes of intensely fragrant white flowers that perfume the whole garden in the heat of summer, when little else is blooming.
Clinopodium coccineum is a small, aromatic, semi-evergreen subshrub of the mint family, native to the deep, well-drained sands of the southeastern coastal plain, from Mississippi and Georgia down into Florida. The loose, open frame and small, spicy-scented leaves would earn a quiet place on their own, but the flowers are the event: showy scarlet tubes carried over a long summer season, held out like little trumpets that hummingbirds cannot resist.
'Amber Blush' is a soft-toned selection of the native scarlet calamint, Clinopodium coccineum, an aromatic, semi-evergreen subshrub of the mint family from the deep sands of the southeastern coastal plain. Where the wild species flowers in hot scarlet, this apricot clone brings a gentler, more complicated color to the same tough, hummingbird-loved plant.
Clinopodium coccineum 'Ohoopee Yellow' wears a contradictory name, since this is a clear, bright yellow-flowered form of a mint shrub that usually blooms in scarlet. The yellow form was originally shared with us by Ken Wurdak, who found the plant in Tattnall County, Georgia. We later lost our stock and got the clone back from Mike Creel, who had received starts from us years before. Such are plant sagas.
Colquhounia coccinea is a showy, soft-wooded shrub of the mint family, clothed in medium-sized leaves that are downy and pleasantly rough to the touch. Through late summer and fall come dense terminal spikes of orange-scarlet, yellow-throated flowers, a hot late-season color that hummingbirds and pollinating insects work eagerly. Plant in a sunny, well-drained site with good soil, where the arching stems can be trained against a warm wall.
The conradinas are dense, aromatic, low shrubs of the mint family, dressed in small, usually needle-like green or gray leaves and hung with little pale purple flowers. Six or seven species grow wild in the southern United States, most of them in Florida on sand or very sandy soil, and all but this one (and one possibly new species) are federally listed as threatened or endangered. Conradina canescens is the common, widespread member of the clan, a somewhat variable plant of the Gulf Coast dunes of northwest Florida and adjacent Alabama.
Some years ago we introduced two selections of Conradina collected on the Styx River in southern Alabama, called 'Low Gray' and 'Low Green', and we hope those clones survive in cultivation somewhere still. On a return visit to the Styx River site we gathered several more cuttings from distinctly low-growing plants. This conradina haunts a sandy woodland and cutover near the Styx River, and may well represent a new, as yet undescribed species; what appears to be the same plant turns up some miles east on Blackwater State Forest in northwest Florida. The Styx River plant differs clearly from the taller, more upright Conradina canescens of the open Gulf Coast.
A small shrub of the Cumberland Plateau, found only on the flood-scoured cobble and sand bars of three river systems in eastern Tennessee and a sliver of Kentucky: the Big South Fork of the Cumberland, the Caney Fork, and the Obed. The rest of the Conradina clan keeps to the sand scrub of Florida and the Gulf Coast of Alabama, sun-baked and semitropical. This species took a different path, north into the cooler uplands, and the cold-hardiness that came with the move is the gift to gardens farther north.
