The tropics, grown against the odds. Sub-tropicals bring bold leaves, vivid flowers, and a whiff of the jungle to gardens well north of the frost line, thriving through a hot Southern summer and, with a little shelter, holding on through the cold.
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.
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.
The Rangpur is not truly a lime at all, but Indian gardeners have used the fruit as one for more than five hundred years. Citrus x limonia, an old natural hybrid of mandarin and citron, bears small, round, deep orange fruits that look like tangerines and taste fiercely sour, with the aromatic bite that makes a fine lime substitute for cooking, cocktails, and marmalade. In India the fruit goes by surkh nimboo, the red lime, prized for exactly that intense, tart juice.
Among the very first of the citranges, Citrus 'Rusk' dates to 1897, when Walter Swingle crossed a Ruby orange with the tough, cold-hardy trifoliate orange, Poncirus trifoliata, in the great effort to breed citrus that could take a freeze. The result is a vigorous, tall-growing, notably hardy tree, evergreen to semi-evergreen, and dense with the distinctive three-parted trifoliate leaves.
Named for Walter Tennyson Swingle, the pioneering citrus breeder who spent his career crossing tender oranges with the iron-hardy trifoliate orange, the Swingle citrumelo is among the toughest citrus hybrids ever raised. A cross of grapefruit, Citrus paradisi, and trifoliate orange, Poncirus trifoliata, this vigorous, thorny, semi-evergreen shrub or small tree carries fragrant white citrus blossoms in spring, followed by pear-shaped yellow fruits about the size of a large orange.
Woodlanders has long led in offering citrus and citrus hybrids hardy well beyond the usual citrus belt, and the Troyer citrange is a classic of the kind. A cross of the Washington navel orange and the inedible but iron-hardy trifoliate orange, Poncirus trifoliata, the Troyer was raised in 1909 under the direction of the great citrus breeder Walter Swingle, and later named for A. M. Troyer of Fairhope, Alabama, where the tree first bore fruit, a nice southern footnote for a hardy citrus.
Woodlanders has long led in offering citrus and citrus hybrids hardy well beyond the usual citrus belt, and U.S. 119 is one of the most refined of the group. A complex USDA hybrid, a citrumelo crossed back with a sweet orange, the tree runs one quarter trifoliate orange, one quarter grapefruit, and one half sweet orange, a pedigree chosen to keep the toughness of the trifoliate while pushing the fruit toward genuine quality.
US-942 began life as a rootstock, bred by the USDA and released in 2010 after years of Florida field trials, a careful cross of the Sunki mandarin and the curious Flying Dragon form of trifoliate orange, Poncirus trifoliata. As a rootstock the record is stellar: compact, productive trees, strong resistance to Phytophthora and tristeza virus, and better tolerance of citrus greening than most, which is why growers across the citrus belt have come to trust the number.
The sour orange is grown across the warm world as an ornamental and even a street tree, and stands somewhat naturalized in Florida. The fruit is famous for marmalade and useful little else, since the flesh is fiercely sour and bitter, not for eating out of hand. This particular unnamed selection has a Woodlanders story: we propagated the tree from a single specimen found growing on the edge of an abandoned sandy field in a remote corner of Appling County, Georgia, with no house anywhere near. What drew us was the crop, abundant, large, and very showy, loose-skinned and easy to peel.
Among the more intriguing fruits in the Woodlanders citrus collection, the Gou Tou sour orange stands apart, not only for rarity but for a rare combination of hardiness, heavy fruiting, and surprisingly pleasant flavor. Widely cultivated in Southeast Asia, Citrus aurantium 'Gou Tou' carries the form of a traditional bitter orange but with a taste that leans toward grapefruit, which makes this one of the most palatable sour oranges a gardener outside the subtropics can grow.
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.
Clerodendrum indicum, the Turk's turban, is a bold, tropical-looking perennial that stages two very different shows in a single season. First come tall, nearly unbranched stems, ringed with long narrow leaves and topped in summer by great airy sprays of long-tubed white flowers, shooting outward like a burst of fireworks, which earns the plant its other names, tube flower and skyrocket. Then, as the blooms fade, the real surprise arrives.
Clytostoma callistegioides is one of those vines that feels as though the plant wandered out of an old botanical expedition: vigorous, evergreen, and brimming with the sort of charm collectors once crossed oceans to find. A close relative of our native crossvine (Bignonia capreolata), this South American cousin shares the same athletic climbing spirit but dresses in glossier, more refined foliage and carries larger flowers.
Dianella tasmanica 'Variegata' is a strappy evergreen perennial grown above all for foliage: arching, sword-shaped leaves boldly striped in white and green that stay dense and upright through the season and lend crisp, year-round structure to a bed. In spring and early summer, airy panicles of small, star-shaped, blue to violet flowers rise on wiry stems above the leaves, followed by glossy, deep blue berries that gleam against the pale striping, an unusual and long-lasting ornamental touch that gives the plant a second season of interest.
Dicliptera suberecta is a member of the acanthus family, Acanthaceae, and hails from the grasslands of Uruguay and Argentina, a heritage that shows in a love of heat, sun, and lean soil. Gardeners know the plant by two names that between them tell the whole story: Uruguayan firecracker plant, for the volley of tubular blooms, and hummingbird plant, for the traffic those blooms draw.
