Archive | May 2015

Grow this: Japanese stewartia

Japanese stewartia (Stewartia pseudocamellia) is a beautiful four-season tree has graceful limbs and a dense, natural, pyramidal shape. Its bright green leaves giving way to orange to red to bronze-red fall color. The bark ranks as the best in the genus: mottled shades of brown, gray, and reddish brown. The flowers are white with bright yellow stamens and are quite showy in late May and June. Moist soils and Stewartia pseudocamelia flowerafternoon shade are preferred in the Carolinas. Other Asian and American species exist with outstanding qualities; however, they’re challenging to propagate and grow commercially. For an overview of cultivated species from a British perspective, along with Stewartia pseudocamelia treestunning photos, see the June 2008 issue of The Plantsman (“Stewartia in cultivation” by Eric Hsu, Timothy Boland, and Koen Camelbeke).


Gardenia: A can’t-live-without gem of the Southern lanscape

Gardenia August Beauty May 25 2015

August Beauty gardenia

I love gardenias.  Their perfectly sculpted waxy-white flowers and sweet fragrance are irresistible.  Native to China, Taiwan, and Japan, gardenias have been in North America for more than 250 years.  Named after Dr. Alexander Garden (1728-1791), a Scottish naturalist, physician, and planter, gardenias first arrived at Garden’s Yeshoe Plantation in Charleston (“Charles Towne”).  In short time, their popularity spread throughout the colonies and across to Europe.

Gardenias may reach a height and spread of 4 to 6 ft., although I’ve seen 8 ft. high specimens.  Their polished evergreen leaves provide an attractive canvas for their bountiful floral display, which is heaviest in late April to June and intermittent thereafter.

Heaven Scent gardenia  bloom

MADGA I (Heaven Scent®) gardenia flowers.

Since Dr. Garden’s time, gardenias have come a long way with so many delectable choices. Cultivars with double-white flowers include First Love®,  ‘August Beauty,’ and ‘Mystery.’ ‘Chuck Hayes’ bears jaw-dropping semi-double flowers, and ‘Grif’s Select,’ ‘Kleim’s Hardy,’ ‘Shooting Star,’ and ‘Variegata’ have single-white flowers. ‘MADGA I’ (Heaven Scent®) is a compact columnar-shaped gardenia with a height and spread of 3 to 4 ft.  It produces a blizzard of single white flowers in June and reblooms through August and September.  In the fall the flowers give rise to attractive orange-red fruits that persist in winter.
I’m especially enchanted by the double-flowered gardenias.  Often when I admire an exquisitely designed flower, time stands still—and for a brief moment everything seems right with the world.  Maybe that’s why gardenias have been cultivated for over a thousand years.

© 2015 Bob Polomski

In bloom: Crinums

Crinum_from Jenks to BPolomski

First flowers of Crinum bulbispermum.

Since moving to the South many years ago, I’ve always been fond of crinums (pronounced “CRY-nums”) or swamp lilies. In my travels across the state I’ve seen them in gardens, cemeteries, old home sites, and roadside ditches. In the spring bold green leaves sprout from underground bulbs (some attain the size of grapefruits) to create a fountainlike haystack of straplike leaves. In the summer clusters of lilylike flowers appear on three foot tall stalks in colors that range from white, pink, or striped (“milk and wine lilies”). Several common varieties include ‘Ellen Bosanquet’ (red), ‘Cecil Houdyshel’ (deep pink to red), and C. x powellii ‘Album (white). The Orange River lily (C. bulbispermum) is well-suited for wet areas (“hog wallows”); it’s flowering now in my garden (pictured) and will bloom sporadically though the summer and fall with white, pink or striped flowers.

Crinum Jenks to BP May 13 2015

Closeup of Crinum bulbispermum flower.

More hard-to-find cultivars worth seeking out include the purple-leaved ‘Sangria’ with deep wine-pink flowers and ‘Regina’s Disco Lounge’ with large pale pink-white flowers with a darker central stripe to each lobe. Depending on the cultivar, crinums may bloom one time or sporadically throughout the season. To see these and hundreds of other crinum species and hybrids, visit Riverbanks Garden in Columbia.

Crinums not only offer ornamental interest, but also provide functional uses as well. In a regional gardening magazine crinum purveyor/aficionado and South Carolina plantsman, Jenks Farmer, wrote how he used “Momma’s Orange River lily as a hurdle for running and jumping races.”

Beauty and durability: isn’t it time you added a crinum to your landscape?

In Bloom: Southern Magnolia

This native southern aristocrat has become a sensation over the past 30 years with the release of several cultivars that come in a variety of habits, sizes, and leaf shapes that make the species more suitable for smaller landscapes. Left to its own devices the moderately growing species becomes gargantuan (60-80 ft. high and 30-50 ft. wide). Select from the many available cultivars to acquire the right shape and density. The plastic-like leaves have a dark green waxy surface and green to fuzzy brown (indumentum) on the underside. The large 8 to 12 in. wide fragrant flowers appear in May. Flowers open sporadically in the crown and are often scattered; they do not open all at once like the deciduous magnolias. Many years are required to flower from seed (12 to 15), which is why you should select vegetatively propagated clones rather than sexually-derived ones.

The fruit is composed of follicles that occur in 3- to 5-inch long “cones.” The individual red seeds emerge as the cone matures. Once established this heat- and drought-tolerant species is well-suited for planting in groups, hedges, large screens, in streetscapes, and parks. Several exceptional cultivars include ‘Bracken’s Brown Beauty’, ‘Claudia Wannamaker’, ‘D.D. Blanchard,’ ‘Hasse’, ‘Kay Parris’ (introduced by Kevin Parris in 1993, it is believed to be the result of a cross between M.g. ‘Little Gem’ and ‘M. g. ‘Bracken’s Brown Beauty’), ‘Little Gem’, ‘Mgtig’ (Greenback®), ‘Southern Charm’ (Teddy Bear®), and ‘TMGH’ (Alta®). Brackens Brown Beauty M grandifloraBrackens Brown Beauty M Grandiflora flower

A small “flowering” tree to know and grow: flowering dogwood

Flowering dogwood (White dogwoodCornus florida)

Whether alone or in a group, flowering dogwood (Cornus florida) never disappoints me with its sublime springtime floral display. In late March to April the showy white “flowers” appear before the leaves unfold. These gorgeous, 3- to 4-inch wide showy white petal-like bracts lure me like the Sirens from Greek mythology. (A botanist will gleefully inform you that the “flowers” of flowering dogwood are not actually flowers, but bracts, which are modified leaves that look like petals; the true yellowish-green flowers are clustered in the center of these bracts).

These lovely floral bracts give rise to showy red berries in the fall. The fruit are complemented, if not upstaged, by the leaves that turn a stunning red to reddish-purple, which secures its place in the landscape as an essential spring and fall ornamental tree. However, I would arPinkdogwoodgue that the horizontal branches and flat-topped crown of flowering dogwood provide year-round interest.

Numerous flowering dogwood cultivars exist from whi
te to pink to red “flowered” forms. Although plagued by a few prominent insects and diseases (notably dogwood borer, dogwood canker anthracnose, and powdery mildew), there’s been a strong push at breeding disease-resistant dogwoods.

Site flowering dogwood in the right location:  partial shade (shade from afternoon sun) and the edge of woodlands. When growing in a relatively stress-free environment, this exceptional native American understory tree will captivate you year-round.

When to prune clematis? Depends on its group

Prune your clematis based on whether it flowers on last year’s wood, this year’s wood, or both. Experts divide the genus into three groups: Group I are all the early spring-flowering evergreen clematis and early- and mid-flowering species. This group includes Clematis alpinaC. armandiiC. macropetala, and C. montana. These clematis flower on last year’s wood and should be pruned after the flowers fade but no later than July. The only pruning really needed is to remove weak or dead stems and whatever is needed to confine the plant to its allotted space.

Group II consists of clematis that also flower on last year’s growth, but will produce a second flush of bloom on new growth. Here is included mid-season large-flowered cultivars such as ‘Bees Jubilee,’ C. ‘Henryi’, ‘Nelly Moser’, and ‘Vyvyan Pennell’.  Remove all dead and weak stems in late winter or early spring, and cut the remaining stems back to a pair of strong buds which will produce the first blooms. Occasional pinching after flowering will stimulate branching.

Group III consists of late-flowering cultivars and species that flower on this season’s growth such as C. flammulaC. integrifoliaC. x jackmaniiC. viticellaC. tanguticaC. texensis, and the herbaceous species. These can also be pruned in late winter or early spring. For the first two or three years they may be cut back to a foot from the ground. Later cut them back to two feet. If not cut regularly this group can become very leggy and overgrown.

The boundaries between these three groups are not absolute. Certain Group III clematis, for example, can be treated as Group II to produce early blooms on the previous year’s wood, but they serve as a rough guide to safely keeping your clematis vines within bounds.

Kousa dogwood in bloom now!

C kousa CL2 2015Similar to its distant cousin, flowering dogwood, the Chinese or Kousa dogwood (Cornus kousa) creates an uproarious floral display in late Spring. Despite flowering fashionably late after its leaves have completely unfolded, it’s still a spectacular sight to see the longlasting white four-pointed bracts of Kousa dogwood nestled comfortably above the leaves.

The flowers give rise to unique rosy-red fruits that look like raspberries on a stick; they are edible but insipid. Unlike the alligator-like bark of C. florida, the aging trunk of C. kousa exhibits beautiful flaking mottled bark patterns on a smooth trunk.

C kousa CL1 2015Kousa dogwood has better drought tolerance than flowering dogwood, and can be sited in full sun or partial shade.  Dogwood borers and foliar diseases rarely attack this species.

To capture the beauty and durability of both species, plant breeders have crossed kousa with flowering dogwood to create an exciting collection of hybrids touted for their insect and disease resistance. Recently, NC State Professor, Tom Ranney, created a hybrid between the pink-bracted Miss Satomi kousa dogwood and the evergreen Summer Passion Hong Kong dogwood (Cornus hongkongensis). The resulting offspring is called NCCH1 (Little Ruby™), a compact shrub or tree that bears four or more rose-pink bracts in late spring to early summer and burgundy-red fall color. NCCH1 has the added bonus of heat tolerance and disease resistance.

Bob Polomski, 2015 (R)