TEN TOP TREES AND SHRUBS

Tantalizing choices for spring and beyond

byMICHAEL A. DIRR

AMELANCHIER ARBOREA,

DOWNY SERVICEBERRY; ALSO JUNEBERRY, SHADBUSH SERVICE-TREE

One of the finest native North American species for naturalizing the edge of woodlands. In the wild, it occurs along streams and on rocky slopes as a small tree or a large, multistemmed shrub of rounded outline. The emerging leaves are covered with numerous hairs, which impart an almost pussy-willow effect. Leaves mature to a rich green, one to three inches long, and in October they color yellow, orange, and apricot to dull, deep, rusty red. White flowers, in fleecy two- to four-inch-long racemes, appear slightly before or with leaves in April. In June, the 1/4- to 1/3-inch-diameter fruit mature like those of highbush blueberry (Vaccinium corymbosum) but are slighty sweeter, and they make outstanding pies. Birds are particularly fond of the fruit, so it is often a race between homeowner and feathered creature. With the annual rites of winter, the beautiful smooth, grayish streaked bark assumes center stage and provides an excellent effect. Downy serviceberry is adaptable to acid and high pH soils, and to moist or relatively dry situations. Many cultivars have been introduced, including several notable selections of the hybrid of Amelanchier arborea and A. laevis, A. xgrandiflora. Its cosmopolitan nature should endear this species to most gardeners. At home in Chicago, Boston, and Atlanta. Grows 15-25 feet high, variable spread; can grow to 40 feet. US-DA Zones 4-9. Maine to Iowa, south to northern Florida and Louisiana.

CALYCANTHUS FLORIDUS,

SWEETSHRUB, CAROLINA ALLSPICE

One of the great treasures of eastern North America, especially the open-grown specimens that develop into large, roundish shrubs and offer wonderfully fragrant, brown-maroon flowers in April and May. Truly an old-fashioned heirloom plant that I have found in many old gardens. It offers a sense of permanence and purpose. The lustrous dark green, two- to five-inch-long leaves turn a respectable yellow in autumn. Flowers appear on short stalks from the nodes of naked stems and continue to open as the leaves unfurl. The fragrance is reminiscent of a melange of ripening melons, strawberries, pineapples, and bananas. Unfortunately, seed-grown plants are unpredictable as to degree of fragrance, and some actually smell like vinegar.

Always buy the plant in flower to ensure pleasing fragrance. Site in any well-drained soil, in sun or partial shade. Although found in the wild on dry slopes as an understory plant, it performs more satisfactorily in good light. Great for the shrub border, and I have used it as a welcoming plant by the front door. Grows 6-10 feet high, 6-12 feet wide. Zones (4)5 to 9. Virginia to Florida.

Cultivars and varieties: ‘Athens’ (‘Katherine’) is a deliciously fragrant, yellow-flowered clone, with heavier-textured, dark green leaves that turn good golden yellow in autumn. ‘Edith Wilder’ offers the species’ flower color but with guaranteed floral fragrance. ‘Michael Lindsey’ produces deliciously fragrant maroon flowers and spinach-green leaves on a more compact framework.

CORNUS MAS,

CORNELIAN CHERRY

Few dogwoods are as durable as this underutilized yellow-flowered, red-fruited species. In the Midwest, it is the longest lived of all Cornus species. The habit is oval-rounded to rounded, with a dense network of rather fine stems. Used as a hedge, the branches grow so close-knit as to be impenetrable. The two- to four-inch-long, lustrous dark green leaves hold into late fall and may develop a semblance of purple-red fall color. Bright yellow flowers open on naked branches in March and are the only show in town. The 5/8-inch-long, ovoid, bright cherry-red fruit ripen in June and July. They serve as snacks for the birds or can be used for preserves and syrup. The species tolerates acid and high pH, as well as heavy clay soils, better than any dogwood. It usually suckers and develops large colonies, although some plants do not show this tendency. Grows 20-25 feet high, 15-20 feet wide. Zones 4-8. Central and southern Europe, western Asia.

Cultivars and varieties: ‘Aurea’ (yellow), ‘Elegantissima’ (green center, yellow border; pink shading on young leaves), and ‘Variegata’ (green center, white border) are the best available cultivars for colorful foliage. ‘Golden Glory’ is an upright form with abundant flowers, and it has proven its mettle in the Midwest, particularly in the Chicago area.

DIRCA PALUSTRIS,

LEATHERWOOD

A great, dapper, shade-loving native shrub that simply cannot find its way out of the shadows into commerce. This is a choice plant for those impossible shady garden areas; in fact, it performs more admirably in shade than in full sun, where the leaves bleach. The habit is oval to rounded, with light brown stems that are almost leathery. The egg-shaped, one- to three-inch-long, light green leaves are among the first to emerge in spring. In fall, they turn a clear yellow. Pale to bright yellow flowers occur on leafless stems in March and April and provide a barometer for spring. Fruit are 1/3-inch-long, oval, (reddish) green drupes that ripen in June and July. Provide organic-laden, moist, acid soil. Use in a woodland garden, in a naturalized situation, or in combination with ericaceous plants. Grows three to six feet high and wide. Zones 4-9. New Brunswick to Ontario, south to Florida and Missouri.

EDGEWORTHIA PAPYRIFERA,

PAPERBUSH

During our daily walks through the garden, my wife, Bonnie, and I always remark about the oversized, beautiful bluish green leaves that combine so seamlessly with the leaves and flowers of Hydrangea arborescens ‘Annabelle’. This unique plant is reserved for the shady nooks and crannies of the garden, where ample moisture is available. It is a suckering shrub, growing three to four feet high. The lithe, spotted, and stippled stems, lustrous red-brown with permanent light gray crescent-shaped leaf scars, are handsome in winter. The dark blue-green leaves are typically six inches long, although leaves from the plant in our garden measure 10 inches long. Flowers are unique, opening on naked stems in March and April, fragrant, silky white and yellow, in one- to two-inch-wide umbels. Flowers open over long periods, at least four to six weeks. Wonderful plant to combine with shade-tolerant broadleaf evergreens and wild-flowers. Becoming available in nursery commerce. Grows 3-4 (to 7) feet high, spreads by rhizomes. Zones 7-9. China.

Cultivars and varieties: ‘Grandiflora’ has large flowers and leaves; Edgeworthia chrysantha is bandied about as a larger-leaved species but looks like ‘Grandiflora’. ‘Jitsu Red’, ‘Red Dragon’, and ‘Rubra’—probably all the same—have reddish-tinted flowers.

LEUCOTHOE RACEMOSA,

SWEETBELLS LEUCOTHOE

What a beauty! Unfortunately, well known only by the native plant aficionados. Bonnie and I were hiking the Bartram Trail in Rabun County, Georgia, and spied a plant with elongated racemes and cylinder-shaped flowers. Had to key it out to be sure. A small, refined shrub that produces a suckering colony. The rich green, 1/2- to 2 1/2-inch-long leaves turn shades of red in autumn. The red-budded flowers are visible the year prior to flowering and are quite handsome in mid-April (Athens). The 1/3-inch-long white flowers open along the entire four-inch-long raceme. Definitely a woodland plant for moist soils. Grows 4-6 feet high. Zones 5-9. Massachusetts to Florida and Louisiana in moist to wet areas.

LINDERA BENZOIN,

SPICEBUSH

A most appropriately named shrub, because its bruised stems emit a potent, spicy-sweet odor. Imagine an early April day in the North after a particularly difficult winter, the branches of spicebush studded with small, greenish yellow flowers—a harbinger that all will be well in the world. To my mind, the species has never been utilized enough in American gardens. It develops into a large, multistemmed, rounded shrub, growing dense in sun, rather artistically open in shade. The three- to five-inch-long, bright green leaves turn a respectable to outstanding shade of yellow in fall. The oval, 1/3- to

PRUNUS CAMPANULATA,

BELL-FLOWERED OR TAIWAN CHERRY

The best flowering cherry for the Deep South, requiring minimal chilling hours to send its carmine-rose buds bursting forth. In the Dirr-garden, it typically flowers in late February and early March, complementing the witch hazels. In fact, the two make a pretty bouquet. Small, graceful, rounded in outline with spreading branches, it is among the most admired plants in our garden. Typical cherry leaves: glands on the petiole, margins set with fine, slightly incurved teeth, lustrous dark green, occasionally yellow-bronze-red in autumn. The carmine-rose flowers, 1 1/2 inches long, 3/4 inches wide, five-petaled, open along the naked branches. If untainted by freezing temperatures, flowers may be expected to provide three weeks or more of color. When the petals fall, the calyx tube, a ruby-rose color, is exposed and extends the overall effect. The fruit are red, 1/2 inch long, 3/8 inches wide, appearing almost rounded. Adaptable to sand and clay soil, preferably acid and well drained. Full sun to partial shade (pine) in coastal areas. Wonderful small garden tree. Should be in every gardener’s top ten where it can be grown successfully. Grows 20-30 feet high and wide. Zones 7-9, 10 on the West Coast. Taiwan, southern China, Ryukyu Islands of Japan

1/2-inch-long, bright red fruit ripen in September and October. The species is dioecious—fruit occur only on female plants. Provide acid, moist soils, in full sun to partial shade. Plants appear ragged in extremely dry soils. Fine choice for naturalizing, but unfortunately, it has never found its way into commerce. Grows 6-12 feet high and wide. Zones 4-9. Maine to Ontario and Kansas, south to Florida and Texas.

RIBES ODORATUM,

CLOVE CURRANT

A rare gem in the shrub world, this species offers wonderfully fragrant, golden yellow flowers in early to mid-April. The habit is upright-arching, usually prolifically suckering. The one- to three-inch-wide, three-to five-lobed, rich blue-green leaves turn yellowish to reddish in fall. The flowers have the fragrance of cloves. Quite adaptable to varied soils, in full sun or partial shade. Use in a shrub border or combine with bulbs and wildflowers. Grows 6-8 feet high, greater in spread. Zones 4-6(7). Minnesota and South Dakota south to Arkansas and Texas.

SPIRAEA THUNBERGII,

THUNBERG SPIREA

I take great delight in this wispy, fine-textured shrub. It offers light green, willow-like leaves, five-petaled, single, white flowers, and a bulldog’s tenacity that allows it to prosper in virtually any environment. The ultimate form is gracefully arching with a rounded-mounded outline. The yellowish green leaves are 1 to 1 1/2 inches long and 1/8 to 1/4 inches wide and turn orange and bronze in autumn. The 1/3- to 1/2-inch-diameter flowers appear on naked branches in March and April, well ahead of most flowering shrubs. Makes a great mass effect, or it can be used for color and textural purposes in the shrub border. Grows 3-5 feet high and wide. Zones 4-8. Japan, China.

HOW TO

PLANT A TREE

If planting a balled-and-burlapped tree, set the root ball in the hole and cut the cords that secure the wrapper. A real burlap wrapper may be rolled down, buried, and left to decompose. Nonbiodegradable synthetic wrappers must be removed. To do this, gently tip the root ball from side to side and slip the fabric out from under it.

  1. Measure the width and depth of the tree’s container or balled-and-burlapped root ball—a stake or a shovel handle are convenient devices for this. Then dig a saucer-shaped hole. It should be just deep enough to accommodate the roots of the tree and approximately three times as wide. Roughen the wall of the planting hole with a spading fork.

  2. If planting a container-grown tree, cut the side of the plastic pot with a sharp knife or heavy shears. Ease the root ball out of the container. With your knife, score the side of the root ball from top to bottom four times around the perimeter at equal intervals. Then stand the root ball in the planting hole, making sure that the top of the root ball is at the same level as the surrounding soil.

  3. If the soil excavated from the planting hole is compacted or poor, you may amend it with compost in an amount equal to no more than 25 percent of the whole. Otherwise, return the soil to the planting hole without amendment. Firm it in by treading lightly with the heel of your boot.

  4. Mound up soil into a three-inch-high berm around the perimeter of the planting hole. Fill the resulting well with water, let drain, and refill.

  5. To conserve moisture, spread two to three inches of an organic mulch over the entire root zone, leaving a clear area right around the trunk. (Covering the base of the trunk with mulch invites disease.) H

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