Horticulture: Extension: Gold Medal Plants

2008 Gold Medal Winners

Sweet William, Dianthus barbatus, was a popular plant in grandmother’s garden. Today, thanks to the introduction of the ‘Amazon’ series, this old-fashioned plant is making a dramatic comeback.

The Amazon series of dianthus resulted from crossing Sweet William, Dianthus barbatus, with Chinese pinks, Dianthus chinensis. The first introduction, called ‘Neon Duo,’ made its debut in 2002 and was an instant sensation among landscapers and home gardeners. It bears clusters of bright cherry red to purple flowers on the same plant and makes a dazzling statement wherever it is planted.

Following the success of Neon Duo, other introductions in the Amazon dianthus series soon followed, including Bouquet Purple, Neon Cherry, Neon Purple and Rose Magic. They are prized for their unique variations in flower color, often on the same plant. Rose Magic, for instance, bears a profusion of rose, pink, cherry and white hues within a single flower cluster. The flowers are sweetly fragrant, and they attract hummingbirds and butterflies.

The Amazon dianthus series are cool-season annuals, so it’s best to plant them in fall for winter and spring color. They make good companion plants for pansies, parsley, ornamental cabbage and ornamental kale. In some locations, the plants may live two years, but it’s best to grow them like annuals, so you won’t be disappointed if they don’t come back a second year.

Plants in the Amazon dianthus series have strong stems, easily reaching 24 inches in height, making them excellent for cut floral arrangements. They hold up in a vase for up to two weeks.

All the plants in the Amazon dianthus series prefer full sun and well-drained soil. Like other annuals, they benefit from organic matter, like compost, added to the planting area. Fertilize at planting, in late winter and again in spring with a granular fertilizer such as 10-10-10, 16-4-8 or 12-4-8. Apply the fertilizer when the foliage is dry, brush it off the flowers and foliage, then water it into the soil. If ground beds are not practical in your landscape, Amazon dianthus also adapt well to containers.

To ensure a continuous display of blooms and to maintain a neat appearance, pinch out and remove the old blooms when they fade.

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To most people, the words crane’s bill trigger thoughts of a long-legged bird with a long beak wading in a swamp. But to gardeners, cranesbill also refers to a type of hardy perennial geranium, prized for its toughness and long bloom period. The plant gets its name from the long, slender beak-like fruit produced after flowering. They look like a crane’s bill.

Today, cranesbill geraniums are among the hottest plants in the landscape industry, following the introduction of one called ‘Rozanne’ in 2001. Gardeners and landscapers throughout the southeast are singing the praises of this exciting new plant, calling is a “floral blockbuster” and an “exceptional performer,” even in the unrelenting summer heat and humidity of the southeast.

Rozanne Cranesbill Hardy Geranium is a patented hybrid introduced by Blooms of Bressingham in England. It was named for Rozanne Waterer who discovered it in her garden in Somerset, England, in 1990.

Rozanne Cranesbill Hardy Geranium grows in a well-rounded mound to a height of 18 to 20 inches. From late May until frost, the plant produces an abundance of blue-violet flowers with pale centers, approximately 2½ inches across. Attractive, deeply-lobed foliage turns brownish-red in fall and is quite showy.

Plant Rozanne Cranesbill Hardy Geranium in well-drained, amended soil and in full sun to lightly shaded sites. Fertilize at planting time with a complete granular fertilizer such as 10-10-10, 16-4-8 or 12-4-8, then repeat the application one or two additional times during the growing season.

This plant is a vigorous grower and is likely to decline in bloom during mid-summer when the sprawling foliage competes for the plant’s energy. At that time, a light shearing will encourage new growth and more flowers to brighten the fall landscape. After the first frost, cut back the plant and mulch it with leaves to provide a warm winter rest.

Use Rozanne Cranesbill Hardy Geranium in perennial borders, rock gardens or decorative containers.

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Gardeners are always searching for ways to disguise a fence, create privacy, cast shade over a patio, or add low-maintenance color to the landscape. Pride of Augusta Carolina Jessamine is an excellent choice for all these uses.

Pride of Augusta is a double-flowering form of our native Carolina Jessamine, the state flower of South Carolina. The bright yellow, tubular flowers are about 1 inch across and are borne in clusters along the stems. Bloom time varies from February to April, depending on geographic location and location within the landscape. Although the spring bloom is most dramatic, additional blossoms are produced sporadically throughout the growing season. Peak bloom lasts two to four weeks.

Also called ‘Plena’ in some catalogs, Pride of Augusta Carolina Jessamine is a twining, evergreen vine for sun or partial shade. It grows to a manageable 10 to 20 feet and is not invasive. Once established, it is low-maintenance, pest-free and deer resistant. Who could ask for anything more?

Like other Carolina Jessamines, Pride of Augusta needs help climbing a support, since it lacks the tendrils and holdfasts that other vines use to cling to a structure. Nylon fishing line wrapped around a post can be used to help guide the vine upward. As it climbs, the plant produces numerous shoots along its main stems, which week downward if left untrained. Occasionally, pruning may be necessary to thin these shoots and to direct the energy of the plant upward instead of outward.

Pride of Augusta Carolina Jessamine is a versatile vine. Not only does it adapt well to arbors, trellises and fences, it also can be used to cascade over large containers or walls. The bright yellow flowers contract particularly well with blues and whites.

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Follow your nose to Paperbush, Edgeworthia chrysantha, and it will be one of those “Gotta have it” plants for your landscape. Its heavenly scent blankets the mid-winter landscape and excites the senses, quickly drawing you to the source — clusters of creamy yellow flowers cascading downward from dark brown stems. You’ll want to touch the flowers to assure yourself they are real.

Paperbush is a deciduous shrub, growing 4 to 6 feet tall and 5 feet wide. Coarse-textured summer foliage is somewhat tropical in appearance, with leaves 4 to 6 inches long and 2 inches wide. They are bluish-green on top and silver-green below. As fall approaches, the older foliage gradually turns yellow and drops, then the remaining foliage sheds after the first real hard freeze, exposing the emerging flower buds.

The young flower buds are silvery in appearance, turning white as they expand, then creamy yellow when open. The flowers consist of dozens of tiny florets borne in clusters 1½ to 2 inches in diameter, suspended like bells on short stalks.

Smooth, chocolate-brown bark creates a striking contrast to the flowers and helps show them off. The dark-colored, leafless stems also add a dramatic silhouette to the winter landscape, particularly when they are backed by evergreens.

Paperbush prefers filtered shade and moist, well-drained soils to grow and perform well. It does not like drought or wet feet. Organic matter added to the planting area and mulch over the soil surface are recommended.

Plant Delights Nursery in Raleigh, North Carolina, is marketing the cultivar called ‘Snow Cream,’ which grows 6 feet tall and 6 feet wide and has larger leaves and flowers than the common Paperbush.

Paperbush is a plant for all seasons. Enjoy its showy, fragrant flowers and attractive bark from December to February and its bold, pest-free foliage from March to October.

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Adaptability to a wide variety of soils and growing situations is one of the criteria the Plant Selections Committee considers before elevating a plant to Gold Medal status. This criterian fits American Hornbeam, Carpinus caroliniana, to a T. This native tree grows from Nova Scotia to Florida and west to Texas, so it certainly has proven its adaptability over a wide range of climates and soil types.

American Hornbeam, in its native habitat, is most often found in rich, moist soils of the flood plains along rivers and streams, but it also adapts to dry upland sites. In the wild, it grows in the dense shade of taller trees, but it can adapt to full-sun sites. These characteristics make it a very versatile tree for a wide variety of landscape situations.

American Hornbeam is an excellent alternative to Bradford Pear, which has a problem with weak wood and limb breakage during storms. American Hornbeam has a broad, oval growth habit, similar to that of Bradford Pear, and reaches 30 to 40 feet high and 30 feet wide at maturity. Its dense foliage casts cooling shade in summer, then turns shades of yellow, orange or red in fall to brighten the autumn landscape.

American Hornbeam is sometimes called “Ironwood,” a name used to describe its very hard wood and dark-red to brown twigs. Early settlers valued the durability of the wood and used it for split-rail fences and fence posts. The tree is also called “Musclewood” due to its smooth, slate-gray bark that becomes ridged with age, looking must like rippling arm muscles of a well-conditioned athlete.

American Hornbeam bears separate male and female flowers on the same tree. In late summer, the female flowers become distinctive clusters of winged nutlets that hang down from the twigs on short stalks.

An interesting use for American Hornbeam, other than as a specimen tree, is to plant it as a hedge or screen plant and to shear it into a formal, box-like shape. Although this greatly increases the maintenance requirement of the plant, it adds an interesting, somewhat European, element to the landscape.

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