"Native plant has become a buzzword in horticultural circles," Castorani says, "and I'm all in favor of their use, but as horticultural professionals, we have a long way to go in helping the home gardener understand their value."
For landscape professionals, horticulturists and homeowners, this conference will provide two days of fascinating sessions. Comprehensive conference registration is $135. For more information and a brochure, write to Native Plant Conference, Department of Continuing Education, 104 Dilworth Hall, Millersville University, Millersville, Pa. 17551.
From a broad perspective, native plants are of value to landscapers for large sites and to homeowners for their own gardens because, unlike exotic introductions, they are well-adapted to local situations. Unfortunately, Castorani says, horticulturists sometimes fail to point out to customers that even these plants have specific needs:
"A classic example is the homeowner who wants to develop a woodland wildflower area. It sounds simple; conditions should be perfect because the site is shaded. On inspection, however, we find the conditions are far from perfect because the builder has removed a deep layer of topsoil, a key ingredient for the successful growth of woodland plants."
Castorani sees the native-plant business from both sides - as president of his own landscaping company and co-owner with C. Dale Hendricks of North Creek Nursery, a wholesale company in southern Chester County devoted to the production of plants for naturalistic landscaping.
North Creek produces a wide array of plants "with a great emphasis on those native to the Eastern United States," says Castorani. "All plants are propagated here at our nursery. No plants offered are collected from the wild."
Castorani and Hendricks are continually searching for species and varieties of native plants suited to home and commercial landscaping. In some cases, they make the selections. Hendricks, for instance, found Heuchera americana Dale's Strain in the woods of North Carolina. A horticultural colleague named it for Hendricks, and now it's caught on in the trade as an excellent ground cover for dry areas in sun to shade, with silver-blue marbled foliage.
North Creek Nursery includes a broad offering of asters, including Aster nova-angliae Purple Dome, an introduction from the Mount Cuba Center for the Study of Piedmont Flora in Greenville, Del. Unlike many asters, Purple Dome is compact, maturing around 18 inches, with deep purple flowers. Castorani
recommends planting this in combination with Stella D'Oro, that low-growing tough day lily, or other yellow-blooming perennials. It's also excellent as a container plant and is sold in the fall as an alternative to chrysanthemums.
Solidago sphacelata Golden Fleece is another Mount Cuba introduction, and Castorani highly recommends this goldenrod as an excellent ground cover in full sun or part shade. The yellow blooms will be evident from mid-August to October, and the plant is only 18 inches high.
For full sun where you can use a tall plant, Castorani and Hendricks suggest Rudbeckia maxima. Native to landscapes farther south but hardy through Zone 6, this daisy has greenish/blue foliage and large golden coneflowers in June and July. For maximum development, plant in deep moist soil, and you'll see the plants grow 6 to 7 feet tall.
North Creek also carries a small selection of woody plants. Many are natives, including Virginia sweet spire (Itea virginica Henry's Garnet), a winner of the Pennsylvania Horticultural Society's Gold Medal Award in 1988. Tough and adaptable, Henry's Garnet will grow in a variety of soil conditions,
from dry to damp.
To most of us, honeysuckle is a noxious weed, creeping over woodland and edge plantings. "That weed," says Castorani, "is the Japanese honeysuckle, but there's a native, non-invasive alternative, Lonicera sempervirens Cedar Lane." It has deep red flowers in May and June and is a "real magnet" for hummingbirds.
WHAT TO DO THIS WEEK
For fall crops of broccoli, cabbage and cauliflower, or for extended crops of tomatoes, sow seeds inside or in a seedbed outside before mid-June.
June is a good month to work on those hedges. As you prune, remember to keep them narrower on top than at the base so the lower foliage will get light and remain healthy.