Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, November 24, 1994 TAG: 9411280003
SECTION: CURRENT PAGE: NRV-8 EDITION: HOLIDAY
SOURCE: JOE HUNNINGS
DATELINE: LENGTH: Medium
For the most part, however, consumers don't know much about tree and shrub pests, and some growers tend to plant whatever sells. Thus our landscapes contain many plants that require extensive management and excessive pesticide applications, but still die prematurely.
Recently, Richard Casagrandes, an entomologist from the University of Rhode Island, described coming across a Rhode Island bed and breakfast that was installing a new hedge at considerable expense. The inn's owners planted about 75 Canadian hemlocks and three flowering dogwoods at an estimated cost of $6,700, not counting labor.
The property owners can now look forward to annually applying insecticides against the hemlock wooly adelgid, which is now killing their neighbor's hemlocks. (This pest is wreaking havoc with hemlocks in the New River Valley as well.) They'll also need up to three annual fungicide sprayings on the dogwoods to control anthracnose disease. With diligent care, these trees mature to a size where they are too large and too costly to spray. They will die later, rather than sooner, with a substantial cost to remove and replace them.
These problems could have been avoided. The hedge could have been planted with Japanese or western hemlocks. The dogwoods could have been Cornus kousa or Stellar series hybrids. For roughly the same cost, the inn's owners could have used plants that withstand pests. In the long run, it would have saved them hundreds of dollars in annual pesticide costs.
With support from growers and the Northeast Region "Agriculture in Concert With the Environment" program, Casagrandes' team is helping landscapers, homeowners and nursery producers discover and use plants that require less water, fertilizer and pesticides. The project's goal is to get everyone working from the same menu - a list of sustainable trees and shrubs.
The list is the key element in their program, but the project also involves the development of a logo, a point-of-sale tag, a manual, and demonstration landscapes - all intended to further the use of sustainable plants.
The list describes approximately 200 useful landscape plants that, to their knowledge, are non-invasive and require less water, pesticides and maintenance. It also lists 128 common landscape plants that are more trouble-prone, and the major problems that eliminated these plants from the sustainable list.
Development of the list has been a cooperative venture involving the Rhode Island Nurserymen's Association and faculty from the University of Rhode Island and the University of Massachusetts. It has been reviewed by two dozen leading experts in the region, including nursery producers, landscapers, arboretum managers and faculty.
How did they gauge the "sustainability" of various plants? Primarily through observation and experience. They found that a number of the plants on the list contain chemicals that seem to confer protection against insects and pathogens. For other plants, physical characteristics - such as hairy or waxy leaves - provide protection.
These plants are on display at a demonstration site, the "Learning Landscape," surrounding the University of Rhode Island Cooperative Extension Center. This 1.5-acre landscape, designed and managed by the Cooperative Extension Center, received a large boost from the Rhode Island Nurserymen's Association, which provided the plant materials and labor (a donation of approximately $100,000) for the project. Trees and shrubs were selected from the sustainable list, demonstrating many excellent plants less familiar to the trade.
Despite the fact that Virginia Cooperative Extension does not have a specific sustainable tree and shrub list, county extension offices can help you make proper plant selections. Perhaps a formal list can be produced in the future.
In the meantime, be sure to visit public gardens such as the Virginia Tech horticulture gardens. This beautiful landscape, maintained under the direction of Robert Lyons of the horticulture department, has developed into an excellent learning laboratory. There are many different trees, shrubs, grasses and ground covers to view in addition to the highly popular herbaceous annuals. Visit, take notes and ask questions of your extension agents and area nurseryman. You'll be well on your way toward establishing a stress-free garden of your own.
Joe Hunnings is the Virginia Cooperative Extension agent for agriculture in the Montgomery County Extension Office in Christiansburg. If you have questions, call him at 382-5790.
by CNB