November/December 2000
Issue
Gardener's
Notebook
2001 Perennial
Plant of the Year
The Perennial Plant Association (PPA)
has just announced that the 'Karl Foerster' cultivar of
feather reed grass (Calamagrostis 5acutiflora) is its
selection for the 2001 plant of the year. This popular
cultivar has long been prized for its ornamental
attractiveness, versatility, and minimal maintenance
requirements.
Hardy through USDA Zones 4 to 9 and
heat tolerant in AHS Zones 9 to 5, 'Karl Foerster' is an
erect, clump-forming grass suitable for sites in both full
sun and part shade. It thrives in moist, humus-rich soils,
but is tolerant of less favorable conditions. Plants form
clumps about two feet in diameter and spread slowly by
underground rhizomes.
The vertical growth habit includes a
tight clump of slightly arching foliage two to three feet
tall and flower stems to five or six feet in height topped
by airy panicles of pinkish bronze flowers in mid- to late
summer. These inflorescences gradually fade to pale brown
but often persist into winter.
To create a dramatic effect in the
landscape, the PPA recommends combining the cool-season
'Karl Foerster' with herbaceous perennials that bloom in
late summer and fall, such as fall asters (Aster spp.),
coneflowers (Echinacea spp.), gayfeathers (Liatris spp.),
and black-eyed Susans (Rudbeckia spp.).
'Karl Foerster' is widely available
through mail-order nurseries, including Kurt Bluemel, Inc.
in Baldwin, Maryland (www.bluemel.com,
800-248-7584), and Greer Gardens in Eugene, Oregon (www.greergardens.com,
800-548-0111).
EPA Says
Vermiculite Poses Little Health Risk to Gardeners
In August the U.S. Environmental
Protection Agency (EPA) announced the results of a study of
potential health risks associated with gardening uses of
vermiculite, a naturally occurring mineral long favored as a
soil additive.
The study concluded that although some
readily available horticultural vermiculite products were
contaminated with very low levels of asbestos, health risks
to home gardeners are negligible. The EPA warns, however,
that horticultural professionals who regularly work with
vermiculite products may face more serious health risks from
dust inhalation. Excessive breathing of dust of any kind can
cause respiratory illnesses, and inhalation of certain forms
of asbestos has been linked to serious lung diseases,
including cancer.
The EPA's investigation of
vermiculite, which started in January 2000, was prompted by
widespread public concern over possibly asbestos-tainted
vermiculite products. The public furor was set off by a
series of investigative articles in the Seattle
Post-Intelligencer relating to vermiculite produced from a
now-closed mine in Libby, Montana, that was found to be
contaminated with tremolite, a potentially hazardous form of
asbestos.
The EPA's testing was performed in two
phases. In the first, 16 products from Seattle area stores
were tested. Asbestos was detected in five, though only
three contained levels high enough to reliably quantify a
percentage. In the second phase, 38 vermiculite products
from around the country were tested. Asbestos was detected
in 17 of these products, but only five contained
quantifiable levels.
Since researchers reported a great
deal of variability in their results-often asbestos was
detected in one sample of a product, and not in another-the
EPA recommends that consumers take certain precautions when
using any pure vermiculite products. Among the agency's
recommendations are:
- Work with vermiculite products
outdoors or in a well-ventilated area
- Keep vermiculite damp during use to
reduce the amount of dust produced
- Avoid bringing dust into the home
on clothing
By taking such precautions, the EPA
says consumers can further reduce the already minimal health
risks associated with vermiculite's occasional use in home
gardening.
No precautions are suggested for use
of premixed potting soils that contain vermiculite-these are
usually slightly pre-moistened and contain a fairly low
percentage of vermiculite.
Possible alternatives to vermiculite
in home-made soil mixtures include coir (compressed coconut
fibers), peat moss, finely shredded bark, and perlite, but
gardeners should still avoid inhalation of dust that can be
generated from these alternative products.
"I agree that
the risk from using vermiculite is low," says
Carl Rosen, an Extension soil scientist at the University of
Minnesota in St. Paul. "The bottom
line is to make sure that the vermiculite is moist before
working with it to prevent dust inhalation," he
says. "I would recommend using a
face mask or respirator when working with any product-not
just vermiculite-that is dusty, to avoid unnecessary
inhalation of particles."
For further information on the EPA
vermiculite study, visit the agency's Web site at www.epa.gov/asbestos/.
