University of Vermont Extension
Department of Plant and Soil Science
Anytime News
Article
CHOICE PERENNIALS FOR 2010
Dr. Leonard Perry, Extension
Professor
University of Vermont
How do you decide what perennials
to choose from among the thousands available?
A good place to start might be those voted the top for this year of the
Perennial Plant Association, the industry group representing growers
and
professional garden designers, from which the perennial of the year
will be
selected. The top choices of perennial
professionals from across the country include relatively new cultivars
(cultivated
varieties) as well as a less known species.
'Northwind' is an ornamental
switchgrass (Panicum virgatum)
with bluish-green foliage, compared to
the green of the species or reddish of some cultivars. It is also
one
of the most upright of the
switchgrasses, many tending to flop over with age later in the
season.
The 4 to 5-foot clumps are topped, late in
the season, with one to 2-foot flowery plumes called "panicles" of
small yellowish flowers.
As with all switchgrasses it
prefers full sun and a moist and fertile soil.
It will tolerate sandy or clay soils, and drought once
established. It
is hardy to much of the north (USDA zone 4
or -20 to -30 degrees F average low in winter). This perennial looks
good in
masses, in the middle to back of borders, on slopes, and combined with
many
other perennials.
'Caramel' is one of the many new
coralbells (Heuchera), grown
mainly for its apricot leaves in light and
dark shades. It does flower in warm
areas with light pink small flowers on spikes above the foliage in
early
summer. This is one of the selections of
the hairy coralbells (H. villosa),
a southeastern U.S. native, although
it originated as a chance seedling in France.
Under good
conditions and warm climates it can reach 15 inches high and a bit
wider.
'Caramel' is listed as hardy to
USDA zone 4, with trials underway at the University of Vermont on the
hardiness
of this and other coralbells. It does
best in full sun in the north if kept watered, part shade in the
south. The best soil for it is a rich, moist loam
but well-drained. Try 'Caramel' in
masses in borders, under shrubs such as roses, along edges of beds and
paths,
and in containers. Contrast the leaf color
with that of darker blackish coralbells, or contrast the leaf texture
with ornamental
grasses.
The thread-leaf blue star (Amsonia
hubrichtii) is not hardy in all of the north (USDA zone 5 or -10
to -20
degrees F average winter low). Where it
does grow this less common perennial, native to the mountains of
Arkansas,
provides a mound of powdery blue, star-shaped flowers in early summer
in the
north. Plants form a mound 2 to 3 feet
tall and wide. It provides a fine
feathery texture with its thread-like leaves that turn gold in
fall.
Like other bluestars, this one
grows best in full sun in the north, and moist but well-drained soil.
It will
tolerate dry soil once established. Also
it will tolerate some shade, but may flop and have less showy fall
color. It is best massed in borders, by itself,
native plant gardens, or individually in rock gardens. It
combines
well with blue woodland phlox (Phlox
divaricata).
Recent Perennial Plant of the
Year winners that you might consider too include the golden Hakone
grass and
hellebores (both generally hardy to zone 5), 'Rozanne' perennial
geranium,
'Walker's Low' catmint, 'Becky' shasta daisy, 'David' garden phlox, and
Japanese painted fern. More on these,
and other winners, can be found online (www.perennialplant.org).
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