University of Vermont Extension
Department of Plant and Soil Science
Dr. Leonard Perry, Extension Professor
University of Vermont
There are many colorful catmints to
choose for gardens, some more attractive to cats than others. These plants
provide easy culture, many flowers in cool blue and lavender colors, a long
season of bloom, and attractive leaves.
As the name indicates, this genus of
perennials (Nepeta) is in the mint
family along with such relatives as the giant hyssop (Agastache), bee balm (Monarda),
and lamb’s ears (Stachys). In addition to mint, many herbs also are in
this family including lavender, rosemary, and thyme. All share traits of two-lipped flowers,
square stems, opposite leaves, and often fragrant oils.
It is the oil “nepetalactone” which
causes various behaviors in cats, depending on the cultivar (cultivated
variety), the cat, and its use. Rubbing
leaves releases vapors that produce a short-lived high in cats, while eating
leaves can make them sleepy. The true
catmint (N. cataria) is the most
intoxicating to felines.
Catmints are best grown in full sun
and well-drained soils. Once
established, some are drought tolerant.
One species is an exception (N.
subsessilis), being adapted to part shade and moist soils. Their main problem is wet soils which cause
poor health, and too much fertilizer which causes floppy stems. If plants become unattractive after bloom,
shear back by about two-thirds
to promote new lush growth. Cutting back
taller cultivars by about one half in early summer may delay flowering
somewhat, but will promote lower and more bushy growth.
Depending on selection, catmints can
be used in borders, herb gardens, rock gardens, massed, as edging, or as
groundcovers. A great place to use them
is to soften edges of paved surfaces such as walks. Their lavender to blue flowers combine well
with yarrows, hardy geraniums, sages, ornamental grasses, black-eyed Susan,
coneflowers, and Shasta daisies. They
are good for pollinators such as bees, butterflies, and hummingbirds.
A study at the Chicago
Botanic Garden, similar in climate to
much of central New England (USDA zone 5b),
compared over 30 selections of catmint for at least four years each. Four rated best for vigor, flowering,
hardiness, and freedom from problems.
These didn’t need shearing to rejuvenate.
‘Joanna Reed’ blooms from mid May to
late October in Chicago,
with lavender-blue flowers. New growth
of dusty green leaves quickly hides the declining flower stems. It forms a tidy mound 24 inches high and 48
inches wide. Similar, only slight
higher, was another top rated cultivar ‘Six Hills Giant’. This one has been around for many years and
is commonly found.
‘Select Blue’ (N. x faassenii) is similar
to the first two above, only shorter (14 inches) and less tall (30
inches). It has a shorter bloom period,
but still quite long in Chicago
from late May to mid September. The
flowers are a bit darker than the species, but still lavender.
‘Walker’s Low’ (N. racemosa) was the other top rated catmint, and is not low as its
name implies. Instead, it is named for a
garden in Ireland. Its height is similar to ‘Six Hills
Giant’. It bloomed in Chicago from mid May to late September. This cultivar also holds the honor of being
the 2007 Perennial Plant of the Year of the Perennial Plant Association.
If you can’t find these four
selections, don’t worry as 22 of the 30 catmints in this trial rated highly.
One of these is the popular ‘Souvenir d’Andre Chaudron’ (N. sibirica). This large
plant, reaching three feet wide and high, benefits from pruning back in early
summer. While the top four rated
selections all had dusty or gray-green leaves, this one has green leaves. It has a long, but shorter, bloom period more
just during summer.
For pink flowers, look for the
cultivar ‘Sweet Dreams’ (N. subsessilis),
or ‘Dawn to Dusk’ (N. grandiflora)
for pale pink flowers.
Full details on the catmints, and other
perennials, at the Chicago Botanic Gardens trials can be found online
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