catnip (Nepeta cataria)
SCIENTIFIC SYNONYMS: There are no scientific synonyms for
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of catnip is Nepeta
cataria L. Catnip is a fairly typical example of the Mint Family of plants.
While this plant is occasionally cultivated in residential areas, it escapes
readily and is more often found in the wild. Catnip is fairly easy to identify,
in part because of its distinctive aroma, which is not entirely pleasant to
humans. Perhaps the most distinctive feature of catnip is the appearance
of the dense whorls of flowers on the spike-like racemes. These whorls of
flowers are crowded closely together and are rather sloppy in appearance.
Other members of the Mint Family usually produce axillary whorls of
flowers above the opposite leaves, or they produce terminal spike-like
racemes that are more slender or interrupted. The flowers of Stachys spp.
(Hedge Nettles), another genus in the Mint Family, have an upper lip that
is more similar in size to the lower lip, whereas in catnip the upper lip of
the flower is substantially smaller than the lower lip. Another common
member of the Mint Family, Teucrium canadense (American germander),
has an upper lip on its flowers that is even more reduced in size than catnip's.
Whereas some members of the Mint Family have foliage that is coarsely
hairy or devoid of hairs, the foliage of catnip is finely pubescent (canescent).
Furthermore, the leaves of catnip are cordate at the base, rather than
wedge-shaped or rounded.
NATIVE STATUS: Introduced, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This introduced perennial plant is 1-4' tall, branching occasionally.
The light green stems are finely pubescent and 4-angled.
Leaves: The opposite leaves are up to 4" long and 2" across. In shape, they
are cordate with blunt tips or ovate with a cordate base. Their margins have
large crenate teeth. The upper surface of the leaves is canescent (very finely pubescent) and a reticulated network of veins is clearly visible. Their peti-
oles are about 1" long, finely pubescent, and 4-angled.
Flowers: The upper stems terminate in dense whorls of flowers on spike-
like racemes about 1-6" long. Each flower is about 1/3–1/2" long. The
corolla is tubular, 2-lipped, and usually dull white; on rare occasions, it is
light blue-violet. The upper lip is small and consists of 2 rounded lobes,
while the lower lip is large and has 3 lobes. The middle lobe of the lower
lip is the largest with a frilly outer edge, while the 2 side lobes are much
smaller. Usually the lower lip of the corolla has small pink or purple dots.
There are 4 stamens with anthers that are about the same length as the
upper lip, to which they are adjacent. The tubular calyx is light green and
finely pubescent. It has 15 nerves along its length and 5 triangular teeth.
The flowers don't have a noticeable fragrance, although the foliage has a
pungent aroma that resembles a combination of thyme and oregano.
Fruit/Seeds: Each flower is replaced by a seed capsule containing 4 oval
nutlets. Each nutlet has a smooth curved surface that is lacking in sharp
Roots: The root system consists of a taproot and produces abundant rhi-
zomes. This plant often produces vegetative colonies.
REGENERATION PROCESS: Catnip propogates itself by reseeding
and vegetative production through rhizomes.
HABITAT TYPES: Habitats include limestone barrens on bluffs, open
woodlands, weedy meadows, pastures, fence rows, gravelly areas along
railroads, and miscellaneous waste areas. Sometimes this plant is cultivat-
ed in herbal gardens. It is usually found in disturbed areas, but occasional-
ly invades natural areas where limestone is close to the soil surface. This
species was introduced from Eurasia.
SITE CHARACTERISTICS: This is an adaptable plant that typically
grows in full or partial sun, moist to dry conditions, and a soil that is loamy,
rocky, or gravelly. Limey soil with a higher than average pH is preferred,
but it will grow in ordinary garden soil. The mature size of this plant is
strongly influenced by moisture levels and soil fertility. It's more drought
resistant than many other members of the Mint Family.
SEASONAL DEVELOPMENT: The blooming period occurs during the
summer or early fall (June to September), and lasts about 1-2 months.
GENERAL DISTRIBUTION: Catnip is found throughout the conti-
nental United States (with the possible exception of Florida) and all
the southern Canadian provinces (it does not naturally occur in the
northern territories of Canada).
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: The nectar of the flowers attracts long-
tongued bees primarily, including honeybees, bumblebees, cuckoo bees
(Epeoline), and miner bees. Other visitors that occasionally visit the
flowers include Halictid bees, wasps, flies, butterflies, and skippers. The
foliage is one of the food sources for the caterpillars of Sphinx eremitus
(Hermit Sphinx). Sometimes the caterpillars of Pyrausta spp. (Pyralid
Moth spp.) feed on the foliage as well. The pungent foliage is shunned
by mammalian herbivores as a food source. One animal that is strongly
attracted to catnip, however, is the domesticated house cat. Apparently,
a chemical in the foliage produces a pleasant intoxicating effect in cats,
somewhat akin to the effect of marijuana on humans. As a result, plants
in residential areas may display signs of damage from cats rolling in the
Catnip is well known to be of great interest to many domestic cats, although
the compounds arousing cats presumably evolved as deterrents against
insect herbivores and interactions between catnip and cats are presumably
not of ecological or evolutionary significance. Researchers have found that
cats respond to catnip with predictable behaviors, including (1) sniffing, (2)
licking and chewing with head shaking, (3) chin and cheek rubbing, and (4)
head-over rolling and body rubbing. They may also exhibit digging or paw-
ing, scratching, salivating, washing or grooming. stretching, animated leap-
ing, licking of the genital region, apparent hallucinations, sexual stimula-
tion, euphoria, sleepiness, and/or eating. The complete response rarely ex-
ceeds 10 to 15 minutes and is followed by a refractory period of about an
hour during which catnip does not elicit a behavioral response. Interesting-
ly, no response to catnip is evident in kittens during the first 6 to 8 weeks
after birth, and this response may not develop until 3 months of age.
Not all domestic cats respond to catnip. Based on a study using a docu-
mented pedigree of Siamese cats and a random sample of 84 cats from
the Boston area, it was concluded that the catnip response is inherited
as an autosomal dominant gene. Investigations of a variety of mammals
have revealed no catnip response in non-felids tested, but within the
Felidae (Cats) many (though apparently not all) wild cat species, both
males and females, exhibit a catnip response. The physiologically active
component of catnip oil is a now well-characterized compound known as
Dried leaves and flowering tops are used medicinally as a stimulant, tonic,
carminative, diaphoretic, and for infantile colic.
Crooked Run Valley