This is a shrub about 1-3½' tall that has ascending to
branches. The bark of branches and twigs is gray or reddish brown, more
or less smooth, and terete with scattered white lenticels. Young shoots
are light green to light brown, terete, and very pubescent, becoming
less pubescent with age. Alternate leaves occur along the twigs and
These leaves are 2-6" long and ¼-1" across; they are narrowly oblong to
oblong-elliptic in shape and pinnatifid with 3-8 pairs of oblique
lobes. The upper surface of mature leaves is medium green and glabrous
to slightly short-pubescent, while the lower surface is light green and
nearly glabrous to short-pubescent. Immature leaves, in contrast to the
mature leaves, are yellowish green and more heavily covered with silky
hairs (especially along their undersides). The leaves also have
glandular resin-dots; crushed leaves and twigs are fragrant. The
petioles are less than ½" in length, light green, more or less
pubescent, and relatively stout.
Sweet Fern can be dioecious or monoecious
with unisexual florets that are arranged in greenish catkins toward the
tips of twigs or young shoots. The male catkins are ¾-1½" long and
cylindrical in shape, consisting of numerous male florets and their
overlapping scales. Each male floret has 4-8 stamens on short
filaments; it is partially hidden by a small scale (about 2-3 mm. in
length) that is broadly ovate and ciliate along its margins. The female
catkins are about ½" long and ovoid to globoid in shape, consisting of
a small cluster of female florets and their scales. Each female floret
has a naked ovary with a pair of stigmata at its apex; it is partially
hidden by a
small scale (about 2-3 mm. in length) that is broadly ovate and ciliate
along its margins. In addition to this scale, there is a pair of linear
bractlets that originate from the base of the ovary; they are up to
twice the length of the scale. The blooming period occurs from mid- to
late spring as the vernal leaves begin to develop, lasting about 2
weeks. Afterwards, the female catkins are replaced by bristly fruits
that span about ¾" across; each fruit contains a cluster of nutlets at
its center and numerous bristly bractlets. At maturity, individual
are 3-5 mm. long, ovoid in shape, truncate-dentate on one
and rounded on the other.
root system can develop
clonal offsets from underground runners.
Clonal colonies of plants are common from such offsets.
The preference is full or partial sun, mesic to dry
conditions, and sandy soil. The root system of Sweet Fern can fix
nitrogen in the soil. This shrub is an alternate host of a blister rust
that infects Jack Pine (Pinus
The native Sweet Fern is rare in
where it is largely restricted to the NE section of the state.
It is state-listed as 'endangered.' Habitats include
upland sand prairies, sandy shrub prairies, and sandy upland savannas.
Dominant trees in these savannas are oak trees (especially Black Oak)
and sometimes pine trees are present (especially Jack Pine). Sweet Fern
benefits from occasional wildfires as this reduces competition from
taller shrubs and trees. The seeds can lie dormant in the soil for
several decades while waiting for such wildfires to occur.
Various insects feed on the foliage and
parts of Sweet Fern. These species include the leaf beetles
and Paria frosti
(Clark et al., 2004). The leafhopper Eratoneura parallela
sucks sap from this shrub. The caterpillars of several moths feed
primarily on the leaves of Sweet Fern, including Cleora sublunaria
(Double-Lined Gray), Cyclophora
(Sweetfern Casebearer Moth), Agonopterix
(Brown-Collared Agonopterix), Nemoria rubrifrontaria
(Red-Fronted Emerald), and Catocala
(Sweetfern Underwing); see
the Moth Table
more complete list of these species (Covell, 2005;
Wagner, 2005). Some vertebrate animals also use Sweet Fern as a source
of food. The Ruffed Grouse and Greater Prairie Chicken feed on the
buds, catkins, and foliage, while White-Tailed Deer and the Cottontail
Rabbit browse on the twigs and foliage (Martin et al., 1951/1961).
Because of its tendency to form colonies, Sweet Fern also provides good
cover for various animals.
A garden at the Kitty Todd Nature Preserve in
This shrub belongs to a monotypic genus that is endemic to
North America. It is related to the Bayberry shrubs (Myrica spp.
are found on
sandy coastlines along the Atlantic Ocean and Gulf of Mexico. Unlike
Sweet Fern, Bayberry shrubs produce waxy fruits. In spite of its common
name and the appearance of its attractive leaves, Sweet Fern is not
related to the true ferns. Perhaps its most notable characteristic is
the pleasant fragrance of its crushed leaves and twigs.