smooth alder (Alnus serrulata)
Betula serrulata Aiton
Alnus americana K.Koch
Alnus autumnalis Hartig ex Garcke
Alnus glutinosa var. autumnalis Kuntze
Alnus glutinosa lusus obtusifolia Regel
Alnus glutinosa var. serrulata (Aiton) Regel
Alnus incana var. serrulata (Aiton) B.Boivin
Alnus latifolia Desf.
Alnus macrophylla Desf. ex Steud.
Alnus noveboracensis Britton
Alnus oblongata (Aiton) Willd.
Alnus rubra Desf. ex Steud.
Alnus rugosa Regel
Alnus rugosa var. obtusifolia (Regel) H.J.P.Winkl.
Alnus rugosa var. serrulata (Aiton) H.J.P.Winkl.
Alnus serrulata forma emarginata Fernald
Alnus serrulata var. macrophylla Spach
Alnus serrulata forma mollescens Fernald
Alnus serrulata forma nanella Fernald
Alnus serrulata forma noveboracensis (Britton) Fernald
Alnus serrulata var. obtusifolia (Regel) Regel
Alnus serrulata var. subelliptica Fernald
Alnus serrulata var. vulgaris Fernald
Betula alnus var. serrulata (Aiton) Michx.
Betula oblongata Aiton
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name of smooth alder
is Alnus serrulata (Aiton) Willd. Smooth alder is the only alder native
in south-eastern United States, where it is common and widespread,
Alnus incana subsp. rugosa hybridizes with Alnus serrulata. Extensive
hybrid swarms occur where the ranges of these species overlap, including
the area along the St. Lawrence River and the southern edge of the Great
Lakes. The two species and their hybrids are usually easily distinguished
by leaf shape and margin characters.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Smooth alder is a
large, spreading shrub with several trunks, sometimes a small tree, com-
monly found at edge of water. It can reach a height of 20 feet (6 m) with a
trunk diameter of 4 inches (10 cm). Stems are often twisted. The bark is
thin, dark gray to brown and smooth, with the trunk fluted. Twigs are red-
dish brown with gray fuzz and a 3-angled pith; the buds are stalked, plump,
covered in 2 to 3 red-purple scales, and resemble a match head. Leaves are
alternate, simple, obovate to elliptical, 2 to 4 inches long, pinnately-veined,
with a finely serrated wavy margin, dark green above, paler and finely
hairy beneath. Double toothed with small teeth between large teeth. The
base is V-shaped, not wedge-shaped. The leaves are in 3 rows, gummy
and aromatic when immature. Leaves turn red-brown in autumn. Flowers
are tiny, appear in early spring, with male green-brown flowers in drooping
catkins, 1 to 1 1/2 inches, and female flowers 1/2 inch long, reddish. Female
cones are in clusters of 4-10; elliptical, dark brown, hard, short-stalked;
maturing in late summer or autumn and remaining attached; with tiny egg-
shaped flat brown nutlets. The fruit is a woody, cone like catkin, 1/2 inch
long, dark brown with each scale enclosing a tiny, winged seed. Fruit ripens
in fall and is very persistant.
REGENERATION PROCESS: Both the male catkins and the female
flowers form in fall and open very early in spring (March - April), mostly
before the leaves come out.
SITE CHARACTERISTICS: Smooth alder refers a heavy soil and a damp
situation; in particular, it grows well in heavy clay soils (although is survives
in a wide range of moist to dry situations). The plant prefers acid, neutral
and basic (alkaline) soils. It will tolerate very infertile sites. It requires a
position in full sun, dying out when shaded by taller trees. This species has
a symbiotic relationship with certain soil micro-organisms, these form
nodules on the roots of the plants and fix atmospheric nitrogen. Some of this
nitrogen is utilized by the growing plant but some can also be used by other
plants growing nearby.
SUCCESSIONAL STATUS: Hazel alder is an aggressive, moisture loving
shrub, often used as a wetland restoration species. It is successful in initial
and mid-successional environments, and can sustain itself in more mature
peripheral situations, such as stream banks, ditches, edges of sloughs,
swampy fields and bog, and lakeshores. It is considered, however, intole-
rant to mature canopy situations, being replaced by more tolerant species.
Even though is short lived, it forms self-regenerating colonies by means of
SEASONAL DEVELOPMENT: Hazel alder blooms in early spring
(March - April).
GENERAL DISTRIBUTION: Within its geographical distribution area,
hazel alder can be found in almost every environmental situation that in-
cludes water - lake shores, swamps,
SKY MEADOWS DISTRIBUTION:
Shrub specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Occurs along
streams, ponds, swamps, and other low wet areas, often in pure stands.
Hazel alder grows in association with red maple, willow (Salix spp.)
swamp cottonwood, and river birch. Understory associates are button-
bush, greenbriar, roughleaf dogweed, hawthorns, planetree, trumpet
creeper and morningglory.
IMPORTANCE AND USES: Smooth alder is used predominantly for
streambank stabilization and wetland restoration. It is also a critical
cover component of woodcock habitat.
The roots have the ability to fix nitrogen, making it a good plant to rehabil-
itated depleted soils. It provides valuable food and shelter to a host of wet-
land birds and small mammals.
Various preparations of Alnus serrulata were used medicinally by Native
Americans to alleviate pain of childbirth, as a blood tonic, an emetic and
purgative, for coughs and fevers, to stimulate kidneys, to bathe hives or
piles, for eye troubles, indigestion, biliousness, jaundice, heart trouble,
mouth soreness in babies, and toothaches, to lower blood pressure, and to
clear milky urine.
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