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Betulaceae
Distribution
Birch family.
Family with 6 genera about 170 species.
Distributed worldwide in northern
temperate areas as well as South American
mountains.
Important members
Alnus – Alder
Betula – Birch
Carpinus – Hornbeam
Corylus – Hazels
Ostrya – Hop hornbeams
Betulaceae
Family Characteristics
Temperate trees and shrubs.
Betulaceae
Family Characteristics
Leaves are simple, deciduous and alternate.
Betulaceae
Family Characteristics
Flowers unisexual catkins with male
and female flowers on the same plant.
Female
flowers
Male
flowers
Male flowers
Female flowers
Alder (Alnus)
Betulaceae
Family Characteristics
Fruits are a single-seeded nut. Some
seeds have a wing for wind dispersal.
Betula
Carpinus
Betulaceae
Economic uses
Landscape ornamentals
Timber
Nut crop - Hazel
Hazelnut (Corylus)
Betulaceae
Alnus glutinosa – European black alder
European black alder is a
medium-sized tree that is an
excellent choice for extremely
wet areas, although it does well
in drier soils as well.
It is native to Europe and
western Asia and has
naturalized in wet areas of
North America.
Alnus comes from Latin as “al”
for near and “nus ” for water.
Betulaceae
Alnus glutinosa – European black alder
Growth habit: Medium –sized trees
are pyramidal and can be grown
with a single or multiple trunks.
Tree size: Height ranges to 60 feet
and 30 feet wide.
Betulaceae
Alnus glutinosa – European black alder
Flowers: Male and female flowers
are separate on the same plant.
Male flowers are up to 4-inch
catkins hang at the terminal of
the branch.
Female
flowers
Brown catkins open to shed yellow
pollen before the leaves emerge.
Female flowers are reddish-brown
and egg-shaped.
Male
flowers
Betulaceae
Alnus glutinosa – European black alder
Fruit: The fruit is a small winged
nutlet borne in a globose
1/2-inch-long woody pine cone-like
dry catkin.
The fruit matures and is wind
disseminated in late autumn and
the dry catkin persists through
winter.
Betulaceae
Alnus glutinosa – European black alder
Leaf - Leaves are alternate, simple,
up to 4 inches long.
The leaf margin is doubly serrate
and the leaf tip has a deep notch
(obcordate).
Leaves are a dark, green in summer,
and green or brown in autumn.
Notch
Betulaceae
Alnus glutinosa – European black alder
Buds: The buds are rounded and
produced on an obvious short stalk.
Short
stalk
Betulaceae
Alnus glutinosa – European black alder
Culture:
Full sun or part shade.
Plants do well in wet areas.
It also does well in infertile areas
because plants have the ability to
fix nitrogen.
They are adaptable to a range of
soil types and pH.
Hardy in zones 7 to 4.
Betulaceae
Alnus glutinosa – European black alder
Cultivars:
‘Laciniata’ is a popular cut leaf form
that presents a finer texture than the
species, especially in young trees.
Betulaceae
Alnus glutinosa – European black alder
Cultivars:
‘Imperials’ has extremely deeply cut
leaves, even more so than ‘Laciniata’.
Betulaceae
Betula nigra – River birch
River birch has become a
very popular medium-sized
tree.
It is native to Eastern North
America including Kentucky.
It naturally occurs along
moist stream banks.
Betulaceae
Betula nigra – River birch
River birch can be used as a
screen or shade tree, and as
a street tree with irrigation.
River birches are attractive
when planted in groups,
especially against a dark
background.
Betulaceae
Betula nigra – River birch
River birch can be grown with
a single trunk or as a multiple
trunk tree.
Multiple trunks are best
utilized in groups of three
rather than two or four.
Betulaceae
Betula nigra – River birch
Growth habit - Pyramidal when young, oval
at maturity with an irregular crown.
Tree size: 40 to 70 feet tall, can reach 90
feet, with a 40- to 60-foot spread.
Young plants have attractive peeling bark.
Betulaceae
Betula nigra – River birch
Young trees can have peeling bark,
but older trees tend to have a graybrown flaky or furrowed bark.
Betulaceae
Betula nigra – River birch
Flower – Male flowers are up to 3-inch
long, catkins that are clustered at the
tips of the branches and drooping.
Female flowers are small catkins with
stigma that extend between the scales.
Female
flowers
Female
flowers
Male
flowers
Betulaceae
Betula nigra – River birch
Fruit – The fruit is a small nutlet
in a 1 to 2-inch long pendulous
catkin.
Fruit ripens in spring and the
winged nutlets are wind dispersed.
Catkin
Winged
nutlets
Nutlet
Betulaceae
Betula nigra – River birch
Leaf - Alternate, simple, up to 4
inches long and 2 inches wide.
Leaf margin is doubly serrate.
Doubly serrate
Leaf shape is
deltoid to
rhombic.
Betulaceae
Betula nigra – River birch
Leaf – Leaf color is medium to dark green
in summer, leaves turn yellow in fall, but
they drop quickly and therefore do not
provide a significant autumn display.
Betulaceae
Betula nigra – River birch
Culture:
Full sun or part shade.
River birch likes moist, fertile
soil with a pH of 6.5 or less.
It is short-lived in urban areas,
lasting 30 to 40 years. It lives
longer when planted in moist
areas.
Betulaceae
Betula nigra – River birch
Culture:
River birch is the most troublefree of the birches with little
insect or disease problems.
It is resistant to bronze birch
borer and leaf miner.
Betulaceae
Betula nigra – River birch
Culture:
River birch can develop iron
chlorosis if planted in high pH soils.
Betulaceae
Betula nigra – River birch
Culture:
In some years, leaf spot and aphids
can be a problem.
Leaf spot
Aphids
Betulaceae
Betula nigra – River birch
Culture: River birch is prone to ice storm damage.
Betulaceae
Betula nigra – River birch
Uses:
Even without the white bark of
youth, large river birch can be
effective shade trees with
filtered sunlight that permits
growth of other plants beneath
the canopy as long as the soil does
not dry out.
Betulaceae
Betula nigra – River birch
Uses:
River birch is often used as a
single specimen plant, but it is
also very effective when
planted in mass and limbed-up to
expose the exfoliating bark.
Repeating the three trunk
groupings of spaced trees in a
curvilinear pattern works to
follow the building’s pattern and
buffer pedestrian traffic
walkway from the man-made
structure.
Betulaceae
Betula nigra – River birch
Cultivars:
Dura-Heat (‘BNMTF’) is a
cultivar selected for its
white bark coloration and
good heat tolerance for
southern landscapes.
It also shows good tolerance
to aphids and leaf spot.
Betulaceae
Betula nigra – River birch
Cultivars:
Heritage (‘Cully’) is
possibly the most planted
river birch cultivar. It is a
vigorous grower selected
for good white flaky bark.
Heritage is a much better
choice than seedlinggrown river birch.
Seedlings are slower
growing with variable bark
coloration.
Young bark color.
Older bark color.
Betulaceae
Betula nigra – River birch
Cultivars: Fox Valley (‘Little King’) is a smaller, slower growing selection
with a rounded habit.
Betulaceae
Betula nigra – River birch
Cultivars:
Tecumseh Compact is
another compact, slower
growing selection with
arching branches.
Betulaceae
Betula nigra – River birch
Cultivars:
‘Summer Cascade’ is a
weeping form that is usually
grafted onto a standard.
It is a graceful plant that
can get 15 feet tall.
Betulaceae
Betula pendula – European white birch
European white birch is an
exceptionally ornamental mediumsized tree prized for its
pendulous growth and white bark.
Unfortunately, it is short-lived
because of its susceptibility to
bronze birch borer. In most
landscapes, European white birch
has been replaced with white
barked river birch cultivars that
are resistant to the borer.
Native to Northern Europe.
Betulaceae
Betula pendula – European white birch
Growth habit - Pyramidal when young,
then becoming oval pyramidal to oval
at maturity. Branches are pendulous.
Tree size: 40 to 50 feet tall with a
20 foot spread.
Betulaceae
Betula pendula – European white birch
Female
flowers
Flower - Male flowers are up to
3 inches long as a slender,
catkin drooping in the leaf axils.
Female flowers are cylindrical,
narrow catkins up to 1 inch long.
Male
flowers
Betulaceae
Betula pendula – European white birch
Fruit – The fruits are small nutlets
enclosed in a pendulous catkin that
ripens in autumn, but may not shed the
winged fruits until the following spring.
Current season’s
female flowers
Last season’s
fruits
Betulaceae
Betula pendula – European white birch
Leaf - Alternate, simple leaves are
diamond-shaped and up to 3 inches
long with a tapering tip.
Leaves, which are doubly serrate,
are a lustrous dark green in summer
and yellow or yellow-green in fall.
Betulaceae
Betula pendula – European white birch
Bark – Bark on young trees is an attractive white,
turning almost black with age.
Betulaceae
Betula pendula – European white birch
Culture:
Full sun.
European white birch tolerates dry
soils but grows best in moist, welldrained sandy or loamy soils.
Irrigation should be used during
drought conditions to prevent
stress that can make trees more
susceptible to insect attack.
Hardy in zones 6 to 2.
Betulaceae
Betula pendula – European white birch
Culture:
Bronze birch borer is a major pest
on white barked birches and is
especially bad on European white
birch.
The first signs of the insect is
terminal branch die-back.
The insect eventually kills the tree.
Betulaceae
Betula pendula – European white birch
Culture:
Birch leaf miner is also a
significant insect pest on
European white birch.
A fly lays eggs on emerging
leaves and the larvae tunnels
between the leaf layers.
Betulaceae
Betula pendula – European white birch
Cultivars (several):
‘Gracilis’ is a popular cultivar
with finely cut leaves and
drooping branches.
Betulaceae
Betula pendula – European white birch
Cultivars:
Purple Rain (‘Monte’) is the
purple rain weeping birch. It
has lustrous purple foliage and
slightly pendulous branches.
Betulaceae
Betula pendula – European white birch
Cultivars:
‘Youngii’ is a common cultivar that is a slow-growing, spreading form,
reaching a height of 15 to 20 feet with a spread of 20 to 25 feet.
Betulaceae
Betula pendula – European white birch
Cultivars :
‘Tristis’- Slow growing
plant with crooked
branches that hang
down from a central
leader.
There are massive
plants in Europe that
are very impressive.
Betulaceae
Carpinus betulus – European hornbeam
European hornbeam is larger than
American hornbeam, with larger leaves
and a spreading form that tends to
make it grow as wide as it is tall.
It is grown more than any other
non-native hornbeam.
Betulaceae
Carpinus betulus – European hornbeam
Growth habit - Pyramidal when
young, oval-rounded or rounded
when mature. Fine textured.
Tree size: 40 to 60 feet tall and
30 to 40 feet wide; can reach a
height of 70 to 80 feet.
Betulaceae
Carpinus betulus – European hornbeam
Flowers - Male and female flowers
are produced separately on the
same plant in pendulous catkins.
Female
flowers
Female
flowers
Male
flowers
Betulaceae
Carpinus betulus – European hornbeam
Fruit – The fruit is a small nutlet
located at the base of a two to
three-lobed bract. Paired fruits
hang in pendulous clusters. Fruits
mature in September to October.
Bract
Nutlet
Bract
Betulaceae
Carpinus betulus – European hornbeam
Leaf - Alternate, simple, up to 5
inches long and 2 inches wide.
Autumn color is bronze to yellow.
Betulaceae
Carpinus betulus – European hornbeam
Leaf – The tip of the leaf narrows to a
point and the leaf margin is sharply
doubly-serrate.
The leaf veins on the upper surface are
ridged giving a wave-like appearance.
Betulaceae
Carpinus betulus – European hornbeam
Buds – Lateral buds are sharply
pointed and often curve around
the stem.
The overlapping (imbricate)
scales have straight pubescent
hairs.
Betulaceae
Carpinus betulus – European hornbeam
Trunk – The bark on older plants
is gray and can be wonderfully
fluted and muscled.
Betulaceae
Carpinus betulus – European hornbeam
Culture:
Full sun or partial shade.
European hornbeam does
well in all soil textures and
can handle alkaline and
acidic situations.
It can handle moderate to
difficult city environments.
Hardy in zones 7 to 5.
Betulaceae
Carpinus betulus – European hornbeam
European hornbeam tolerates
pruning very well and can be
used for hedging and screens.
It is a common hedging plant,
especially in European gardens.
Betulaceae
Carpinus betulus – European hornbeam
European hornbeam
makes a great aerial
hedge, similar to the way
European beech (Fagus
sylvatica) is used.
This is a great way to
show off the fluted, pale
gray trunks and to define
spaces in a formal garden
design.
Betulaceae
Carpinus betulus – European hornbeam
European hornbeam is used in this aerial hedge at Dumbarton Oaks in
Georgetown. It is a particularly good choice because it frames the outdoor
room and provides interest along the path with its muscle-like trunk structure.
Betulaceae
Carpinus betulus – European hornbeam
One of the most impressive uses of
European hornbeam is at the Queen’s
Garden at Het Loo in the Netherlands.
There is a pleached arbor of European
hornbeam trained over a tunneled
corridor complete with windows.
Betulaceae
Carpinus betulus – European hornbeam
Cultivars: ‘Fastigiata’ is a commonly grown dense, compact tree that is
narrow when young, becoming oval with age. It does not maintain a
central leader as it ages.
Betulaceae
Carpinus betulus – European hornbeam
Cultivars:
‘Columnaris’ is similar to
‘Fastigiata’ but it tends to
form an oval or egg-shape
because it maintains a
central leader.
It can grow 30 feet tall and
wide.
Betulaceae
Carpinus betulus – European hornbeam
Cultivars:
‘Globosa’ is another slow growing
upright plant with a rounded
form.
It is densely twiggy near the
outline of the plant.
Slower growing than ‘Fastigiata’.
Betulaceae
Carpinus betulus – European hornbeam
Cultivars:
‘Franz Fountaine’ is a narrow,
columnar tree that can grow 35 feet
tall and 15 feet wide, it is the most
narrow European hornbeam cultivar.
Betulaceae
Carpinus betulus – European hornbeam
Cultivars: ‘Pendula’ is an irregular weeping form. Large plants are very
impressive . Old specimens can be 30 feet tall and twice as wide.
Betulaceae
Carpinus caroliniana – American hornbeam
American hornbeam is a good
specimen tree and is a wonderful
addition to a natural landscape.
The trunk and branches of this
tree have ridges that look like
muscles.
Native along stream beds in North
America from Canada to Florida,
west to Texas.
It is not as commercially available
as European hornbeam.
Betulaceae
Carpinus caroliniana – American hornbeam
Growth habit - Pyramidal when
young, plants become rounded to
spreading with age. Trees are
usually low branched unless
pruned.
Tree size: 20 to 30 feet tall and
30 feet wide, but can get larger.
Betulaceae
Carpinus caroliniana – American hornbeam
Flowers - Male and female flowers are
produced separately on the same plant in
pendulous catkins that appear in April.
Female
flowers
Male
flowers
Female
flowers
Male
flowers
Betulaceae
Carpinus caroliniana – American hornbeam
Fruit – The fruit is a nutlet located at the
base of the yellow to reddish lobed bract.
The paired fruit are held in loose
pendulous clusters. The fruit matures in
September to October.
Nutlet
Bracts
Nutlets
Betulaceae
Carpinus caroliniana – American hornbeam
Leaf - Alternate, simple, up to 5 inches
long and 2 inches wide.
Autumn color is yellow to orange-red.
Betulaceae
Carpinus caroliniana – American hornbeam
It can be difficult to distinguish
American and European
hornbeams. Several of the key
features besides fall leaf color
include leaf and bud characters.
Leaves – Leaves of both European
and American hornbeam are
doubly-serrate with European
hornbean tending to be more
sharply serrate.
Carpinus caroliniana
European hornbeam tends to have
more branching leaf veins leading
to the serrate tips (arrow).
Carpinus betulus
Betulaceae
Carpinus caroliniana – American hornbeam
Leaves – The veins on the
undersides of both the European
and American hornbeams have
pubescence.
In the American hornbeam the
hairs are tufted in the axils of
the main veins, while in European
hornbean the hairs are straight
along the main veins.
Carpinus caroliniana
Carpinus betulus
Betulaceae
Carpinus caroliniana – American hornbeam
Buds – Lateral buds of American hornbeam are shorter and straight.
The hairs are tufted in the bud scales rather than being straight and loose in
European hornbeam. European hornbeam buds also tend to curve toward the stems.
Carpinus caroliniana
Carpinus betulus
Betulaceae
Carpinus caroliniana – American hornbeam
Trunk – The trunk on American
hornbeam is attractive, but does
not take on the exaggerated
fluted, muscle-like appearance
of European hornbeam.
Betulaceae
Carpinus caroliniana – American hornbeam
Culture:
Full sun or partial shade.
American hornbeam does well
in most garden soils, but
prefers a deep, organic
slightly acidic soil.
Best handled as a containergrown plant.
Hardy in zones 9 to 3.
Betulaceae
Carpinus caroliniana – American hornbeam
Culture:
American hornbeam can be
pruned in a similar fashion
to European hornbeam.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Harry Lauder’s walking stick
is a selection of European
filbert with twisted
contorted stems and leaves.
It is useful as a large
specimen shrub for winter
interest.
The genus name comes from
the Latin for helmet (korys)
referring to the elongated
sepal tissue that covers the
fruit.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Growth habit – A slowgrowing plant with an
upright, rounded habit.
Twisted branches makes
an interesting winter
specimen.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Plant height - Can reach
15 feet in height and 10
feet wide.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Flowers – Male and female flowers are
produced separately on the same plant
in February.
Male flowers are pendulous catkins.
Female flowers have red styles
protruding from the bud.
Female flowers
Male flowers
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Fruit – Fruits are rarely produced on
Harry Lauder’s Walking stick because
they are self-sterile and require a
pollinator. The true species of European
filbert (C. avellana) is produced
commercially for its edible hazel nuts.
Commercial hazel nuts
A rare fruit produced on
Corylus avellana ‘Contorta’
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Leaf – Alternate, simple leaves are
broadly ovate with a double serrate
margin.
The leaves and stems are more twisted
on the cultivar than the species.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Buds – Male buds visible during the
winter as elongated terminal groups
and can provide additional winter
interest, especially after an ice storm.
Male flower buds
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Culture:
Full sun or light shade.
An easy plant to grow.
Tolerant to most landscape
soils.
Hardy in zones 8 to 4.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Culture:
Very attractive to Japanese
beetles that can cause severe
feeding damage to the leaves.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Culture:
Grafted plants can sucker and
make unsightly plants because
the rootstock produces nontwisted stems that quickly
over grow the slower growing
cultivar.
The nursery row to the right
is a layering bed where plants
will be produced on their own
roots. Plants produced by
layering do not have the
suckering problem.
Betulaceae
Corylus avellana ‘Contorta’ – Harry Lauder’s Walking stick
Cultivars:
‘Red Majestic’ is a purple foliage
version of Harry Lauder’s
walking stick.
Purple leaf color does not hold
into the heat of the summer.
The plant pictured here was
obviously propagated from
grafting, because the greenleaved rootstock (red arrow) is
sucking from the base of the
plant and will need to be pruned
away.
Betulaceae
Corylus avellana – European filbert
Cultivars: ‘Pendula’ produces a flat-topped plant with drooping
branches. It is usually grafted on a standard and is slow-growing.
Betulaceae
Birch family dichotomous key
Vegetative buds on short stalks.
Leaves with an indent or notch at the tip (emarginate) – Alnus glutinosa.
Leaves with rounded or acuminate (pointed) tip – Alnus cordata.
Vegetative buds not on short stalks (sessile).
Bark on young trees smooth or exfoliating; fruit a winged nutlet.
Bark white; twigs with prominent lenticles.
Leaves with a long petiole (>1 in.); leaf tip long and tapering – Betula populifolia.
Leaves with short petiole (<1 in.); leaf tips short acuminate.
Leaf lower surface pubescent at veins – Betula papyrifera.
Leaf lower surface glabrous (no hairs); branchlets hanging – Betula pendula.
Bark on young trees usually reddish-brown, orange-brown; twigs without lenticels.
Bark on young stems with a wintergreen scent when scraped – Betula lenta.
Bark without wintergreen scent – Betula nigra.
Bark does not exfoliate; fruit if present is a nut or nutlet enclosed in a leafy bract.
Stems twisted; leaves ovate, as long as wide – Corylus avellana ‘Contorta’.
Stems not twisted; leaves oblong, longer than wide.
Fruit a nutlet enclosed in an inflated “hop-like” bag – Ostrya virginiana.
Fruit a nutlet contained within leafy bracts.
Buds with few straight hairs and bud > 4 mm (0.16 in.) – Carpinus betulus.
Buds with tufted hairs and bud < 4 mm (0.16 in.) – Carpinus caroliniana.