Growing Tips and Identifying Alder Species
The Spruce / Evgeniya Vlasova
Alder trees and shrubs (Alnusspp.)
are members of the Betulaceae family, more commonly known as thebirchfamily.
These deciduous trees are moderate to fast-growing and will grow at a rate of about two feet per year.
The Spruce / Evgeniya Vlasova
The most notable features of all varieties of alder trees are their catkins and strobiles.
Both male and female flowers (catkins) appear on the trees.
The plant is wind-pollinated.
The Spruce / Evgeniya Vlasova
When the female flowers are pollinated, they mature into small cones (called strobiles).
The fruiting parts of the tree are edible.
Alders are also excellent hosts for many moth and butterfly larvae, and birds are attracted to the strobiles.
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The flowers attract pollinators, and the male flowers produce pollen profusely.
Growing Tips
Adler trees can fix nitrogen in the soil and grow in less-than-fertile areas.
Plants withnitrogen fixationcapabilities form symbiotic relationships with bacteria, allowing them to improve the soil on recently cleared land.
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This quality allows them to grow in landscaping areas where other plants may struggle.
Here are 12 common alder trees and shrubs for your landscaping needs.
Green Alder
The green alder is one of the smaller species and is a largeshrubor small tree.
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Its shiny green leaves have a yellow hue.
crispa),A. viridissubsp.fruticosa,A.
viridissubsp.maximowiczii(sometimesA.maximowiczii),A. viridissubsp.sinuata,(sometimesA.
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These alder trees have smooth, gray bark and the underside of the leaves also has a gray appearance.
While most other alder trees produce yellow catkins, this tree has reddish-purple catkins that appear each spring.
Hazel Alder
This species is either a shrub or a small tree.
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It tends to clone itself throughsuckers, forming a dense thicket of alders if left unchecked.
The species nameserrulatarefers to the margins of the leaves, which are toothed.
These alder trees are most prevalent in the eastern part of North America.
Robert H. Mohlenbrock / USDA-NRCS PLANTS Database
The species namecordatatips you off that this has cordateor heart-shapedleaves.
For this reason, it’s aptly known as the Pacific Coast alder or Oregon alder.
The bark can be used to make different colors of natural dyes.
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Fender has used red alder as the hardwood of choice for its electric guitars since the 1950s.
An alternative Latin name for this species isAlnusmetroporina.
There are three different subspecies of the seaside alder: subsp.georgiensis, subsp.oklahomensisand subsp.maritima.
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Some of the tallest specimens of this species have been known to reach 100 feet.
The tree gets its common name from its bark color, which ranges from white to gray.
Korea, and parts of China.
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This small variety of alder grows quickly to a mature height of 12 to 25 feet.
It features a dense canopy of slender, oval-shaped green leaves.
Usually deciduous, in some climate zones Japanese alder is evergreen in nature.
Michael Kurz/ Wikimedia Commons /CC BY-SA 3.0
Like other alder specimens, it does well in nutrient-deprived soil or wet conditions.
Its most eye-catching feature is its vivid green leaves with deeply serrated edges.
Check with your local extension office to verify it’s not classified as an invasive species in your area.
Krzysztof Ziarnek / Wikimedia Commons / CC BY-SA 4.0
The wedge-shaped leaves are dark green, glossy, and feature a small-toothed margin.
Don’t confuse this tree with the Japanese alder; theorientalisvariety hails from the coastal Mediterranean region of Turkey.
This tree is known for its useful applications, including providing dye or hardwood for furniture-making.
The bark is also said to have herbal qualities.
The alder tree family includes smaller shrubs and towering trees.
If you’re looking for otherfast-growing shade trees, considermapleorelmtrees.
They tend to be messy and unsightly, which makes people look towards other species for their landscape needs.
These trees also provide habitat for a wide range of wildlife.
The black alder tree,Alnus glutinosa, is also known as common alder and European alder.
There are many other alder species with various other names.
Alder trees and birch trees are very closely related.
University of Minnesota
Alnus cordata | italian alder/rhs gardening.
