Sunday, January 17, 2010

Alders - Useful Trees for Swampy Sites

A genus of 25 species of trees related to the Birches. Most are deciduous though there are a few exceptions. Most Alders are fast growing trees that in the wild colonize bare ground protecting the seedlings of more permanent trees such as Oak and Hickory. Alder grows frequently sprout up from distubed ground that is moist suck as clearings though many Alders also grow in swampy areas where competition is sparse. Colonization of Alder is aided by the seeds being light weight and easily carried by wind.
The wood is used for paper pulp, plywood, veneer, furniture and fenceposts. The wood does not scatter sparks making it favored for firewood. Alder can be coppiced every 10 to 20 years if cut during late fall or early spring. In this way one can have a sustainable supply of Alder timber products.
Many Alders even grow well in poor soil due to nitrogen fixing fungi in the roots enabling the trees to produce their own food. The fallen leaves from the Alder provide nitrogen rich fertilizer to new plants emerging on the forest floor. An acre of Alder trees can add up to 150 pounds of Nitrogen to the soil in a year.
Alder is highly valuable planted as a colonizer plant for reforestation and to protect prized crops from climatic extremes.
Propagation is typically from seed gathered from the cones immediately upon ripening during late summer then sown immediately. The planted seed usually needs stratification over the winter and should not be covered since light stimulates germination. It the seed does not naturally go through a cold period, then it is recommended to stratify it at 35 F for 3 months.
Alders can also be reproduced from hardwood cuttings taken in winter.
Prune all Alders in autumn as they will bleed sap if pruned in spring.
Young trees should be pruned to a single leader, thinned and feathered. Older trees rarely need much pruning.
Alders are excellent substitutes for Poplars and Willows on wet swampy soils.

Alnus acuminata ( Evergreen Alder )
A broad crowned tree reaching up to 80 feet that is native from Mexico south to northern Argentina. Records include: fastest recorded growth rate - 9 feet; 10 years - 80 feet with a trunk diameter of 20 inches; 30 years - 120 feet with a trunk diameter of 3.5 feet; largest on record - 140 feet with a trunk diameter of 6 feet.
This Alder is frequently planted in Australia and New Zealand.
The sharply serrated, taper pointed, drooping, elliptical leaves are semi-evergreen to evergreen depending on climate and are up to 8 x 7 inches in length.
The foliage is deep green in color.
The showy brownish-yellow flower catkins are borne in late winter.
The bark is silvery and smooth.
Hardy zones 8 to 10, tolerates at least down to 10 F and possibly 0 F.
Heavy clay, flood and drought tolerant however prefers a climate with 40 to 120 inches of rainfall per year and a soil PH from 4.5 to 7.

* photo of unknown internet source


Alnus cordata ( Italian Alder )
An extremely fast growing, very dense, handsome tall tree reaching up to 90 feet that is native to southern Italy and the islands of Corsica and Sardinia. Some records include: fastest recorded growth rate - 8 feet; 5 years - 23 feet; 20 years - 90 x 40 feet; Largest on record - 120 x 50 feet with a trunk diameter of 4 feet.
The horizontally held, finely toothed, broadly rounded leaves are up to 5 x 4 inches.
The foliage is orangish at first turning smooth shiny deep green above, light green beneath turning to bronze late in autumn.
The male flower catkins, up to 6.5 inches in length are yellowish and are borne in clusters of 3 to 5 at the branch tips.
The red female flower catkins are borne in short, upright clusters. They are followed by brown woody cones up to 1.3 inches in length that are borne in groups of 3.
The red-brown twigs have long stalked buds.
The pale gray bark is smooth becoming fissured with age.
Hardy zones 4 to 8 on moist soil in full sun. Very soil tolerant including swampy and dry limey or chalky soils. In Ottawa, Ontario ( alltime low -39 F ) it is reduced to a shrub. Rarely bothered by pests or disease.

* historical archive photos

* photo of unknown internet source


Alnus cremastogyne
A stately straight tree reaching up to 80 feet or more that is native to western China. Some records include: 5 years - 20 feet; 20 years - 60 feet; largest on record - 133 feet with a trunk diameter of 5 feet.
The finely-toothed, elliptic leaves, up to 6 inches in length, are semi-evergreen to evergreen in mild climates.
The rough bark is gray.
Hardy north to zone 6

Alnus x elliptica
A natural hybrid between Alnus cordata & A. glutinosa reaching up to 80 feet or more, that originated from Corsica in the Mediterranean Sea. Some records include: largest on record - 165 x 80 feet with a trunk diameter of 7.5 feet.
The finely-toothed, narrowly-oval leaves are up to 6 x 4 inches in size. The foliage is deep green above and very slightly hairy beneath.
The flower catkins up to 0.7 inches appear in clusters of 2 to 5.
Hardy zones 6 to 10.

Alnus fauriei ( Miyama Alder )
A fast growing, small tree with a maximum size that is uncertain. Some records include: 8 years - 30 feet with a trunk diameter of 7 inches. It is native to moist woods of Honshu Island in Japan.
The toothed, deeply-veined rounded, very attractive foliage is very glossy mid green. The oversized foliage is the most beautiful of all the Alders and this beautiful tree should be much more widely used in the landscape.
The attractive, showy flower catkins, up to 7 inches in length, are borne during early spring before the foliage emerges.
Hardiness in uncertain and this tree should be tested in North America. Due to its native range in snowy mountainous regions, it would probably thrive in much of the northeastern U.S. and southern Ontario, Canada.

Alnus ferdinandi-coburgii ( Chuandian Alder )
A fast growing, medium-sized tree, reaching up to 65 feet, that is native to Guizhou, southwest Sichuan and Yunnan Provinces in China. Some records include: 13 years - 33 feet.
The attractive, oval leaves, up to 6.5 x 3 inches, are luxuriant glossy mid-green.
The flower catkins are borne late spring or early summer.
The smooth bark is dark gray.
Hardiness in uncertain but it may prefer more maritime climates such as the British Isles.

Alnus firma ( Japanese Alder )
A very rare, graceful, broad, medium-sized tree reaching up to 43 feet that is native to mountains of Japan, though now also naturalized in Korea. Some records include: largest on record - 66 x 27 feet with a trunk diameter of 20 inches; longest lived - 100 years. It has been used to colonize areas with dry, sandy soils.
The prominently veined, sharply-toothed, pointed leaves, up to 5.3 inches in length, resemble that of the Carpinus - Hornbeam. The foliage is glossy deep green and remains green late in autumn.
The attractive flaking bark is gray revealing reddish bark beneath.
The abundant, bright golden-yellow flower catkins appear during early spring.
Hardy zones 5 to 9 in full sun on just about any well drained soil. It has survived as far north as Ottawa in Ontario ( Dominion Arboretum ) where it is reduced to being a shrub.

* excellent photo link found on internet
http://www.biolib.cz/en/taxonimage/id230469/?taxonid=1083748

Alnus formosana ( Formosan Alder )
An impressive tree that is closely related to Alnus maritima of North America, except that it is native to Taiwan. Largest on record - 100 feet with a trunk diameter of 10 feet. Lives to 80 years or more.
The elliptical leaves are up to 5 x 2 inches in size.
Hardy zones 7b to 9.

Alnus fruticosa ( Siberian Alder )
Also called Alnus mandshurica. A small to medium size tree native to Siberia, Manchuria and north Korea. Some records include: 24 years - 47 feet; largest on record - 47 feet. It is often multi-stemmed.
The toothed, broadly-ovate or elliptical leaves are up to 5 x 3.2 ( rarely over 4 ) inches in size. The foliage is glossy deep green.
The flower catkins appear during late spring or early summer.
The bark is smooth and dark gray.
Hardy zones 2 to 6.

* historic archive photo


Alnus glutinosa ( Black Alder )
A very fast growing, somewhat open, broadly-conical tree reaching up to 80 feet or more, that is native from most of Europe to Siberia, south into northern Africa. Some records include: 5 years - 17 feet; 20 years - 66 x 40 feet; largest on record - 165 x 80 feet with a trunk diameter of 7.5 feet.; largest in Iowa - 80 x 40 feet in Davenport; longest lived - 214 years. It is usually found in swamps and along riverbanks in the wild. It is sometimes found naturalized in northeastern North America.
The shallowly-toothed, broadly-rounded leaves are up to 6.5 x 5 inches in size. The foliage is smooth deep green above, light green and finely-hairy beneath, persisting very late in autumn.
The flower catkins are borne in early spring before the foliage emerges with both sexes occurring on the same plant.
The male flower catkins, up to 7.5 inches in length are dull purple turning to dark yellow and are borne in clusters of 3 to 5.
The female flower catkins are borne in short, upright clusters that transition from purple to deep red to green. They are followed by brown woody cones.
The bark is brown and smooth later turning dark with many warty stripes.
Hardy zones 2 to 8 preferring sun to partial shade on cool moist soil with a PH from 4.5 to 8. Very flood and lime tolerant and will even grow in swamps.

* photos taken on August 5 2010 in Clinton, Ontario



* photos taken on Aug 5 2017 @ Brookside Gardens, Wheaton, MD

* historic archive photos


'Aurea'
Smaller in size, reaching up to 50 feet with a trunk diameter of 2 feet.
It makes up for its smaller size with its very attractive bright golden-yellow spring foliage which later turns to bright green.

'Imperialis'
Also called 'Incisa'. An elegant fine-textured, broadly-pyramidal tree that is open in habit with deeply cut foliage. A medium size tree, with the largest on record being 66 feet with a trunk diameter of 33 inches. Excellent for waterside plantings where its weeping sprays of fine-textured foliage make it appear almost like a Kashmir Cedar during the summer months.

* photos taken by Milan Havlis, owner of central Europe's premier plant nursery

* photo taken on Aug 5 2017 @ Brookside Gardens, Wheaton, MD


'Laciniata'
Vigorous with deeply cut foliage. Largest on record - 85 x 85 feet with a trunk diameter of 50 inches.

'Pyramidalis'
A fast growing, narrow-columnar form, reaching up to 60 x 20 feet, that makes an excellent replacement for the Lombardy Poplar.

Alnus hirsuta ( Manchurian Alder )
Very fast growing, broadly-pyramidal tree reaching up to 30 feet that is native to Siberia, northeast China, Korea and Japan. Some records include: fastest growth rate - 6 feet; 10 years - 33 x 17 feet; 20 years - 47 feet; 46 years - 60 x 54 feet with a trunk diameter of 2.8 feet; largest on record - 80 x 54 feet with a trunk diameter of 2.8 feet. A large tree grows at Longwood Gardens near Philly, PA. It is closely related to Alnus glutinosa.
The toothed and lobed leaves are similar to that of Alnus incana but is larger, up to 6 x 5 inches. The foliage is dull deep green above, red-brown downy beneath and turn to yellow during autumn.
The fruits are larger than the similar Alnus incana.
The very attractive, smooth bark is light gray and Beech-like. The hard wood is valuable for making furniture.
Hardy zones 3 to 8 ( possibly zone 2..especially for Inner Mongolia seed source ) preferring fertile moist soil though tolerant of clay. The Manchurian Alder is the most drought tolerant of the Alders and is the best one for use in the Dakotas. It is rarely bothered by pests or disease.

* photo taken on March 28 2010 @ U.S. National Arboretum

* photos taken on 4th of July 2010 @ U.S. National Arboretum, D.C.


* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA



* historic archive photos


'Prairie Horizon'
Also called 'Harbin'. A very handsome, fast growing, strongly upright, medium-sized tree that reaches an average mature size of 50 x 30 feet.
The very attractive glossy deep green foliage turns intense golden-yellow during autumn.
It is otherwise similar to the species.

Alnus incana ( Gray Alder )
A vigorous medium size tree reaching around 60 feet that is native from the mountains of Europe to the Caucasus. It is also native to much of Scandinavia and western Russia. Some records include: fastest growth rate - 4 feet; 10 years - 34 feet; 20 years - 60 x 33 feet; largest on record - 100 x 50 feet with a trunk diameter of 2.8 feet; longest lived - 100 years. It has reached 40+ feet at Dominion Arboretum at Ottawa, Ontario.
The doubly-toothed, pointed, oval leaves are up to 5 x 3.3 inches. The foliage is dull deep green above and gray downy beneath.
The flower catkins are borne in early spring before the foliage emerges.
The drooping male catkins are reddish and up to 4 inches in length. The female catkin are small, upright and red. They are followed by woody cones up to 0.6 inches in length.
The bark is smooth and gray.
Hardy zones 1 to 7, tolerating cold and wet conditions.

* photo of unknown internet source




* photo of unknown internet source

* excellent photo link found on internet
http://www.biolib.cz/en/taxon/id3446/

'Aurea'
Young foliage is yellow. The flower catkins are orange-red.
Largest on record - 57 feet with a trunk diameter of 16 inches

'Coccinea'
Also called 'Ramulus Coccineus'. Red twigs and orange flower catkins.

'Laciniata'
Foliage is finely dissected, typically into 8 narrow lobes.
Largest on record - 47 feet with a trunk diameter of 26 inches

* excellent photo link found on internet
http://www.biolib.cz/en/taxonimage/id145701/?taxonid=828545

'Pendula'
Beautiful weeping form
largest on record - 45 feet with a trunk diameter of 28 inches.
It is more beautiful used next to water.

'Ramulus Coccineis'
Largest on record - 42 feet with a trunk diameter of 1 foot

Alnus japonica ( Japanese Alder )
A very dense, fast growing, pyramidal, medium-size tree reaching around 60 feet, that is native to far eastern Russia, northeast China, Korea and much of Japan. Some records include: fastest growth rate - 8 feet ; 20 years - 50 feet; largest on record - 100 x 50 feet with a trunk diameter of 4 feet. Lives up to 100 years or more.
The elliptical leaves, up to 8 x 4.5 ( rarely over 5.5 ) inches in size are deep green above and light green beneath. The Japanese Alder is early to leaf out in spring and the foliage is persistent in fall, lasting into November.
The flower catkins, up to 3 inches in length, are borne during early spring.
The bark is gray with reddish cracks.
Hardy zones 4 to 7 ( seed source from Jilin Province of China should also be tested in zone 3 ). It is very heat tolerant and thrives from the Mid Atlantic U.S. to Ottawa, Ontario and should be planted more there.


* photos taken on 4th of July 2010 @ U.S. National Arboretum, D.C.




* photos taken on Feb 8 2014 @ U.S. National Arboretum, DC



Alnus jorullensis
One of the few Alders native to mountainous areas of central America. It is similar to Alnus acuminata found in a similar natural range. Some records include:
10 years - 40 feet with a trunk diameter of 8.5 inches in Cornwall

Alnus lanata
A medium-size tree reaching around 60 feet that is native to western Sichuan China. Some records include: 29 years - 43 feet with a trunk diameter of 15 inches; largest on record - 100 feet with a trunk diameter of 3 feet.
The minutely-toothed, oblong leaves are up to 6 x 3 inches in size.
The bark is smooth and yellow-gray
Hardy zones 5 to 8.

Alnus maritima ( Seaside Alder )
Typically a shrubby narrow crowned small tree reaching around 40 feet that is native to Maryland and Delaware, U.S.A. as well as in Oklahoma. It is not known from anywhere between but may have been widespread in the eastern U.S. before the last ice age. Some records include: largest on record - 70 x 20 feet with a trunk diameter of 3 feet. It is endangered in the wild but makes a beautiful landscape tree.
The toothed, broadly-elliptic, leathery leaves are up to 6 x 2 inches in size. The foliage is glossy deep green and persists late in autumn.
This is one of the few Alders that flower in autumn, most being native to Asia. It was widespread in ancient times.
The branches zig-zag. The bark is smooth and light brown or gray.
Hardy zones 3a to 8 in full sun to partial shade, preferring a soil pH from 5 to 7. Flood and moderately salt tolerant. It is an excellent choice for swampy sites and even grows in standing water in the wild.


* photo taken by Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database. Northeast wetland flora

* historic archive photos

* excellent photo link found on internet
http://www.biolib.cz/en/taxonimage/id158945/?taxonid=195129

'September Sun'
A fast growing, dense, well shaped clone of A. maritima that was developed by Iowa State University using Oklahoma genotype. It is a highly recommended small landscape tree for both floodplains and upland sites.

Alnus maximowiczii ( Sakhalin Alder )
A fast growing, spreading, small to medium-sized, deciduous tree reaching around 33 feet that is native to far eastern Russia, Kamchatka, Sakhalin, Korea and high mountains of Japan. It is the Asian relative of Alnus sinuata. Some records include: largest on record - 100 feet with a trunk diameter of 3 feet; longest lived - 100 years.
The toothed and lobed, broadly-ovate leaves are up to 6 x 3.5 inches in size. The attractive foliage is bronze at first, turning to glossy deep green above, pale yellowish-green beneath.
The showy, yellow-green, hanging catkins, up to 4 inches long, appear during early spring just before the foliage emerges.
The rough bark is dark gray.
Hardy zones 4 to 7 ( will likely prove hardier with more testing ).

* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA




Alnus nepalensis ( Nepal Alder )
A tall open sparsely branches tree native to riverbanks in southwest China and the eastern Himalayas. Some records include: fastest growth rate - 9 feet with a trunk diameter increase of 1.3 inches; 9 years - 81 feet with a trunk diameter of 9 inches; 10 years - trunk diameter of 1 foot; 26 years - trunk diameter of 20 inches; largest on record - 100 x 40 feet with a trunk diameter of 7 feet.
The leaves, up to 9 x 5 inches, are glossy deep green.
The long male flower catkins up to 6 inches in length are borne in clusters of 10 or more at the branch tips in autumn rather than spring.
The smooth bark is silvery.
Hardy zones 7 to 10 tolerating as low as -4 F ( there is a wide variation in hardiness depending upon of elevation of seed source ). It is tolerant of temporary flooding but not swampy conditions. The large leaves are prone to scorching on sites with high winds and low humidity.

Alnus nitida ( Himalayan Alder )
One of the worlds fastest trees reaches up to around 90 feet and is native to the western Himalayas. Some records include: first year - 20 feet; 2 years - 30 feet; 60 years - 90 feet; largest on record - 120 feet with a trunk diameter of 5 feet. Lives up to 100 years or more.
The semi-evergreen to evergreen foliage is very glossy mid-green. The ovate leaves are up to 8 x 5 ( rarely over 7 x 4 ) inches in size.
The flower catkins, up to 10 ( rarely over 7.5 ) inches in length, appear early to mid-autumn.
The deeply-furrowed bark is dark brown to black.
Hardy north to zone 6 and is flood tolerant. It requires 30 + inches of yearly rainfall.

'Evergreen King'
More reliably evergreen, very vigorous and may grow all year in mild climates.


Alnus oblongifolia ( Arizona Alder )
Closely related to Alnus acuminata, this Alder is one of North Americas fastest growing native trees, reaching around 75 feet. The Arizona Alder is native to the mountains of Arizona and New Mexico; south into Mexico. Some records include: fastest recorded growth rate - 9 feet; 15 years - 37 feet with a trunk diameter of 1 foot; 30 years - 120 feet with a trunk diameter of 3.5 feet; ; largest on record - 130 x 58 feet with a trunk diameter of 6 feet.
The double-toothed, elliptical leaves are up to 3.5 x 2.5 inches in size. The leathery foliage is deep green above, light green and slightly hairy beneath.
The twigs are reddish-brown with long stalked, downy, blunt-tipped buds.
The bark is smooth and brown or gray, becoming cracked on older trees.
Hardy north to zone 7, surviving on the east coast as far north as Philadelphia.

Alnus orientalis ( Syrian Alder )
An extremely fast growing, handsome large tree closely related to Alnus cordata that can easily exceed 100 feet and is a widespread native to riverbanks from southern Turkey into Syria and Cypress
Some records include: fastest growth rate - ; 4 years - 30 feet; largest on record - 170 feet.
The uneven margined leaves are large, up to 10 x 4.5 inches.
The foliage is glossy deep green.
The young catkins and emerging buds are sticky on the surface.
Hardy zones 6 to 10 and possibly 5 ( reported to grow at Dominion Arboretum at Ottawa, Ontario ).

Alnus pendula
Also called Alnus firma multinervis however it is most certainly a separate species of Alnus that is similar to Alnus firma. This is a fast growing, medium-size tree reaching up to 60 feet that is native to much of Japan. Some records include: 12 years - 17 feet with a trunk diameter of 5 inches. Largest on record - 80 feet with a trunk diameter of 1.5 feet.
The oblong leaves are up to 5 inches in length.
The bright greenish-yellow flower catkins, up to 3 inches in length, appear during mid-spring.
The bark is smooth and reddish-brown.
Hardy north to zone 5

Alnus rhombifolia ( White Alder )
A fast growing, spreading, rounded-crowned, large tree reaching up to around 80 feet that is native to stream sides in the western U.S. ( from Washington State to western Montana; south to southern California ). The slender branches are pendulous towards the tips. Some records include: fastest growth rate - 7 feet; 5 years - 30 + feet; 20 years - 50 + feet; largest on record - 120 x 70 feet with a trunk diameter of 5 feet. It is rarely seen in eastern North America but has reached 50 feet at Dominion Arboretum in Ottawa, Ontario. The White Alder has a dense canopy that casts deep shade and is long lived.
The toothed, diamond-shaped leaves are up to 5.3 x 2.5 inches in size. The foliage is very downy at first turning to shiny deep green above and downy yellow-green beneath. Foliage tends to persist late in autumn and may be evergreen in mildest parts of range.
The flower catkins are up to 6 inches in length.
The bark is smooth and silvery.
Hardy zones 2 to 9 preferring soil PH from 6 to 7.5. It is heat and wind tolerant but does not enjoy drought. Use seed source from western Montana in colder, continental climates.

* photos of unknown internet source


* photos taken by Jean Pawek @ CalPhotos

* historical archive photo


Alnus rubra ( Red Alder )
A fast growing, handsome, dense-canopied, tiered, broadly-conical tree reaching up to 100 feet with a somewhat pendulous pyramidal crown; that is native to western North America ( from Skagway, Alaska to Iskut, British Columbia to near Kamloops British Columbia; south to central California ). Some records include: fastest recorded growth rate - 11 feet; 4 years - 37 feet with a trunk diameter of 7 inches; 12 years - 60 feet; 15 years - 66 x 33 feet; 20 years - 80 x 34 feet; largest on record - 180 x 75 feet with a trunk diameter of 9 feet; longest lived - 110 years. Thrives in England where it reaches 70 feet or more.
The toothed, oval to elliptical leaves are up to 6 x 3 or rarely as much as 12 x 4 inches in size. The leathery foliage is downy red-brown at first, becoming deep green above and blue-gray with some rusty-brown hairs beneath. The leaves turn to bronze and persist late in autumn.
THe flower catkins are borne in early spring with both sexes occuring on the same plant. The male catkins are drooping and yellow-orange, up to 10 inches in length.
The female catkins are upright, red and small. They are followed by woody cones up to an inch in length.
The young stems are deep red at first.
The bark is smooth and blue-gray with whitish blotches. Older trees have darker gray bark that breaks into flat plates and reveals red-brown inner bark.
Hardy zones 4 to 9, it also thrives in parts of the northeast and a shapely 50 foot tree grows at Dominion Arboretum in Ottawa, Ontario. It is shallow rooted requiring moist soil and hates shade.
Tolerates swampy conditions and poor soil.

* photos of unknown internet source


* photo taken by Jean Pawek @ CalPhotos

* photo taken by Constance A. Harrington @ USDA-NRCS PLANTS Database

* historical archive photos


Alnus rugosa ( Speckled Alder )
A small tree closely related to Alnus incana, that typically reaches around 25 feet and is native to northern North America ( from northwest Alaska to northeastern Yukon to western Northwest Territories to far northeast Saskatchewan to Churchill, Manitoba to far northern Ontario to Labrador & Newfoundland; south to Calgary, Alberta to North Dakota to northern Illinois to southern West Virginia to northern New Jersey ). In Ontario it is rare or absent south of Bruce County though may have been more common in the past. In the Windsor/Essex County, Ontario region; it occurred on wet sites along Lake St Clair during the 1800s. Some records include: fastest recorded growth rate - 4 feet; 20 years - 53 feet with a trunk diameter of 19 inches; largest on record - 70 x 60 feet with a trunk diameter of 1.6 foot. It is found in swamps, riverbanks and lakeshores in the wild.
The finely-toothed, oval leaves are up to 4 inches in length. The foliage is dull dark green and wrinkled above; rusty and downy beneath.
The male flower catkins up to 4 inches in length appear in early spring before the foliage emerges.
The bark is smooth and gray, heavily speckled with paler horizontal lenticels.
Hardy zones 2 to 7 ( likely 1 for northeast Alberta seed source ) and thrives on cold wet soils. Flood tolerant. Thrives in England

* photos of unknown internet source


* historic archive photo

* photos taken on July 14 2016 in Tobermory, ON

* excellent photo link found on internet
http://www.biolib.cz/en/taxon/id3444/

Alnus serrulata ( Hazel Alder )
Also called Smooth Alder. A small tree reaching around 30 feet that is native to swamps in eastern North America ( from Nebraska to northwest Indiana to the south shore of Lake Erie to Quebec along the St Lawrence River to New Brunswick and Nova Scotia; south to eastern Texas to northern Florida ). Some records include: fastest recorded growth rate - 4 feet; largest on record - 50 x 61 feet with a trunk diameter of 1 feet. Three very large trees grow in the Riverside Business Park in Asheville, N.C. and may currently be the largest of their kind.
The finely-toothed, ovate leaves are up to 5 x 3 inches in size. The foliage is deep green above and light green beneath.
The drooping purple flower catkins, up to 4 inches in length are borne in late winter.
The bark is smooth and brown with lenticals even on mature trees. The trunks are often fluted.
Hardy north to zone 4 ( should be tested in 2 and 3 ) and both very heat and flood tolerant. Rarely bothered by pests or disease.

* photos taken on Aug 20 2011 @ Brookside Gardens, Wheaton, MD


* photos taken on Mar 1 2012 in Columbia, MD

* photos taken on July 10 2013 in Columbia, MD

* photos taken on May 26 2014 in Columbia, MD

* photos taken on Oct 24 2014 in Columbia, MD

* photo taken on Sep 13 2015 in Columbia, MD

* photos taken on Aug 15 2016 in Columbia, MD

* photos taken on Sep 16 2016 @ Patuxent Research Refuge, Laurel, MD

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA


Alnus sieboldiana ( Siebold ALder )
A small tree, reaching up to 33 feet, that is native to upland sites the island of Honshu in central Japan. Some records include: 26 years - 30 feet with a trunk diameter of 11 inches.
The attractive toothed, ovate to broad-rounded leaves, up to 5 inches in length, are conspicuously veined. The luxuriant glossy mid-green foliage persists until the end of November.
The hanging yellow catkins appear during early spring.
Hardy zones 6 to 8 ( est - has not been tested in North America ) in full sun to partial shade. It is moderately drought tolerant.

Alnus sinuata ( Sitka Alder )
A rapid growing, open, narrow small tree reaching up to 35 feet that is native to northwestern North America ( from Alaska to the Yukon to western Alberta; south to southwest Oregon to central Montana ). Some records include: 20 years - 33 feet; largest on record - 56 x 30 feet with a trunk diameter of 3 feet. It is closely related to Alnus viridis.
The sharply double-serrate edged, ovate leaves are up to 6 x 4 inches. The glossy deep green leaves are borne on red stalks.
The flower catkins in early spring are up to 5 inches in length.
The bark is smooth gray-green with warty lenticels.
Hardy zones 2 to 6, thriving even in interior Alaska and northeastern Canada. It is shade tolerant and prefers a soil PH from 6 to 7.5. It is not tolerant of intense heat or drought.

Alnus x spaethii
A very attractive, very fast growing, dense, broad-pyramidal, large tree reaching around 80 feet that is the garden raised hybrid between Alnus japonica & Alnus subcordata. Some records include: 15 years - 50 feet; 20 years - 60 feet; largest on record - 100 feet with a trunk diameter of 4 feet. A popular street tree in Holland, it is very rare in the U.S.
The coarsely serrate-margined, lance-shaped leaves are up to 9.5 inches in length.
The foliage is purplish-red at first, turning to deep green above.
The young shoots are downy.
The showy catkins are up to 8 inches in length.
The bark is light gray and ridged.
Hardy zones 5 to 9; it breeds true from seed.

* excellent photo link found on internet
http://www.biolib.cz/en/taxonimage/id191613/?taxonid=915312

Alnus subcordata ( Caucasian Alder )
A large tree to 80 feet or more, that is native to temperate western Asia.
Some records include: fastest recorded growth rate - 7 feet; 4 years - 30 feet; 27 years - 66 feet with a trunk diameter of 1.4 feet; Largest on record - 120 feet with a trunk diameter of 3.6 feet.
The leaves, up to 10 x 4 inches are very large for an Alder and are late deciduous to semi-evergreen. The foliage is deep green.
The flower catkins, up to 6 inches in length are borne in February.
Hardy zones 5 to 8, it is fully hardy in Ottawa, Ontario where it has exceeded 45 feet.

Alnus tenuifolia ( Thinleaf Alder )
A fast growing, small tree to around 30 feet that is native to western North America ( from central Alaska to Yukon Territories, south in the Rockies to central California to Colorado ). Some records include: fastest recorded growth rate - 3 feet; 20 years - 30 feet; largest on record - 82 x 40 feet with a trunk diameter of 3 feet ( Umatilla NF in Washington State ).
The attractive double-toothed, oval to oblong leaves are up to 7 x 5 inches ( usually much smaller ) in size. The foliage is deep green with an orange-yellow midrib above, downy with rusty brown hairs beneath; turning to yellow during autumn.
The flower catkins borne in early spring are up to 4 inches in length.
The shoots are red and downy at first, later becoming smooth.
Hardy zones 1 to 7, thriving even in interior Alaska.

* photo of unknown internet source

* photos taken by Jean Pawek @ CalPhotos

* historical archive photos


Alnus trabeculosa ( Sakura Hazel )
A medium-size tree native to swampy sites in southeast China and southern Japan that is related to Alnus japonica. Some records include: largest on record - 82 feet.
The minutely-toothed, obovate leaves are up to 7 x 4 inches in size. The attractive foliage is very glossy deep green.
The reddish-orange, hanging flower catkins appear late winter into early spring before the foliage emerges.
The smooth bark is dark gray.
Hardy zones 5 to 8 and is flood tolerant. It is also very heat tolerant and thrives in the Mid Atlantic region of the U.S.

* excellent photo link
http://www.chinahorticulture.net/wp/cn/wp-content/uploads/sites/2/2013/07/72.jpg

Alnus viridis ( Green Alder )
Also called Alnus crispa for North American subspecies. An upright, large shrub reaching around 18 feet that is native to the central European Alps & Carpatian Mountains. It is also found in the Boreal Forest region of northern North America ( from northwest Alaska to north-central Northwest Territories to Nunavut to far northern Ontario to northern Quebec to the southern coast of Greenland, Labrador and Newfoundland; south to the high Rockies, northern Minnesota, the Upper Peninsula of Michigan to Midland, Ontario to Ottawa, Ontario to New England ). Some records include: 5 years - 13 x 8 feet; 60 years - 27 feet with a trunk diameter of 8 inches; largest on record - 30 x 12 feet with a trunk diameter of 8 inches. It is found on sand or gravel flats, bogs, riverbanks and lakeshores in the wild.
The toothed and very shallow lobed, broadly-oval leaves are up to 4 inches in length. The foliage is matt deep green above and glossy bright green beneath.
The yellow, male flower catkins, up to 5 inches in length, are upright at first though later becoming pendulous.
The bark on mature trees is gray and smooth except for the pale lenticels arranged in horizontal rows.
Hardy zones 1 to 5; hardy to as low as -82 F

* photo taken by Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database. Northeast wetland flora


'Grandiflorus'
More vigorous, reaching up to 26 feet with larger leaves, to 5 x 4 inches.

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