Albizia - Siris / Silk Trees

A genus of trees for both tropical and temperate climates, that are part of the larger Legume family. They are very easy to grow and tolerant of poor soils though grow best in well drained loam soils on a sheltered site. They like warm to hot, wet summers. The seeds generally germinate much better if they are treated first to soften the shells. This includes soiling them in sulfuric acid for 30 minutes then washing them in regular warm water immediately before sowing. Soaking seeds in just warm to hot water for a few days also works but is not as consistant.
They can also be reproduced from root cuttings at least 0.5 inches in diameter planted immediately in early spring.

Albizia adianthifolia ( Flat Crown )
Native to a huge chunk of Africa from the tropics to coastal Natal in South Africa; this is a large tree with a stocky trunk and a very wide, umbrella shaped canopy.
Both long lived and very fast growing, the maximum size is 150 x 110 feet with a trunk diameter of 4 feet, though obviously much smaller in dry regions with no irrigation. The bark is gray and smooth later becoming flaky and brown.
The leaves are up to 10 x 5 inches and are composed of leaflets up to 2 x 1 inch.
The white "powderpuff" flower heads appear in winter and spring. The flowers attract nectar feeding birds.
Hardy zones 9 to 12

Albizia amara
A very fast growing tree reaching up to 50 x 50 feet, that is native to south-central India. Some records include: 1st year from seed - 10 feet; 3rd year - 27 feet!
The feathery bipinnate leaves are up to 11 inches in length. The foliage is mid-green.
The flowers are creamy-white.
The smooth bark is dark green.
This tropical tree is only hardy from zones 10 to 12 and is both tolerant of clay and wet soils.

Albizia anthelmintica ( Worm-Cure False Thorn )
A deep-rooted, thorny, moderate growing, multi-stemmed, rounded to flat-topped, medium-sized, deciduous tree, reaching up to 27 x 40 feet in size. It is native to Tanzania and Mozambique in eastern Africa. Some records include: 3 years - 7 feet; 4 years - 10 feet; 7 years - 14 feet; 12 years - 17 feet.
The bipinnate leaves are composed of leaflets, up to 1.5 x 1.2 inches in size.
The puffball flowers are creamy-white.
The smooth bark is gray or brown.
The creamy-white, fluffy flowers are followed by pods up to 7 x 1.2 inches in size.
Hardy zones 9b to 11 in full sun. It thrives in the U.S. in southwest Arizona with occasional irrigation.

Albizia brevifolia ( Rock Albizia )
A broadly-rounded, medium-sized, deciduous tree that is native to southern Africa. It thrives in the U.S. in southwest Arizona and southern inland California with only occasional irrigation. Some records include: 2 years - 8 feet; 3 years - 13 feet; 6 years - 16 feet; 7 years - 20 feet; 11 years - 26 feet; maximum size - 35 x 50 feet ( estimated ).
The bipinnate leaves resemble that of A. julibrissin but is blue-green.
The creamy-white flowers are borne on puffy rounded clusters.
They are followed by pods up to 11 inches in length.
The stems are typically spine-tipped.
Hardy zones 10 ( est ).

Albizia chinensis ( Chinese Silk Tree )
A spreading, very large, rare tree to 60 feet, native to India and southwest China. Some records include: fastest growth rate - 2 inch increase in trunk diameter;
1.5 years - 15.5 feet with a trunk diameter of 1.6 inches; largest on record is 142 x 100 feet with a trunk diameter of 5 feet.
Compared to Albizia julibrissin but is stronger wooded, has rougher bark and creamy white flowers. It also has much less delicate looking foliage; its leaves being composed of only up to 16 leaflets which are up to 1.3 x 0.7 inches in size. The foliage is deep green.
Hardy zones 7 to 10 ( further testing of all seed source required for true determination ).

Albizia coreana ( Korean Silk Tree )
. A medium size tree with a maximum size of 60 x 40 feet ( largest known tree in U.S. so far is 37 feet in Raleigh, N.C. ).
The showy, powder-puff flowers are yellowish-white and it blooms 10 days before similar Albizia julibrissin.
The leaflets are much larger than A. julibrissin. The foliage is bright green.
Hardy zones 6 to 9 ( possibly 5b on protected sites ). It is very drought tolerant.

Albizia coriaria
A slow growing but large flat crowned tree with often twisted branches, reaching a maximum size of 120 x 100 feet. It is native to Africa.
The bipinnate leaves are composed of oval leaflets up to 1.5 x 0.5 inches.
The bark is gray-black, scaly bark.
Hardy zones 9 to 10.

Albizia ferruginea
A huge tree with a beautiful spreading crown that is native to western Africa.
It can reach a maximum size of 155 feet with a trunk diameter of 4 feet.

Albizia harveyi ( Sickle-leaved Albizia )
An attracive, moderate growing, flat-crowned or rounded, medium-sized, deciduous tree, reaching up to 50 x 50 feet in height, that is native to southern Africa where it is rare. It thrives in the U.S. only in southwest Arizona and with occasional irrigation. Some records include: 2 years - 6 feet; 3 years - 8 feet; 5 years - 11 feet; 7 years - 14 feet; 10 years - 18 feet; 12 years - 22 feet.
The bipinnate leaves are bright green.
The creamy-white, fluffy flowers are followed by flattened pods up to 7 inches in length.
The attractive, deeply furrowed bark is gray-brown.
Hardy zones 10 to 11 ( est ).

* recommended link
https://www.inaturalist.org/taxa/340162-Albizia-harveyi

Albizia julibrissin ( Mimosa Silk Tree, Pink Siris )
A fast growing, flat crowned tree, up to 40 feet or more, native to western Asia as well as Japan. Some records include: fastest recorded growth rate - 8 feet; 3rd year - 20 feet; 24 years - 75 x 70 feet with a trunk diameter of 2.6 feet; largest on record - 75 x 103 feet with a trunk diameter of 5 feet; largest in PA - 67 x 77 feet in Philadelphia; largest in Maryland - 70 x 82 x 3 feet in Baltimore.
The feathery, bipinnate, compound leaves are to 20 x 9 ( rarely over 12 ) inches in size. The pointed, smooth-edged, narrow leaflets are up to 0.5 inches long. The leaflets fold up at night. The foliage is deep green above, pale green to whitish beneath; turning to yellow or often just a lighter green during autumn.
The abundant, fluffy, pink, "powder puff" flower inflorescences, up to 2 inches across, are held above the foliage, during mid-summer. The flowers are loved by hummingbirds which feed on the nectar.
They are followed by pods, up to 8 x 2 inches in size, that often persist through winter.
The stout twigs are green at first later turning red-brown.
The thin bark is coarse textured and gray though not ridged. Stems have no thorns.
Hardy zones 6 or 7 to 12 ( see below for 'Tyrone' which is more cold hardy )
Prefers a warm, deep, well drained soil in full sun on a site sheltered from excessive wind. They are best planted directly from seed or when very small; it is important to protect the taproot when transplanting.
Seedlings usually reach 4 feet in the second year and sometimes much larger.
Tolerant of drought, high soil PH and salt. Very heat tolerant, it actually requires hot summers to thrive. Pruning is often needed when young to force the growth upward since the tree has a tendency to spread. Mimosa webworm and vascular wilt disease may be a problem in some areas.

* photos taken on June 15 2010 in Ellicott City, MD









* photos taken on July 15 2013 in Columbia, MD

* photo taken on July 13 2014 in Columbia, MD

* photos taken on July 15 2015 in Columbia, MD

* photos taken on June 24 2016 in Columbia, MD

* photos taken on Nov 4 2019 in Columbia, MD

* photo taken on Oct 22 2020 in Columbia, MD

* photos taken on July 13 2022 in Columbia, MD

* photos taken on July 19 2024 in Columbia, MD

'Charlotte'
Similiar to species but considered to have superior resistance to Mimosa Wilt making it a choice selection for the southeast.

'Chocolate Fountain'
A weepeing form, reaching up to 10 x 6.5 feet in 2 years, eventually up to 20 x 15 feet.
The foliage is purple.
Hardy zones 7 to 10

'E.H. Wilson'
Exceptionally hardy, tolerating as low as -15 F or slightly more. It may survive as low as -24 F, however with substantial stem damage and may need to be cut to near ground during early spring.
It may be the same as var 'Rosea' which originated in Soeul, South Korea.

* photos taken on July 25 2015 @ Niagara-on-the-Lake, Ontario

* photo taken on July 5 2022 in Windsor, ON

* photo taken on Aug 14 2024 @ Coventry Gardens, Windsor, ON

'Fine Wine'
Similar to 'Summer Chocolate' except that it is typically grown on its own roots rather than grafted. The foliage is deep red during spring, turning to red-bronze during summer. It retains its color better than 'Summer Chocolate' in extreme heat.

* photo taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

'Flame'
bright red flowers.

'Summer Chocolate'
Foliage is light green in spring before turning to deep purple in summer. Many plants of this cultivar, retain the purple foliage when grown from seed.

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







* photos taken on October 17 2010 @ U.S. National Arboretum, D.C.



* photo taken on June 25 2017 in Howard Co., MD

'Tryon'
Superior resistance to Mimosa Wilt disease and hardier, north to zone 5 on protected sites and with winter dieback.
The flowers are deeper pink than species.

'Umbrella'
Fast growing with very dark green foliage.
Dark pink flowers.

Albizia kalkora ( Kalkora Mimosa )
A fast growing, stately potential street tree native to India and China that can reach up to 50 x 60 feet with a trunk diameter of 2.5 feet. Indeed one almost that large grows in North Carolina despite this tree being extremely rare in the U.S. It is similar to Albizia julibrissin except with white flowers.
Hardy zones 6 to 9

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



* photos taken on Aug 30 2021 @ U.S. National Arboretum, Washington, DC

* photos taken on Oct 23 2024 @ U.S. National Arboretum, Wash, DC

Albizia lebbeck ( White Siris )
Native to tropical Africa, southern Asia and Australia; this is a very fast growing, large flat topped tree reaching 100 feet or more. Some records include; fastest growth tate - 9 feet with trunk diameter increase of 3 inches; 21 months - 15 feet with a trunk diameter of 2 inches; 3 years - 25 feet; 10 years - 60 feet with a trunk diameter of 26 feet; largest on record - 120 x 100 feet with a trunk diameter of 10 feet.
The leathery pinnate leaves are up to 16 x 9 inches in size and are composed of leaflets up to 2 x 1 inch.
The late spring flowers are greenish, "powderpuffs".
Long, thin pods containing many seed follow the flowers. These rattle in the wind.
The timber is valued for cabinetwork and is attractively figured.
Very drought and salt tolerant.
Hardy zones 9 to 12 tolerating as low as 15 F

* historic archive photo

Albizia lophantha ( Cape Leeuwin Wattle )
Also called Albizia distachya. A very fast growing, semi-evergreen small tree native to Indonesia and naturalized in western Australia and in South Africa where it has become a weed. Some records include: first summer - 12 feet; 2 years - 8 inch trunk diameter; largest on record - 50 x 40 feet.
The bipinnate leaves up to 12 x 11 inches in size are composed of many leaflets up to 0.3 inches. The fine-textured foliage is luxuriant mid-green.
The abundant small creamy-white flowers are borne in axilliary spikes up to 4 inches long in spring.
They are followed by abundant, long, flat brown pods, up to 3 x 0.3 inches in size, that carry many black seeds. The pods ripen summer to autumn.
Hardy zones 9 to 10 as a tree, requiring full sun and well drained soil. It prefers hot summers. Tolerates 0 F as a perennial if sheltered. Trees may uproot in very high winds.
Very difficult to transplant but also very easy to grow from seed; multiple plants should be sown on permanent site with the most vigorous seedling kept in place.

* historic archive photo

Albizia molucanna
A tropical member of the Albizia family that is also the worlds fastest growing tree. Some records include: fastest recorded growth rate - 20 feet per year; 10 years - 100 feet; largest on record - 130 feet

Albizia procera ( Forest Siris )
A tropical legume that is also one of the worlds fastest growing trees. Some records include: 6 years - 55 feet with a trunk diameter of 1.6 feet; 12 years - 70 feet; 17 years - 90 feet with a trunk diameter of 3.3 feet; 30 years - trunk diameter of 6.6 feet; largest on record - 120 feet with a trunk diameter of 6.6 feet.
The feathery bipinnate foliage is large, up to 18 x 20 inches. The foliage is luxuriant deep green.
Hardy zones 10 to 12

Albizia samam ( Monkeypod Tree )
A large tree to 150 feet with a broad spreading crown that is native to the wet tropics from Central America to Brazil. Fast growing, some records include: 110 years - 10 foot trunk diameter; largest on record - 200 x 250 feet with a trunk diameter of 10 feet!
Yes you read that right; this tree is HUGE!!!
This tree is sometimes grown to shade Coffee and Cacao crops.
The bipinnate leaves are composed of downy leaflets up to 1.5 inches long.
The flowers are fluffy white "powderpuffs"
The flowers are followed by seed pods which are edible and often used to feed livestock.
The timber is very valuable and is used for furniture manufacture.
Hardy only in the tropics from zone 10 to 12.

* historic archive photos

Albizia sinaloensis ( Sinaloan Silk Tree )
A rapid-growing, very handsome, medium-sized tree native to north central Mexico that reaches up to 50 x 20 feet or more. Some records include: largest on record - 70 x 30 feet.
The evergreen foliage is up to 9 inches in length. The foliage is mid-green, turning to yellow before falling during the dry season.
The flowers are white.
Hardy zones 8b to 10 ( freezes to base at 16 F but resprouts vigorously ). Drought & urban tolerant. Thrives in Tucson, Arizona.
Easy to grow.

Albizia tanganyicensis ( Paperbark Albizia )
A very attractive, medium-size tree with a high, open crown that is native to the plateaus of eastern Africa from South Africa north to Tanzania. The maximum size of the Paperbark Albizia is 45 x 30 feet.
The very attractive bark is papery and cream colored, peeling off in large sheets that turn indian red, to reveal light green new bark.
The foliage is deciduous. The leaves up to 12 inches in length are composed of leaflets up to 1.5 x 1 inch in size.
The sweetly fragrant, white, "powder puff" flowerheads appear on the bare branches in late spring and early summer.
The flowers are followed in early summer by flat, purplish brown pods up to 12 inches in length.
Hardy zones 9 to 11

Albizia zygia ( Brown Mimosa )
A very fast growing, spreading tree with a graceful architectural form which grows huge. Some records include: 6 years - 45 feet with a trunk diameter of 7 inches; 17 years - 82 feet in height; largest on record - 120 x 100 feet with a trunk diameter of 9 feet.
The leaflets are up to 3 x 2 inches.
The bark is smooth and gray.
A tropical tree, hardy zones 10 to 12