Albizia julibrissin 'Summer Chocolate'

Updated: Aug 19


Summer is here, and I love chocolate, so let's dive right into a tree that does not receive too much attention. Meet the velvety chocolate descendent of Albizia julibrissin with its deep purple to burgundy leaflets that make the pink puffy flowers pop in summer. Its coloring was first noticed in 1990 when Dr. Masato Yokoi noticed a seedling singing, "I gotta be me!" with its unique coloring among its green brethren, as I loosely interpret from the U.S. Patent. Yes, plants are patented now, because horticulture science creates new plants all the time, and like musicians, their creators want to maintain rights of ownership. It has become a sensitive issue, because unscrupulous people will take plants home, propagate them, and resale them under different names in an attempt to make a buck. Champagne versus sparkling wine kind of thing...sort of.


Summer chocolate silk tree was patented by Hines Nursery, Inc., who holds patents on several species. For our purposes, summer chocolate does not reach the same size as its parent, but that might be debatable, since several websites describe its size anywhere from 20' to 40' tall. Their growth habit is similar, too, with horizontal branching causing beautiful layering, similar to larger Japanese maples. Minor pruning maintains an attractive silhouette.


For California designers, A. julibrissin 'Summer Chocolate' presents an opportunity to migrate away from the ubiquitous purple-leaf plums seen in too many commercial developments where they struggle under extended droughts or even insect invasions like the tussock moth. This purple-leafed silk tree is considerably more drought tolerant while still producing pink blooms. Of course, there is that size question; anything more than 20' and it will be larger than the purple-leaf plums. Their different overall form and texture should also be taken into consideration. Still, if purple leaves are desired as a contrast to green, this is a noteworthy option to withstand California's climate.

facts

Botanical Name: Albizia julibrissin 'Summer Chocolate'

Albizia: Honoree, 18th century naturalist, Filippo degli Albizzi

Julibrissin: Persian, gul-ebruschin, for floss silk (referencing the delicate flower appearance)

Common Name: Summer chocolate silk tree; purple-leaf mimosa

Family Name: Sapindaceae


Origin: Iran to Japan


design considerations


Positioning: Lawn, riparian (may lead to reseeding), patio, street, slope, forest edge

Garden Themes: Asian, Mediterranean, desert, pollinator, woodland

Uses: Shade tree, specimen, street, accent, foliage contrast


identifying characteristics


Type: Deciduous tree (multi-trunk or standard)

Form: Vase, umbrella, spreading (with horizontal branching)

Texture: Fine

Size: 20' wide x 20' tall (may become larger with age)


Outstanding Feature(s): Flowers, foliage, shade value


Bark: Dark gray and smooth

Leaf:

  • Type: Bi-pinnately compound

  • Arrangement: Alternate

  • Shape: Elliptical to oval (leaflets are oblong, from 10-25 pinnules; 50-60 leaflets)

  • Margin: Entire

  • Color: Light green as new leaves unfurl turning deep purple above, bright burgundy underneath at maturity. Little to no fall color value.

  • Surface: Smooth

Flower: Summer. Puffs of stamens, white to pink in apical clusters. Fragrant (close range)

Fruit: Autumn into winter or longer. Legume, deep brown


cultural requirements, tolerances & problems


Sunset Zones: 4-23

USDA Zones: 6-9


Light: Full sun to part shade

WUCOLS SF Bay Area Hydro Zone: Low

Soil:

  • Texture: Sand, loam, clay, chalk

  • Moisture Retention: May dry between watering

  • pH: Highly acidic to highly alkaline

Tolerances: Drought, heat, poor soils, saline

Problems: Considered short-lived elsewhere

  • Branch Strength: Medium to weak

  • Insects: Borers, aphids

  • Disease: Armillaria, fusarium, root rot

citations & attributions


Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.


Hines Nursery, Inc. "Albizia julibrissin tree named 'Summer Chocolate'." JUSTIA Patents. Accessed on July 2, 2021 from https://patents.justia.com/patent/PP13822.


Missouri Botanical Garden. "Albizia julibrissin 'Summer Chocolate'." Accessed on July 2, 2021 from https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=293062&isprofile=0&.


Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.


NC State Extension. "Albizia julibrissin." North Carolina State University, Raleigh. Accessed on July 1, 2021 from https://plants.ces.ncsu.edu/plants/albizia-julibrissin/.


RHS. "Albizia julibrissin 'Summer Chocolate'." Royal Horticulture Society, London. Accessed on July 2, 2021 from https://www.rhs.org.uk/plants/258154/albizia-julibrissin-summer-chocolate-pbr/details.


Urban Forest Ecosystems Institute SelecTree. "Albizia julibrissin Tree Record." 1995-2021. Cal Poly State University, San Luis Obispo. Accessed on July 1, 2021 from https://selectree.calpoly.edu/tree-detail/147.


Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on June 28, 2021 from https://ucanr.edu/sites/WUCOLS/Download_WUCOLS_IV_List/.


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