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Products > Quillaja saponaria
Quillaja saponaria - Soapbark Tree

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Habit and Cultural Information
Category: Tree
Family: Rosaceae (Roses)
Origin: Chile (South America)
Evergreen: Yes
Flower Color: White
Bloomtime: Spring/Summer
Height: 25-40 feet
Width: 10-15 feet
Exposure: Full Sun
Summer Dry: Yes
Irrigation (H2O Info): Low Water Needs
Winter Hardiness: 20-25 F
Quillaja saponaria (Soapbark Tree) - A slender, upright evergreen tree growing to 30-45 ft. tall with pendulous branchlets. The bright green oval leathery leaves are 1-1 1/2 inches long and 1/2 to 3/4 inches wide with slightly toothed margins but nearly entire towards the leaf base. Cream-white star-shaped flowers, about 1/2 inch across are freely produced at the branch tips during May and June and are followed by the 3/4 inch wide 5 lobed pinwheel shaped fruit which is of leathery texture and matures in the fall. Plant in full sun, water deeply and infrequently - can withstand drought conditions but looks more lush when given occasional deep irrigation or when planted in an irrigated lawn. It is also tolerant to poor soils. Quillaja is reliably cold hardy into at least the low 20s F and some suggest as low as 10 F. It went through our December 1990 freeze without damage with short duration temperatures down to 18 F (Sunset suggests zones 8,9,13-24). Young plants tend to be bushy and need occasional pruning when young but eventually form narrow, almost columnar, trees that is ideal for narrow confines. Another usage is as a tall hedge. This forest tree from Chile, where it is found in dry, poor soils up 6,500 feet, is often called Soapbark as the bark is harvested to extract saponins and other foaming agents. The specific epithet is in reference to these compounds while the name Quillaja (pronounced "key - ya - ha") is from the indigenous Chilean name Quillai (pronounced "key ya hey"), a modification of the word 'quillean', meaning "to wash". This plant is also noted as good for attracting beneficial insects, attracting to the garden such insects such as lacewings, hoverflies, lady beetles and wasps. The plant was listed in Harry M. Butterfield's (1887-1970) unpublished manuscript Dates of Introduction of Trees and Shrubs To California as being introduced in San Francisco around 1878. In Peter Riedel's (1873-1954) Plants for Extra-Tropical Regions published in 1957 after Riedel's death, he too lists the introduction being made in San Francisco about 1878 but has the official entry by the Bureau of Plant Industry, a division of the U.S. Department of Agriculture, with the number BPI 26325-1909, indicating it was also introduced in 1909. Riedel notes that at the time he wrote the entry for this plant, likely in the early 1950s, there was a large tree at the east entry to the UC Berkeley campus that uncharacteristically had a broad canopy but that there were a number of younger trees in Santa Barbara that were upright and suitable for street trees. Now 60 years later we still find several fine specimens of this tree in Santa Barbara and it is from these trees that we have collected our seed and grown this plant since 1985.  The information on this page is based on our research that has been conducted in our nursery library and from online sources as well as from observations made of this plant as it grows in the nursery, in the nursery's garden, and in other gardens where it has been observed. We also incorporate comments received from others and always appreciate getting feedback of any kind from those who have additional information, particularly if this information is contrary to what we have written or includes additional cultural tips that might aid others in growing  Quillaja saponaria.