Salix humboldtiana

Mature Size, Growth, Longevity

Can grow to a 40-60', or up to 80' tree under ideal conditions. Has a narrow-triangular / pyramidal or columnar crown shape, with an open canopy and pendulous branches. Other times, grows as a large, multi-stemmed shrub. Willows tend to have a relatively short longevity due to various insect and disease problems and weak branches that break in storms.

Native Range

Native from Central Mexico into Central & South America, to southern Chile and Argentina, growing along streams and rivers, in areas with tropical, subtropical and temperate climate, from near sea level to heights of up to nearly 11,000 feet of elevation.

Flower and Fruit Details

Flowers are catkins, 1.5-3.5" long. Male flowers are yellowish-green, with a bract and 6 stamens, Female flowers are green. Some reports say it very seldom flowers in the wild, where it is often found growing in waterways of South America and Australia Fruit is a capsule, not showy.

Leaf and Bark Features

Deciduous: Leaves are narrow, lanceolate, serrated, light green, up to 6" long. Yellow fall foliage color. The tree develops dark brown to gray, fissured bark. Younger bark is gray, and new twigs are green to golden.

Culture and Care

Requires consistently moist soil. Hardy from Zones 5-10. In the far South, partial shade is beneficial during hot summers. Mulch or keep near water. Susceptible to numerous disease problems, including blights, powdery mildew, leaf spots, and cankers. Insect pests include aphids, scale, borers, lacebugs and caterpillars.

Strengths, Weaknesses, Other Facts

May become aggressive in its growth in waterways, especially in the far South, based on its behavior in South America and Australia. Listed in the Global Invasive Species Database as an invasive plant in some parts of the world, including Anguilla, Puerto Rico, and Virgin Islands, U.S. It is considered a potential or emerging environmental weed in New South Wales.

Suggested Uses

May be used as a living screen or hedge, or in stream restoration projects. Grown in Costa Rica and Panama for use in basket making, and in Cuba as a living fence.

Taxa and Plants of this Species at BCA

The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.

  • Salix humboldtiana 'Pyramidalis' // Chilean Pencil Willow
    Shrub. May be grown as a shrub or tree. Usually grows as a tall, slender tree, often used for screening along fence lines and driveways. It is cultivated as an ornamental. Flowers are catkins, 1.5-3.5" long. Male flowers are yellowish-green, with a bract and 6 stamens, Female flowers are green. Leaves are narrow, with finely-toothed margins. Good yellow fall foliage color. It has become naturalized along waterways in warmer parts of Australia.
    -- not currently in our collection --