Weeping Willow Plant Profile

Salix babylonica produces active ingredient in aspirin

Weeping Willow
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The weeping willow is probably the most well known of the weeping trees. The willow tree produces salicylic acid, which was the model for our modern aspirin. In landscaping, it is great for use as a focal point and in areas that are moist. These specimens love water, so do not plant weeping willows near sewer, septic tanks, or water lines. If you do, there may be problems for those water sources.

The leaves of Salix babylonica are 3 to 6 inches long and lance-shaped. They turn yellow in the fall before dropping. The yellow catkins appear in spring. They are inconspicuous. The fruit is a 1/2 inch brown capsule. The bark is reddish-brown during the winter.

  • Botanical Name: Salix babylonica
  • Common Name: Weeping willows or Babylon willow
  • Plant Type: Deciduous perennial
  • Mature Size: 35 to 50 feet
  • Sun Exposure: Full sun
  • Soil Type: Rich and moist
  • Soil pH: Slightly acidic
  • Bloom Time: Late winter, spring
  • Flower Color: Yellow
  • Hardiness Zones: 4 to 10
  • Native Area: China

How to Grow Weeping Willows

Weeping willow trees work well in areas that are naturally quite moist. Weeping willow trees do tend to shed a lot of leaves and twigs, and the tree is brittle, so avoid planting them where falling branches can cause damage. Weeping willows are fast-growing trees, adding up to 10 feet per year when young. Their root systems are aggressive sometimes stretching wider than the tree is tall. Plan on this as a relatively short-term tree—they live on average for 30 years.

Light

Full sun and partial shade are best for this tree. It needs at least four hours of direct, unfiltered sunlight each day.

Soil

This tree is tolerant of a wide variety of well-draining soils and soil pH. It is salt tolerant, making it a good choice along streets and sidewalks. Although it prefers moist, slightly acidic soil, it grows well in alkaline, loamy, rich, sandy, and clay soils. It grows really near water but has some drought tolerance. If your soil is too alkaline, you can add some organic matter to the soil around weeping willow trees to help lower the pH, too. 

Water

Willows like standing water. The long, far-reaching root system can clear up troublesome spots in a landscape prone to pools, puddles, and floods. They also like to grow near ponds, streams, and lakes.

Temperature and Humidity

Weeping willows can handle the winter cold. The tree can also tolerate summer desert heat as long as there are ample greenery and water around.

Fertilizer

A mature weeping willow does not require fertilizer if it is planted in rich soil and its leaves are a healthy green or nearby lawns are fertilized regularly. However, you can supply fertilizer to support lush growth.

A balanced fertilizer with an equal ratio of nitrogen, phosphorus, and potassium (such as a 20-20-20 formula) is appropriate for a weeping willow. Nitrogen supports foliage growth on the tree's long, weeping branches. Phosphorus supports the growth of roots, stems, and flowers. Potassium encourages overall health. If you plan to use organic fertilizer, steer manure is a good choice. It is a balanced combination of the main nutrients nitrogen, phosphorus, and potassium. 

Propagating Weeping Willows

Propagation of Salix babylonica is through stem cuttings. Make sure the cuttings are at least two feet long. Cut at the base and take from mature weeping willows when the trees are dormant, meaning after leaves have fallen in autumn and temperatures are consistently below 32 degrees F at night. Cuttings can be placed directly into soil in late winter or early spring. Keep the soil moist throughout the growing season to allow the cutting to develop healthy roots.

Pruning

While the tree is young, prune it so that there is only one central leader. It should also be trained to have wide branch crotches to help prevent breakage, as the tree is somewhat brittle and can be susceptible to wind damage. It is a good idea to prune a weeping willow in February or March, snipping back all its branches. This will trigger the sprouting of new branches and will give the tree more vigor.

Common pests include the gypsy moth, caterpillars, scales, aphids, and borers. This tree may be affected by willow scab, crown gall, willow blight, black canker, fungi, cankers, leaf spot, tar spot, powdery mildew, rust, and root rot.

Varieties of Weeping Willows

Although this tree is the most common in landscapes, there are some related species you might consider:

  • Golden weeping willow: (S. alba "Tristis") has golden twigs. It grows in zones 3 through 10 to a height of 50 to 70 feet tall and wide. Its green leaves turn golden in fall, adding autumn interest.
  • Wisconsin weeping willow (S. babylonica x S. pentachdra) grows quickly to 30 to 40 feet tall and wide. For a weeping willow with even longer pendulous branches, try the cultivar "Elegantissima." Both types grow in zones 4 through 9.