How to Plant and Grow Willow

Willows are known to be majestic, moisture-loving trees and shrubs. But not all willows are big—they come in different shapes, colors, and sizes, making them a popular choice for planting in landscapes and even for container growing. These tough trees, some native to the United States, are dioecious, meaning male and female flowers are borne on separate male and female trees, so they rely on wind pollination. The attractive flowering catkins appear in April or May; they produce large amounts of pollen and have many exposed pollen-receptive parts. 

The leaves on a willow are narrow, lance-shaped, finely toothed, and are most often light green on top with a gray-green underside. During the fall, willows usually have a greenish-yellow color. In winter, the thin stems and smooth bark offer winter landscape interest.

Where to Plant Willow

Willows like moisture and slightly acidic to neutral soil. They are best grown in or around ponds, streams, and other bodies of water, so their roots have easy access to water. Not all willows are as tall and wide as weeping willows, which reach 50 feet in height and width. Regardless of the mature size of the variety, they should be planted with care, as their roots will grow and damage underground utilities, such as sewers and power lines if planted too nearby. Also, keep in mind that planting below a willow and mowing around it can be difficult.

How and When to Plant Willow

Plant your willow in the fall, about six weeks before the first expected frost. Measure the distance to any underground utility lines (also keep in mind those of your neighbors) and mark your planting location at least 50 feet away from them.

Dig a hole as deep as the root ball and twice as wide. Place the tree in the center of the hole and backfill it with the original soil. Tamp down the soil, water it well and continue to water the tree weekly in the absence of rain.

Willow Care Tips

 Light

To give a willow optimum growing conditions, plant it in full sun.

 Soil and Water

Willows should be planted in medium-to-wet, well-drained soil that is slightly acidic to neutral (5.5 to 7). Because of their love of water, they are often not drought-tolerant. In extremely dry situations, willows tend to be stunted and grow very slowly. 

Temperature and Humidity

There are many different types of willows, and their temperature tolerance varies depending on the type, but generally, they are very winter-hardy trees or shrubs. Some varieties can be grown even in climates with subzero winters; however, they are not tolerant of extremely hot or humid climates and aren’t suitable for growing above zone 8.

Fertilizer

Generally, willows don't need fertilizer. However, if your willow isn't looking healthy—for example, the leaves are pale instead of green—apply a slow-release complete granular fertilizer in the spring, according to product label instructions.

Pruning

Because willows are fast-growing trees, they need regular pruning. Start the pruning routine—in the late winter or early spring when the tree is dormant—when the willow is still young, as this helps it grow into a more vigorous tree. Remove all dead, diseased, and damaged branches and all additional stems growing from the base. Also, remove branches that cross and could rub against each other, weakening them. The goal of pruning is not merely aesthetic but also to improve air circulation and get light into the canopy.

Pruning a young weeping willow differs from willows with an upright growth habit. Identify the leader and handle it carefully; do not ever prune it. Also, leave all the horizontal branches intact. Remove any branches that grow from the main trunk in a V-angle, as these are prone to breaking.

Potting and Repotting Willow

Dwarf or miniature weeping willow trees can be grown in containers. However, they require large and heavy pots, at least 2 feet in diameter and 30 inches tall, to accommodate the tree's extensive root system. Since the potted tree is hardy and should remain outdoors year-round, select a weatherproof container that does not crack in freezing temperatures. It should also have large drainage holes.

Fill the container with equal parts potting mix and aged compost. Container plants, especially moisture-loving willows, need more frequent watering than plants in the landscape. Having a drip irrigation system set up is useful for keeping up with the watering. Also, feed with a slow-release complete granular fertilizer in the spring and a couple of times during the growing season until late summer.

When the roots have filled the pot, it's time to repot the willow in a larger pot, at least 6 inches larger in diameter than the old pot, and fresh potting mix and compost.

Pests and Problems 

Willows may be susceptible to blight, powdery mildew, leaf spot, and cankers. They may also face pest problems like aphids, scale, borers, lacebugs, and caterpillars. Because these trees grow rather fast, the wood is often weak and tends to crack. It often sustains damage in storms or when burdened by winter ice and snow. Leaf litter and scattered branches after windy weather are also potential problems.

How to Propagate Willow

Willows are one of the easiest trees to propagate from cuttings. While it can be done any time of the year, spring is the best time, as the sapling has time to grow as much as possible before the winter. Take a 10-inch, healthy-looking cutting about the diameter of a pencil. Remove all but the top pair of leaves from the cutting. Either place it in a tall jar with water or push it deep into a 1-quart pot filled with damp potting mix so that only about 2 inches of the cutting are above the soil, Keep it well-watered at all times in a location with bright light but away from direct sunlight.

When the cutting has developed a good set of roots (in potted cuttings, you can tell by gently tugging on it), you can plant the willow in the landscape.

Types of Willow

American Pussy Willow

Salix discolor is an American native pussy willow. This variety can be quite large, up to 20 feet tall, depending on the variety, and is grown for its fuzzy silver catkins in spring. Zones 4-8

Black Pussy Willow

Salix gracilistyla 'Melanostachys' is noted for its deep purple-black catkins in spring that make excellent cut flowers and look stunning on the 6- to 10-foot shrub. Zones 5-7

Dappled Willow

Salix integra 'Hakuro-nishiki' is one of the boldest shrubby willows, offering strongly pink- and white-variegated new growth. It's a vigorous grower that can reach 8 feet tall and wide. Zones 5-7

Dwarf Arctic Willow

Salix purpurea 'Nana' offers delightful blue-green foliage and a compact habit that makes it ideal for a low hedge. It grows 3 feet tall and 5 feet wide, though it is sometimes grafted onto a standard as a small tree. Zones 4-7

Japanese Creeping Willow

Salix reticulata is an unusual groundcover shrub offering dark green leaves that are silver and fuzzy on the bottoms. It grows 3 inches tall and 12 inches wide. Zones 2-6