How to Grow a Willow Hybrid
A willow hybrid is a cross between two different species of willows or their cultivars. These willows are crossed because a willow hybrid can be stronger than its parents, plus it can have the best traits of both of the willows. It can also develop some new plant variation for the first time such as different colored leaves or disease or pest resistance. Usually a hybrid is hardier than either of its parents.
You need to go all the way back to the 1880s in Germany to find the first willow hybrid. In fact, one of the first, Golden Weeping Willow, can still be obtained to this day. Over the years since then, hybridization among willows has been a common practice and one of the characteristics most desired in the hybrids was fast-growing. A willow hybrid is crossed to make continually faster-growing hybrids to control erosion, protect privacy or serve as windbreaks.
Most of these types of hybrid willows are white willows, or hybrids of Salix alba. You can purchase several of these hybrids that grow 6 to 10 feet every year. All of this growth happens in the first five years of life and by the time the willow is seven years old it is fully grown. They are very upright with very close-growing branches, not with spread-out branches like other kinds of willows.
Another willow hybrid is very well-known and that is the hybrid weeping willows. These trees do have more horizontal branches but because they weep, they drop down towards the ground. A willow hybrid can grow anywhere from thirty-five to seventy-five feet tall and they have a life of twenty to forty years.
Weeping willows are very popular as they are fast growing as well. And you really can’t kill a willow. It grows in just about every soil type and it doesn’t mind if it is in the sun or shade. They do prefer moist soil to dry and if you have a severe drought, you might need to water your willow hybrid. Be sure to cover the ground with three to four inches of an organic mulch to keep in all the moisture you can.
If you purchase a willow or several, here are some planting guidelines:
Make a hole twice as wide and deep as the willow tree rootball. Fill in the hole with organic fertilizer and compost until it is only as deep as one rootball. Then place the willow in the center of the hole. Hold it steady and fill in the area around the rootball with dirt you removed. Make sure the top of the rootball is at the surface level. You can use your foot to pack the soil around the tree.
Plant your willows three to four feet apart if you are using them as a windbreak or for a privacy hedge. A hybrid willow can be invasive and it is on the invasive plant list in some states. Willow plants are either male or female. Hybrid willows are supposed to be sold only as sterile males. But sometimes the tree you buy turns out to be a fertile male tree. This tree can cross with species willows and spread far and wide.
You also need to prune willows. Sometimes a hybrid willow grows suckers and if these suckers are not removed, eventually what you will have is a massive thicket that spreads across and beyond your property. Keep in mind that if your willow trees have catkins, they are fertile male trees and not sterile male trees.
A hybrid willow can grow in just about any location, warm or cold. Before you plant them, however, give some thought to their drawbacks as well as their advantages. Certainly, a hybrid willow is a beautiful, fast-growing tree. It can also be invasive. It can grow roots far underground that can tangle with water and septic lines so you need to be careful of placement. And, because it grows so fast, it can have weak crotches, where the branches attach to the trunk. This can lead to branches breaking and falling onto power lines, cars and houses in the event of high winds or an ice storm. In this way they are similar to the Bradford pear tree.
A willow hybrid can have some very good qualities, but make sure you have lots of room for them to grow and that you are prepared to take care of them so they don’t run wild.