Willow

Willows are renowned for being extremely fast growing, tenacious, and adaptable. They prefer moist locations and range from tiny, cute little shrubs to extremely large trees. Most are very hardy. Prairie gardeners have many that they can choose from.

The sharp-leaf willow (Salix acutifolia) is from cold places in Europe and Asia. It has long been grown on the prairies as a shelterbelt and a windbreak. It is a very fast growing tree with reddish colored new growth, dark bark, and usually yellow fall color. It has better drought tolerance than most willows but would very much prefer to be grown in places where moisture conditions are good. It reaches a mature size of 16-25 ft. and nearly as wide.

‘Blue Streak’ is a good cultivar that has pale blue coloring on the twigs of the new growth. This species hybridizes very freely and much of what is now being sold as sharp-leaf willow is actually of hybrid origin.

The silver willow (Salix alba) is also called the white willow (a reference to the wood). It’s been used extensively in willow hybridizing programs. Found throughout cold parts of Europe, Asia and high altitudes in north Africa, it is a rapid grower that can reach 75-100 ft, although 50 ft. is more average. This is a dense, billowy tree with blue-gray or green-gray foliage that has a soft and silky texture. It is extremely beautiful and very hardy, but is not commonly grown. It does not fare well in chinook zones, but has been planted in many places across the prairies both for shade and as a shelterbelt, though it does require moisture. There are a number of naturally occurring variations of this species, and they can be found in the nursery trade.

Salix alba var. sericea is a Siberian selection that is a bit smaller and slower growing than the species, as well as being more silvery. It also has better drought tolerance than the species and is less prone to littering. Salix alba var. vitellina is often called the golden willow. It has brilliant, golden-yellow twigs that are at their most showy in late winter and early spring. It grows quickly into a large tree, usually about 50 or 60 ft. tall at maturity and up to 40 or 50 ft. wide! Fall color of the leaves is also showy (bright yellow) and in moist places on the prairies, it has been used as a shelterbelt and for shade.

Weeping willows are iconic trees, and easily recognized by even people who aren’t gardeners. Despite the name, the weeping willow (Salix babylonica) is not actually native to Babylon, but rather, China. It is an extremely rapid growing tree that reaches 30-50 ft. tall, and up to 60 ft. wide. There are a number of cultivars of this tree, and it is often hybridized with Salix alba. (These cultivars are usually listed as Salix x sepulcralis).  If you must find fault with a weeping willow, most prairie gardeners bemoan the fact that they just aren’t prairie hardy- zone 5 is pretty much the limit of their cold tolerance.

What can you do if you really want a weeping willow but you live in a cold climate? Well, there are two selections that are worth investigating.

‘Prairie Cascade’ is a hybrid introduction from the Morden Research Station in Manitoba. It grows about 30 ft. tall and wide, has brilliant golden stems, and as it ages, it develops a graceful, semi-weeping habit. Trials with this variety across the prairies have been mixed- it will often grow well for anywhere from four to six years and then suddenly experience extremely significant dieback. It does recover very rapidly, but this can be extremely annoying if it’s already a decent sized tree when this happens.

‘Northern Fountains’ is a very distinctly weeping form that was selected from the golden willow. (S. alba var. vitellina) It has the same brilliant yellow bark and is extremely showy. It grows 20-30 ft. tall and wide and although not widely grown, it is worth investigating.

Finally, the laurel-leaf willow (Salix pentandra) is perhaps the most widely planted willow on the prairies. It is a rapid growing species magnificent as a shade or shelterbelt tree. Native to cold parts of Europe and Asia, it has naturalized in North America. It reaches anywhere from 20-60 ft. in height and just as wide, with deeply furrowed grey-brown bark and yellow-green twigs and branches. The long, lustrous leaves are a very deep green and usually turn bright yellow in the fall.

Laurel leaf willows are exceptionally hardy but they also drink exceptional amounts of water and are prone to dropping significant quantities of twigs and branches, particularly after a wind storm. If you plant one, expect to be raking a lot! It is also extremely difficult to garden under or near a laurel leaf willow- they will suck every last drop of moisture out of the soil. That said, they are an outstanding tree in the right place. They are not prone to suckering unless the roots are disturbed, so be careful about rototilling or digging near them.