Pussy Willows on Parade

After a long winter, the humming of bees around velvety sprays of willow inflorescences signifies new life in the landscape – the pussy willow. Children have a special affection for the soft, furry catkins that appear overnight, as the buds that have grown fatter each sunny day finally burst from their hoodlike scales. For many of us the memory of a pussy willow tree in the back yard is the strongest early childhood horticultural experience.
    
For northern temperate zones the flowering of pussy willows coincides with the Easter season. In eastern Europe, where true palm leaves are difficult to obtain, willow branches decorate the churches on Palm Sunday, and dried willow twigs are blessed by priests and taken into homes as a symbol of protection from adversities of nature.
    
Yet, pussy willows have somehow become old-fashioned – perhaps because the traditional varieties were such large shrubs. These days, pussy willows seldom appear in residential garden plans. This is a real shame because these plants are fast-growing, tolerant of poor soils and urban conditions, relatively care-free, and among the earliest flowers in the garden – even preceding most spring bulbs. The bright stems and polished buds of some willow shrubs offer attractive winter color, while other species can be forced into bloom beginning in January. Pussy willows are integral to the goal of having something to pick from the garden, year-round.

A Closer Look at a Catkin

Flower buds containing the furry catkins, or inflorescences, form during the preceding year, and their development continues throughout the winter until they expand enough to push off a bud scale. At this stage the inflorescences are very dense, consisting of tightly grouped individual flowers subtended by bracts with dense hairs that determine the color of the catkin – silver, gray, green, pink or even black.  
    
Willows are dioecious woody plants, having male or female inflorescences borne on separate plants. Male catkins are typically showier than the females, displaying dramatic pollen colors with the anthers ranging from deep red to yellow and orange. As spring progresses, catkins elongate, losing their velvety density. Blooms normally drop off the branch soon after anthesis, or when filaments become visible.
    
After flowering, some willows turn into ordinary green shrubs and their beauty fades away until next year. Others have attractive or unique foliage, texture or stem color making them excellent foundation plants for garden structure.  But even the short and glorious early spring display warrants the addition of these plants to the garden.
    
Timing and duration of flowering vary considerably among the species. The earliest to release its inflorescences at the end of January is Salix schwerinii, followed by S. aegyptiaca, S. koriyanagi, S. gracilistyla and S. acutifolia.
    
At the end of February, S. gracilistyla ‘Melanostachys’ (also listed as S. gracilistyla var. melanostachys) and S. ‘The Hague’ continue the spectacular catkins display. Later in March, S. caprea and S. discolor are followed by the late S. hookeriana and S. x friesiana. Though all cottony inflorescences are guaranteed to flower despite the harshest of late winters, the floral display of some species – such as S. koriyanagi and S. gracilistyla –  can last as long as four weeks  if the weather stays cool.  
    
For maximum catkin production, shrub willows should be coppiced or pruned back hard each year or two. The best time to prune those willows that bloom before leafing out, including the species discussed here, is soon after they have flowered. The plant benefits significantly from pruning, and it helps turn the shrub into an attractively full specimen. Hard pruning also helps to maintain a willow’s appropriate height and  promotes straighter branches that produce numerous flower buds suitable for floral arrangements.  Annual coppicing of stems further stimulates growth if plants have been affected by disease.
    
Not all species of willows have inflorescences with the characteristic “pussy” effect. From over 150 willow taxa we have collected and observed at the Chadwick Arboretum of the Ohio State University at Columbus, we selected the following species and cultivars that appear to have the most exquisite catkins. Willow species differ markedly in size, density, and shape of their inflorescences, as well as in bloom time.  The following are some of the most highly recommended species and cultivars.

Royal Among Pussy Willows

Salix ’The Hague’ is a vigorous female cultivar of hybrid origin; its parents are S. gracilistyla and S. caprea. Big bronze buds resembling shiny beetles are very prominent before opening. Its light gray catkins reach almost 2 inches long at maturity are the largest of all pussy willows. The plant grows 6 feet to 8 feet tall with a 4-to 6-foot-wide spread.
    
Salix acutifolia (sharp-leaf willow) is a small tree from Eastern Europe that reaches approximately 13 feet to 20 feet tall. In the residential garden it should be pruned to limit height. Its light gray, large catkins measure three-quarters of an inch long and are more widely spaced than other species. However, the plant’s elegant, purple branches covered with white blooms make this species worthy of inclusion.
    
Salix aegyptiaca (Armenian willow or musk willow) is one of the earliest species to flower. It has thick, rigid, green stems, and its gray catkins reach about three-quarters of an inch long.  The multidirectional hairs of flower bracts give the catkins a nappy appearance. The species grows 25 feet tall and 10 feet wide, and it should be used in large areas such as parks and cemeteries.
    
Salix caprea (goat pussy willow) offers a very prolific catkin display in spring, featuring pink-gray catkins that measure half an inch long. Reaching 20 feet tall and 10 feet wide, this vigorous Eurasian species may be better suited for large landscapes. A few clones are circulating in the trade that may do well when space is limited. One of them, S. caprea ‘Pendula’, is most suitable for small residential gardens when grafted onto 31/4 to 5-foot stock. This miniature pussy willow makes a handsome container plant to be admired on a patio in early spring.
    
Salix gracilistyla (rosegold pussy willow) is an Asian species native to Japan, Korea and China. It has very soft and shiny, large, uniform, light gray catkins reaching 1 inch to 1 3/8 inches long and half an inch wide. The bright flower buds are conspicuous all winter, adding to the plant’s ornamental appeal. It is an attractive, graceful shrub in summer as well, growing to 6 feet to 9 feet tall and 6 feet wide.
    
Salix gracilistyla ‘Melanostachys’ (‘Melanostachys’ Japanese pussy willow) is a very unusual cultivar with dramatic-looking, three-quarter-inch-long, black catkins and brick-red anthers. Less vigorous than the species, this selection reaches 4 feet to 7 feet tall with a 5-foot spread.
    
Salix koriyanagi is a Korean species with flexible stems and abundant crops of dark gray catkins that measure three-quarters of an inch long.  This easy-to-cultivate plant reaches 10 feet tall and 5 feet wide, and it looks attractive in summertime by virtue of its dynamic branches gracefully moving in the slightest breeze. The leaf arrangement is rather unusual for willows, as they grow in pairs up the stem.
    
Salix schwerinii is another Asian species with the small gray catkins, measuring just under a quarter inch long that can be used as seasonal filler for spring bouquets. This species is the earliest to bloom and grows 10 feet tall with a 5-foot spread.

A few species native to North America also have distinguished catkin displays:
     
S. discolor (pussy willow) is common throughout moist forest edges and is probably the most popular species in our landscape, though other species may be superior in catkin display. This small tree reaches almost 10 feet to 15 feet tall and 5 feet wide in the wild, with gray catkins about half an inch long.  
    
S. hookeriana (Hooker’s willow or dune willow) is a Western species with  white, miniature, “cotton swab” catkins reaching 1 inch to 1 ½ inches long. It grows up to 10 feet tall and 5 feet wide.
    
S. humilis (prairie willow) is  a good alternative where space is limited. Along with S. schwerinii, it has the smallest catkin. They are dark gray and also reach just under a quarter inch long. This species grows 5 feet to 7 feet tall and wide.  
    
For most of us, it’s easy to look back on a childhood memory involving pussy willows. But not many children today can treasure such an experience, as the use of these fine trees and shrubs has diminished in the landscape over the years. By incorporating the plants into designs we can bring more beauty to the garden and offer new memories as well.

Figures:
Figure 1. With their dense hairs, the soft catkins of Salix caprea look cozy even on a cold winter day. (p. 4)
Figure 2. All attention is focused on the many catkins of S. ‘The Hague’, which blooms before foliage emerges. (p. 4)
Figure 3. Dramatic pollen colors are displayed by the male flowers of  S. gracilistyla ‘Melanostachys’. (p. 4)                                                        Figure 4. White sprays of willow inflorescences stand out against an evergreen background. 
Figure 5. For S. humilis, actual time of anthesis, when filaments become visible, lasts for only a few days.