Sex and the Single Salix: Considerations for Riparian Restoration

Abstract

Most restoration projects strive to create a sustainable plant community but exclusive use of vegetatively propagated material may be preventing this goal. The dioecious wil- lows and cottonwoods of the Salicaceae are widely used in riparian restoration projects. Hardwood cuttings have traditionally been used to propagate these species in nur- series, and live stakes, branched cuttings, and poles are also used in bioengineering structures for bank stabilization. Woody cuttings are collected either from the project site or from stooling beds in nurseries during the winter dormant period. Unfortunately, little attention has been given to the sex of the donor plants. The potential problem is that a proper mixture of male and female plants may not be present in the hardwood cuttings or rooted cuttings destined for the restoration site—in the worst case they may be entirely 1 sex or the other. Fortunately, it is relatively easy to distinguish male and female plants. Collecting cuttings from many different plants and from a known ratio of males and females will ensure that the resultant plants will be able to produce viable seeds and achieve the ultimate goal of a sustainable plant community.