Nothing announces the arrival of spring quite like the willows (Salix) at the Arnold Arboretum. Willow species are most at home in moist to swampy conditions. Hence, the core of the willow collection can be found around and in the wet meadow between Willow Path and Meadow Road. Prepare to get your feet wet and take in some of these willows while they are close to their peak of flowering.
Willows are dioecious, with individual plants bearing either male (pollen-producing) or female (seed-producing) flowers. These unisexual flowers are “reduced,” with no sepals or petals, and are borne in catkins, a type of inflorescence distinguished by large numbers of flowers in a compact arrangement. The male catkins conjure up a fireworks show, with beautiful yellow to orange to red anthers (pollen sacs) that then split open to display bright yellow pollen inside.
Pictured below are the pollen-bearing catkins of Salix udensis ‘sekka’ (Japanese fantail willow; 671-67*A; image here) and Salix gracilistyla (rosegold pussy willow; 930-74*A; image here), and a close-up of a female catkin of Salix cinerea (gray willow; 60-95*B; image here) showing the gaping maws of two-parted stigmas of the flowers. Our willow sex ratio at the Arnold is skewed, with many more pollen-bearing plants than seed-bearing plants. Could this be evidence of horticultural gender bias?