The willows that line Colorado’s waterways are a unique and important plant in our high mountain wetlands. They are a vital food source for wildlife, provide shelter for riparian creatures, and their roots secure the soil to prevent erosion and to filter pollutants from the water before it reaches our rivers and streams. There are between 300 and 500 species of willows worldwide and the salicylic acid they produce has been used as a pain killer and anti-inflammatory since at least 1500 BC. It was given to Alexander the Great on his deathbed and eventually led to the development of aspirin and other NSAIDs that many people rely on to manage pain and inflammation today.
First Sign of Spring
Willows are important not only to humans, but also to other animals and the marsh ecosystems they inhabit. While willows may appear lackluster, their furry little buds, or catkins, are one of the first signs that spring has arrived. These catkins that give “pussy willows” their common name (they look like fuzzy feline toes) serves a purpose similar to that of a cat’s fur. Willows are also unique in that they are dioecious, meaning that individual plants produce only male or female flowers. Unlike most dioecious plants, willows are not wind pollinated. Instead, willow catkins produce strong olfactory cues to draw bees and flies in to ensure pollination. The species of flying insects that emerge early in spring face many of the challenges willow buds themselves do. It is cold, days are still relatively short and food sources for insects are scarce. This means that many flying insects whose life-cycles are timed for an early spring emergence rely on willow nectar for food.
While serving as an important food source for some of the tiny insects who emerge in the month of March, willow catkins appear on the menu for some of the largest animals in Colorado as well. Moose, who were introduced to Colorado in the 1970s, wander and wallow through willow marshes all year long. The scarcity of food still makes winter a challenging time for animals with such large bodies and high energy demands, and the emergence of willow catkins comes as a welcome relief from the stress of winter for moose as well.
While the summer wildflowers are sure to be spectacular this year with their bright flowers and gaudy displays for pollinators, the first flowers you will see this spring are much subtler to the human eye. If winter is beginning to get you down and you are longing for a glimpse of life returning to the high country, then pull on some waders to explore the marshlands along a high mountain stream.
Pete Wadden is the field research educator at Walking Mountains Science Center. He looks forward to navigating the willow tangles and cursing the clouds of mosquitos that inhabit them while collecting stream data with the natural resource interns this summer.