Pussy Willows (genus Salix) Make Early Showing

Observation by Mike Brubaker:

The willows are blooming on the Southside of our lot. I have seen the early appearance of pussy willows before, sometimes even earlier when we have had mid-winter thaws. But as far as ‘normal’ timing, the willows, air temperatures, and spring in general seem to be arriving about a month early. Two weeks of warm weather and our snow, along with our winter, nearly gone.

Katie Spellman, Ecologist at the UAF International Arctic Research Center, writes:

Hi Mike, I just responded to Jimmy Evak in Kotzebue about this too, and the Cooperative Extension folks forwarded me your message since I love all things plant phenology!

Some species of willows are very sensitive to spring temperatures. Here where I grew up in Interior Alaska, Salix alaxensis (feltleaf willow) is the very first flowering plant to pop its buds when the temperatures warm up, even when snow still remains on the ground! In some international warming chamber experiments on tundra willows across the Arctic, the warmer spring temperatures made some species of willow flower earlier, but not all (Jones et al. 2003). I checked out what I could find on reports of Salix flowering in Alaska. I found other reports of flowering of Salix alexensis in May 30 – June 10 in Atkasook (Williams and Batzli 1982), and May through June on the UAF campus (West and Salo 1979). At Toolik Field Station on the North Slope, they have monitored Salix pulchra for 12 years, and the earliest they have recorded it flowering was May 22 (in 2016 and 2017). March is early for most parts of Alaska! I also learned that the fuzz on the catkins (those soft white hairs) can actually trap heat, and keep the bud warmer than the air temperature when the sun is not hitting it (Krog 1955)! This is good news, because early flowering puts plants at a greater risk of frost damage. The pussy willow fuzz adds protection from that risk. The bad news is, if the buds have popped open and ptarmigan haven’t come through yet, they lose out on some of the nutrition of the buds (mostly lipids) which are spent by the willow plant developing the catkin. Timing is everything!

Comments from LEO Editors:

Anchorage Daily News reports that March 2019 was the likely warmest on record for Alaska. Rick Thoman, climate scientist at the Alaska Center for Climate Assessment and Policy, tweeted a map of statewide temperature departures from normal. Anchorage reached approximately 9 degrees above normal. In a similar post this month, observer Jimmy Evak, reported that willows were also budding early in Kotzebue, where temperatures were nearly 22 degrees above normal. Erica Lujan