Snow, Straw, and Survival: Thirty Years of Peony Hardiness Research in Interior Alaska

June 27, 2025

Categories: Starting a New Farm

I have conducted research on peonies at UAF for 30 years. The botanical garden in Fairbanks lost 100% of its peonies twice during those years, both to no snow and -30F temps. There is no doubt peonies would not be in the Interior if it weren’t for a min 6 inches of snowfall that does not melt.

Despite fairly reliable snowfall, the Georgeson BG mulches its peonies every year with straw. We have had late snows and mid Dec melts, but the peonies survive. Of course, cultivars vary in their hardiness so some peonies are going to die regardless of mulches, snow. 

Since the peony industry in Alaska started on 2004, many other locations have experienced conditions unlike the Interior. Two main scenarios have emerged for significant losses. First winter cold with no bud protection. This occurs when the large flower buds closest to the surface are killed because they are not protected by soil, snow and/or mulch. Killing temps occur at about 23F although that can vary with cultivar. In the worst case, the entire root dies from exposure, but often it’s only those big flower buds at the top that are killed. The roots, if they are hard, contain numerous buds buried lower down on the roots. They are dormant.

When the main flower buds are killed, these buds can begin to grow. HOWEVER, this growth can be fast or darned slow. Plants will produce small vegetative shoots from 2 weeks to a couple of years after the first damage. It is amazing how these roots can come back to life months even years later. After a bad winter, dig down to the roots. If they are hard, they might just resurrect from the living pieces with dormant buds. 

Second, the ground freezes solid for many inches. But in the middle of winter, they thaw. Deep soils are still frozen or you get surface glaciating, the result is roots are sitting in water for all or part of winter. They rot. If you dig up roots and they are mush- they are dead. Nothing will save them. 

SO, when planting peonies, make sure soils are well drained and will have somewhere for water to flow in winter to prevent rot. Everything from soil texture, slope, to ditching can make a difference. 

Most importantly, MULCH! Wait until the ground freezes, then add a mulch to keep the ground frozen and prevent thaw.

Alaskans are quite inventive when it comes to mulch: straw, leaves, spruce branches, sand/seaweed, seaweed plus leaves, construction blankets, and more. The biggest issue is preventing your mulch from blowing away. A grower in Wasilla used birch leaves secured with bird netting. Everyone will find their own solutions. Snow, of course, is the very best insulator, and piling it on peonies is great. If you get less than 6 inches of snow, mulch is critical even if snow melts in mid-winter. Peonies are worth the effort, right