Pacifica Irises in Snow

By Kathleen Sayce

Written February 17, 2014

I started growing Pacifica Iris more than fifteen years ago, when the West Coast was in a warmer, drier weather cycle, so it took several years for my plants to experience even a little snow. In the past few years, a few snow days each winter have been more common than not, so I can now report knowledgeably on what happens to Pacificas in the snow.

Iris chrysantha under light snowfall

First, some species in my garden, including Iris hartwegii ssp. australis, I thompsonii and I. tenax, normally go completely dormant. In warmer snow-free years, they may or may not brown down until February. It's not uncommon for all of these species to keep green leaves for most of the winter, and then in early March, suddenly the old battered but still greenish leaves vanish, and a few weeks later the small, stubby new leaves appear.

Now add snow to the mix, even just a few days, and wham, the leaves brown off, and the plants vanish from the surface.

The second group, of species, includes Iris innominata, I. chrysophylla and I. douglasiana, and also hybrids, hangs on and keeps some green leaves all winter long, though those leaves can look pretty battered, and many are browning off, by late February. Hybrid Pacificas are a mix of many species, largely from around the Bay Area of the central California coast and nearby mountains. These tend to have more I. douglasiana genes, which is a sturdy evergreen species with large leaves.

Iris 'Cape Ferrelo' under light snowfall.

So the hybrids stay evergreen, come snow, hail, ice storms or torrential rains.

These traits, evergreen leaves or not, and a tendency to go fully dormant in snow or not, have helped me sort out the likely genetics of Pacificas that may come to a gardener without a label, or with an erroneous one. I. douglasiana and I. innomnata have durable evergreen leaves; I. douglasiana leaves tend to be thicker, longer, and wider, while I. innominata leaves tend to be a very dark green, narrower, and shorter.

Seedling Pacifica Iris emerging from snow in the garden.

My I. hartwegii ssp. australis plants were grown from seeds collected by a SPCNI member, Richard Richards, who lives in southern California. The first winter they experienced snow, I sent Richard a photo to show the plants well buried in white stuff. He wrote back that there was a drought that winter in the San Bernardino Mtns, and these plants might be the happiest individuals of that species anywhere on the West Coast that year. This was the first year that I noticed just how differently Pacificas go dormant under snow.

Iris hartwegii ssp. australis emerging from snow cover. 

The last photo in this post is a Pacifica iris that was labeled I. innominata 'Burnt Sugar' when I bought it many years ago. The leaves are too wide and long to be solely I. innominata, which is the mostly likely species based on flower color. There's not a hint of dormancy when ice storms and snow arrive. This one has some I. douglasiana genes too. By the fairly narrow falls and standards, it is not too far from a yellow-flowered species selection, and is not a modern hybrid. ['Burnt Sugar' is not a registered name] Thanks to an industrious Steller Jay, the original tag, including source, is long gone.

Iris 'Burnt Sugar', an unregistered selection, in full flower. 

Knowing now how Pacifica species behave in snow, it's clear that 'Burnt Sugar' has both I. douglasiana and I. innominata genes, hence the lovely yellow color with red veining on a sturdy plant with dark green leaves, and no sign of dying back under snow. 

To learn more about these irises and others, visit SIGNA, the Species Iris Group of North America's website.