What happens when landscapes ‘go dormant’?

After a successful planting of some native plants in my garden earlier this summer, I decided to take another plunge this fall in buying a few more in early October. I visited one of the well-known native plant nurseries in our area – Landscape Alternatives – to get some ideas and potentially some plants.

While I’ve heard much about how it’s a great idea to plant native plants in the fall, it definitely goes against my gardening intuition (of what little there is!). Meeting Roy at Landscape Alternatives, however, was amazing. He was so knowledgeable and patient with my questions – the biggest one being whether it really was a good time to plant.

His answer:

“These plants know how to handle our climate. You plant them now, and they’ll still have several weeks to spread their roots before they go dormant for the winter.”

I had my mom with me on my visit to Landscape Alternatives…

That conversation, which by the by led to the purchase of a fair share number of plants later that day, really started making me think about the concept of ‘dormancy.’ When I think of winter, I think of trees with no leaves and hibernating bears. I think of deer and rabbits that come to feed on the bark of my shrubs because other food sources are scarce. But I’ve never actually really thought of the process of how the greater landscape ‘goes dormant,’ or ‘goes to sleep.”

That thought process was further piqued a couple weeks later during my family’s last camping trip to Interstate State Park in Taylor’s Falls. At the visitor’s center, a Minnesota DNR representative had set out an “I Spy” type activity where visitors were challenged to find frogs in pictures of fallen brown leaves and brush. The frogs were quite tough to find, and while we strained our eyeballs, the DNR educator talked about how frogs survive winter in our Minnesota climate.

Essentially, as temperatures drop, the frog will find a hiding spot – either digging a spot below the frost line or finding a crevice or hole to overwinter in – and its liver will start mass-producing glucose (sugars) that helps prevent ice formation in the frog’s body. A partially-frozen or frozen frog will stop breathing and its heart will even stop beating, but the glucose works as an anti-freeze that inhibits damage to the frog’s organs.

Up to 70% of the water in a frog can be frozen and it can still survive through to the spring.

That’s a pretty amazing adaptation.

The American toad is one native Minnesota frog species that burrows deeper into the ground below the frost line for winter.

And surprisingly (or perhaps unsurprisingly?), perennial plants use a similar mechanism to go dormant in the off season as well. Shorter days, changing angles of incoming sunlight, and drops in temperature serve as triggers to the plant to slow respiration and photosynthesis. Water circulation slows and stops with freezing temperatures. Plant foliage (leaves, flowers) shrivel and die away and sugars and carbohydrates produced by the plant in the growing season are then moved to and stored in the roots. These resources serve as ‘anti-freeze’ against ice formation in the plant cells during winter temperature fluctuations. While the top inches of soil may freeze, soil temperatures remain much more consistent and moderate underground than the open air environment, protecting plant roots. Having a layer of mulch and snow can provide the soil and plant roots further insulation from extreme temperatures.

I will fully admit that after I planted my crop of native plants in early October, I enjoyed thinking of them taking a few weeks, even with temperatures close to freezing at night, to stretch their roots underground and entrench themselves in the soil in preparation for the oncoming winter. I didn’t see any new growth above ground, but I wasn’t supposed to – all the effort would be going on where I couldn’t see it.

Yes, this is a bean plant, but the root growth coupled with the awesome soundtrack? Totally what’s been in my head when I think about my native plants doing their thing.

One other shift I’ve noticed in my perception as I’ve learned more on the topic: I’ve generally thought of winter being immensely stressful for our landscapes and ecosystems (probably because it’s stressful on ME!), but winter dormancy is actually more about rest and restoration for these landscapes. It’s a survival mechanism, yes, but all those good sugars that plants and many creatures store and utilize for the winter are also what’s used to break dormancy in the spring. Winter is a time to hang back, re-group, and get ready for another growing season.

As we’ve started experiencing our first snowstorms and below freezing temperatures of the season in the past couple weeks, I find myself watching the landscape with more appreciative eyes as it tucks itself in for the winter. And I’m already excited to see what will come up next spring as the longer hours of sunlight and warmer temperatures start to shake the landscape back awake.

All tucked in for the long winter’s nap.