The effects of late cold snaps

There’s a joke in Kentucky that goes something like this, “If you don’t like the weather just wait a day”.

Yesterday I worked outside in a t-shirt and got hot (and a sunburn!) This morning I’m wearing my winter coat and hat! While most of the time, it’s just a blip to our fashion choices, these weather fluctuations can be harmful.

Specifically I’m referring to cold snaps we’ve had in mid to late springtime in 2020, and now 2021.

In Kentucky and other regions of the US, May of 2020, we had several periods of heavy frost and freezing temperatures. Flash forward to last night, April 21 2121, we received a good amount of accumulated snow with temperatures just below freezing.

Our average last FROST date is technically April 15th. Much less freezing temperatures in May, or snow accumulations in late April. Who knows what else is yet to come this spring.

What happens when it freezes and snows in late spring and how is this detrimental to the ecology, farming, the nursery and landscaping trade, and beloved garden plants?

Chokeberry 2 Days Ago
Chokeberries Now

Ecology

While most plants are likely to bounce back just fine, some species will take a hit.

Some native spring flowering plants will likely loose their flowers and won’t develop seed pods. In an already struggling environment of habitat loss and invasive plants, this could influence populations of spring wildflowers. Thankfully, many are probably insulated by the forest canopy and leaf litter on the forest floor. So, in an insulated forest environment they are hopefully well protected.

If fruiting plants are in flower, and their flowers are damaged, they may not set fruit. Including nut trees. This could affect how much food is available for birds and wildflower later this year.

We can learn form this! Leave leaf litter and wait to clean up the garden as late as possible. This will give plants insulation during these unpredicted cold snaps.

The wood poppies may not form seed pods. The phlox flowers will probably fade while usually they last weeks.

Trees Specifically

In the case of late snow, trees and shrubs can be easily damaged this time of year. There is a reason trees and shrubs loose their leaves in winter. If trees have leaves in high winds, there is a higher chance that tree can be damaged or fall down. The same with snow. If trees have leafed out and we receive snow, there is more weight on the tree and a higher chance of it being damaged.

My nine bark is nearly completely leafed out, and looks quite droopy.

Farming

Late frosts and freezes is just one nightmare for farmers. Many fruit trees and shrubs bloom early in the season. If those flowers are damaged, they cannot develop, and they cannot form fruit. The plants then really struggle to produce any fruit at all. This in turn creates shortage, raises prices in the grocery store, and quality is compromised. No telling how this affects the farmer. The same goes with any planted crop that cannot take the late freeze or frost.

Nursery Trade

In May of 2020 and last night, I saw my local nurseries posting on social media about covering up plants. They showed rows of nursery plants covered up in swaths of horticultural fleece. Last year due to the several late freezes in May, the Japanese Maples at the nursery took a hit. They did not look their prime the rest of the year and I wonder if sales declined due to this.

While most shrubs were probably okay, perennials, herbs, and vegetables can quickly perish in frosts or freezes. In addition, these plants are grown in greenhouses to get a head start, so they’re very acclimated to the nice cushiony temperatures and environment they were grown in. They’re already trying to adapt to being outside, much less a frost or freeze.

Many nurseries do not have greenhouses. If they do, they may not be at the retail location. It’s probably virtually impossible to transport plants back to a greenhouse considering the sheer number of plants, staff, space, and the last minute forecasts.

Landscaping Trade

The freezes in May last year made my business more aware of planting client’s gardens too early. This year, I’ve been quite apprehensive to start too much planting, especially perennials. The last thing I want to do, is plant a client’s garden full of perennials, and we get a late snow or freeze. It would not be a good position to be in!

To plant or not to plant? That is the question. Landscaping businesses can suffer the loss of income either way they decide. Plants may perish if planted too early and we get a late freeze or snow. It questions who is responsible. If they replace plants, it’s a loss. Push projects later into the season, and the work season shortens, which may mean taking on less projects.

Landscaping companies already have short time frames to work within a year (unless they do hardscaping, snow removal for example). Planting season around Kentucky is about a 6-7 month timeframe at most. Late freezes, rainy days, temperatures over 90 degrees, and early freezes all shorten that season to maybe 4-5 months.

Covering up a bunch of plants can be tedious!

Beloved Garden Plants

Plants are very resilient. I was amazed how well plants did with the several late freezes in May 2020. The tender leaves on my fringe tree and buttonbush, froze off 3 times! While they barely flowered last year, the leaves grew back like new.

While I think most plants do just fine, some will not fair well.

It’s always sad to see flowers go earlier than they should. My tulips are likely done for. The tender petals on some native wildflowers will probably drop. Some plants may have the tips of their stems scalded. Many plants could be set back or show damage the rest of the year, but they will likely live on.

If the plant is already suffering, a freeze can do it in. My mom had a yellowwood tree that was making it, but not thriving. They are difficult trees to establish. The freeze sadly did it in last year. A friend just had a Japanese maple planted. There was phythophthora root rot in the soil, which causes a slow decline in plants. Also sadly, the freeze secured its final fate.

I forgot to cover my blueberries last night. I wonder if the flowers were damaged; will they form fruit this year?

I covered up my onion transplants and hope my seeds trying to germinate faired well.

I wonder how well my hostas did…

Last year, I could not plant some of my vegetables until very late in the year. I didn’t get tomato seeds planted until June. I barely got any tomatoes last year. What is a home vegetable gardener to do? For me, it means starting them inside early and waiting. Growing them up larger before planting will take more work.

Conclusion

While most plants can go through a late freeze, frost, or snow just fine, some will not. This will affect wildlife and the economy in several different ways. These impacts can be large and severe, especially on agriculture. I have never seen freeze and frost this late in the spring as I have these past 2 years. Will this be a common trend? This may affect how we landscape our backyards.

Choosing native plants that are more resilient to frost and freeze will be more important. My native columbine was barely scathed.

Every gardener should have some horticultural fleece on hand and items to secure it down to the ground.

A little drooped over, but columbine is so hardy!