Snow And Cold Can Be Both Harmful And Helpful To Your Garden

I am not a big fan of cold or snow. For most of the winter you l can find me within feet of the wood stove marveling at the beauty of the season but staying well beyond its touch. I prefer to enjoy winter from the inside. But both the cold and the snow play an important part in our gardens and both can have immediate effects and long term ramifications on the garden in the warmer months to come.

Some of the effects of winter are subtle and nearly invisible. Under the snow cover, winter annual weeds like corn speedwell, henbit and chickweed are growing at the soil surface just waiting for a mild day to flower and set seed then die in the spring leaving seed behind that germinates in the fall and then grows again in the winter. They’re close to impossible to control but if you see them in garden beds or around fruit trees during a thaw that’s the time to pick or hoe them.

Then there are the insects of winter. The most fascinating is called the snow flea. These are not really fleas, but small springtails that kids usually find as the snow melts. They jump about looking for organic matter to eat and are perfectly harmless. Snow fleas are most noticeable when there’s about an inch or less of snow left with some turf or soil peeking through.

Cold effects plant growth and plant hardiness. Many fruit trees such as apples need a certain number of hours of cold or chilling to set buds that result in flowers that ultimately produce apples. As I’ve noted in other columns it’s not simply how cold it gets, but how cold it gets for how long and how deep that cold gets into the ground. As it gets colder and if the cold becomes persistent it penetrates deeper and deeper into the ground to what we refer to as the frost level or frost line. As the frost line drops it has a more and more dramatic effect on plant roots. In most cases a tree or perennial’s hardiness is related to its ability to withstand severe cold for a certain amount of time and to a certain depth.

There’s a phenomenon called heaving that we don’t often have to deal with out here but it does happen. Frost heaving is what happens when the ground freezes then warms and thaws repeatedly causing the soil mass to expand and contract, effecting the smaller soil particles to larger clods of soil. This expansion and contraction from repeated freezing and thawing can cause the soil to “heave,” resulting in protruding mounds of soil not related to moles and their sub-surface digging. The heaving is most dangerous to plants that might have been planted late in the season such as small shrubs, perennials and even some bulbs. The heaving can literally push them out of the ground severing the roots and exposing the crowns leaving them unprotected from the cold and subject to desiccation and drying out.

You can ameliorate the potential for heaving by applying a winter mulch. This is a mulch that goes on certain garden areas that might be subject to freezing and thawing. It’s mostly likely to occur in a spot that faces south or in a garden bed that’s fully exposed to the sun. Obviously snow cover insulates the soil and keeps it below or near freezing, but when the snow begins to melt a winter mulch can keep the sun and even warmer air temperatures from causing a thaw and thus limiting the potential effects of heaving. So here, the snow is great.

Snow is actually a great insulator and it stabilizes the soil temperature. But there’s a lot going on in that small space between the snow and the ground. Below the snow and under the winter mulch the voles are busy gnawing away at fruit trees and shrubs just at the soil level and when they can they’ll dig to get at the crowns and roots of many perennials. To limit their damage you should never apply a winter mulch within several inches of the trunk of a tree or shrub and keep the mulch as thin as possible around perennials keeping the sun off the soil but not leaving enough mulch for the voles to hide under.

Winter brings other issues. I was astonished last week when we had one of the coldest mornings of this winter. I took the dog out for walk just before the sunrise and there near my fenced in Japanese maples was a very large rabbit looking for something to munch on. The dog wanted to get into hot pursuit but I thought better of that with the snow cover and it being just shy of 10 degrees. But I was happy to see that the sod staples that I’d installed at the bottom of the C-Flex deer fencing around the maples was indeed keeping the fencing tight to the ground so the rabbit couldn’t crawl under and get to the maple’s stems. So, at least up to now, one small victory.

A few minutes later on the other side of the house a grey squirrel was busy drilling down through the snow occasionally taking a break to look around for a possible predator, then back to the digging. Using its uncanny memory or stash radar, the squirrel persistently dug until it found a buried black walnut, which it promptly curried away with. That incident reminded me of the day we took the Christmas tree out of the barn and brought it into the house for decoration. These strange things began to drop out of the tree though … pre-ornaments. It seems that the red squirrels that winter in the barn had decided that the Christmas tree was there for the winter and they had stashed their own cache of walnuts in the tightly corseted tree. So of course the minute we began to cut the plastic corset from the tree the nuts began to fall. Startled and confused, the two humans paused and had a good laugh.

Within days of setting my winter seed boxes outside there was close to a foot of snow on the ground. Sure enough, on the surface of the snow, there was a set of foot prints leading from a wooded area 30 feet away making a beeline for the boxes. The prints were easily identified as those from a mouse and the mouse was out-moussed. The mesh covers that I had on all three of the seed boxes keep them safe and the mouse undoubtedly frustrated as its tracks led right back to the woods. If you see animal tracks in the snow and your curious to know what critters are leaving the behind you can start by downloading this guide to animal tracks in the snow from the DEC: www.dec.ny.gov/docs/administration_pdf/tracks1.pdf. You should be able to find 11 of the 16 on most East End properties. Keep growing.