Don’t Toss the Tree!

With the Christmas season coming to a close the site of evergreen trees lying at the curb awaiting pick-up is now a common sight in urban areas. Before adding yours to the mix, take a look at your garden first. Evergreen boughs are a great way to protect tender perennials or even small shrubs from winter damage! So read on! Your tree may just serve another purpose beyond decorating your home for the holidays.

The Problem

Most perennials and small shrubs can survive the winter unscathed. There are a few, however that are thankful for extra protection- especially when it comes to preventing desiccation (drying out). Plants that tend to suffer the most from this type of winter damage include those in the evergreen or semi-evergreen categories. The problem lies in the fact that plants are still able to lose water from their leaves during the winter months (drawn out by sunny warm temperatures as well as wind) yet plants are not able to replace this moisture because it is locked in the soil in the form of ice. Broadleaf evergreens tend to suffer the most because, rather than needles that remain green all winter, these plants have leaves which means there is a much larger surface area from which water can escape the plant. Often a good blanket of snow can provide the protection that these more sensitive plants require, but in areas with unreliable snowfall and frequent warm winter days, these plants can look quite ragged by the time spring rolls around.

The Solution

Enter the use of evergreen boughs. By placing branches on top of tender plants, the plants are protected from water loss (and therefore desiccation) in a couple ways:

1. Plants are shielded from the sun- this can help prevent the warming of foliage and subsequent stimulation of metabolic activity (which ultimately leads to water loss)

2. Air flow around the plants is reduced- therefore water that is drawn out from the leaves by wind is reduced

3. The boughs can capture snow and therefore promote natural protection in the way of snow cover (this is an especially useful technique for plants that are considered marginally hardy, as the snow not only protects from sun and wind but it also helps insulate the plants from temperature swings thereby protecting them from the full brunt of winter’s frigid temperatures or unseasonably warm days).

Helleborus spp. (left) a broadleaf evergreen that can look a little ratty come spring if situated in an exposed location; the same plant with pine boughs placed on top to provide some winter protection for the plant (right).

And there you have it, a brief discussion of one winter plant protection strategy. If you have already tossed your tree… don’t worry! Use this as an excuse to meet some new neighbours. How could you not strike up a conversation when you start it by saying “hey, do you mind if I trim your tree?”

Happy New Year and happy (January) gardening!