According to the forecast for this weekend, on both Christmas day and Boxing day temperatures may drop to between -7 and – 10 degrees Celsius, with snow expected as well. There are some simple things that can be done to protect your tender plants from the cold.
Broadleaf evergreens (plants that keep their leaves all winter but are not conifers) are generally more sensitive to cold than deciduous plants (which lose their leaves in winter) and conifers (which usually have needle- or scale-like foliage). Many broadleaf evergreens are well adapted to our typical winter conditions, but New Zealand flax, Mexican mock orange, Cordylines, “hardy” bananas, Hebe, hardy gardenia, pittosporum and eucalyptus are a few of the most popular broadleaf evergreens that will benefit from extra protection.
On the West Coast, we can’t resist tender perennials and bulbs, and are willing give them a try, treating them as annuals, knowing that they may not survive a harsh winter. Giving them a little extra protection will improve the odds that they will make it through! Examples include both Canna and Calla lilies, tender sages like ‘Amistad’ and ‘Hot Lips’, some fuchsia varieties and maybe even Osteospermums!
Tropical and tropical like plants that we especially love to grow in containers include Lantana, Abutilon, Majesty Palm, Mandevilla vines and Hibiscus. All are best brought in to protected locations in early fall and will not survive a winter outdoors.
If you have tender plants in your garden, here are some tips to protect them:
- Mulch the roots with 2-4” of bark mulch, coco coir (e.g. Mega Mulch), leaves, evergreen boughs, or straw. This helps trap heat released from the soil. If you have tender bulbs planted, this is especially important to ensure their survival. A layer of snow is also a great insulator, if it arrives on the scene ahead of the coldest temperatures!
- Crop cover (thick insulating fabric) laid out over plants will help trap heat and keep the foliage a few degrees warmer than the surrounding air. It also prevents moisture loss through the leaves, while still allowing penetration of some light and water.
- A wind break structure erected around your vulnerable plants will prevent the wind from drawing moisture from the leaves (the cause of winter burn). Simply place several stakes around the perimeter of your plant, and wrap burlap around them up to the full height of the plant. Click here for a how-to video!
- Water your plants well before a cold spell. Water frozen in the soil is unavailable to the plant, so watering ahead of time ensures that plants are well hydrated and less likely to suffer winter burn damage or dessication.
- Protect plants in containers by either bringing them close to the house and wrapping the pots with an insulating material (generous layers of blankets, burlap, or even bubble wrap). Alternatively, false plant containers in a hole in the ground and mulch thoroughly. In both cases, drape a crop cover over the foliage so it is protected as well. If you have exceptionally tender plants in containers, bring them either indoors, or in an unheated garage.
- Heavy snow has the potential to accumulate in the canopy of broadleaf evergreens and some conifers, like cedar hedging, resulting in broken branches or a severely damaged hedge. Be prepared to knock snow off these kind of plants before it begins to accumulate.
As always, if you have questions, drop by your favourite GARDENWORKS location and our resident experts will be happy to give you more guidance.