Fall is one of my favorite times of the year with the vibrant foliage colors, delicious rich food and cool crisp mornings; it is also a busy time at my farm and nursery. Winter plant care, or packing up the nursery, as I like to call it reaps mountains of rewards in the spring. Many of you have asked me how do I overwinter plants in my garden, and plants in my nursery. Hopefully this post will answer many of your questions.
When preparing my farm for winter I mentally sort plants into two categories; plants that require little winter care and those that are more finicky for my climate zone.
Winter Plant Care at My Nursery:
Typically any plant which is two USDA hardiness zones or lower from the gardening zone that you are located in, is good to go with little winter care other than good overwintering practices. At my nursery located in a zone 5 this includes:
- Own root roses that are growing in pots larger than 14 inches in diameter will overwinter outside with little winter care. Smaller roses need more nurturing and would appreciate a greenhouse or cold frame for protection. The same goes for any 4 inch perennial plant or grass. Soil mass is a wonderful insulation and small potted plants just do not have enough soil to keep them happy over the winter.
- Hardy shrubs and native plants. The back of my farm is covered in Ponderosa pines, Mahonia (Oregon Grape), Larch and other native shrubs and trees therefore I adopt the mantra of if its living outside naturally then don’t worry about it.
- Most perennials that are hardy to zone 5 excluding potted Iris which like to be dry in the winter with their shoulders above the soil. My Irises that grow in raise beds or in the perennial gardens thrive in cold winters.
A little side note here: soil tilth has a lot to do with overwintering success. Always grow your plants in nice, airy soil that drains well. Compacted soil will tend to cause plants to sit in water in the spring as the snow melts resulting in root rot.
- Small fruits which are cold hardy to zone 5 such as blueberry, raspberry and strawberry plants that haven’t been planted in the garden still like the cold, wet winters and prefer to be left outside. But I do store my prized potted blueberry plants in a low tunnel to keep heavy snow from breaking their branches.
Winter Plant Care Protection:
- For plants that are left outside, I rack them in rows or blocks on plastic pallets in a full sun location. Why plastic pallets? Because the pallets keep the pots off of the ground which is typically 5 degrees colder than the air temperature. In addition I can slip a little rodent bait under the plants if needed, and in the spring the plants thaw much quicker. The pallets at our farm work great in allowing us to pick them up with a Bobcat and move them around without much effort.
- Plants requiring protection from winter winds and snow load are trimmed back and placed in non-heated low tunnels. Plants in the low tunnels are watered every week until late November at which point I let them go completely dormant. I cover my low tunnels in either clear plastic or white plastic depending on the plants in side. The plants in the low tunnels break dormancy about 4-6 weeks earlier than the plants outside.