I’m hoping you can help out our school with some gardening knowledge. We have just received a bunch of native Ontario species of trees and shrubs to plant including maples, oaks, birch, cedar and raspberries. They are all VERY young and small. It being the end November which would give them the best chance of winter survival:
a) pack in grow bags, but in a sheltered place next to a building, insulate with straw
b)plant them in the forever growing places on our school property
Any advice you can share would be greatly appreciated.
Chi Miigwetch (thank you in Ojibwe)
Thank you for contacting the Toronto Master Gardeners.
How exciting to be planning a garden space with native Ontario plants. The best time to plant birch, oak and maple trees is in the spring spring or fall, when the soil is moist and temperatures are cool. If planting in the fall, allow at least four to six weeks before the ground freezes to give the roots enough time to become established. On the other hand, early spring is the best time to plant your raspberries.
Not knowing your location, planting at the end of November will not allow enough time for the roots of your seedlings to become established before the winter freeze up. As a result, I suggest that you temporarily plant your trees in a spot where they will be protected from the worst of winter winds. The best way to do this is to bury the pots in the ground, making sure that the soil covers the top of the pot. You want to create conditions which will protect the roots, to ensure that they do not dry out and are protected from the freeze/thaw cycle. Make sure that you water well before freezeup. You could mulch the buried containers, or the young seedlings with sawdust, wood chips or leaves to insulate against freeze/thaw. Try and make sure that the mulch is not right next to the stem of the seedling as otherwise you will have created cozy conditions for any mice, rabbits etc. that might chose to nest under the mulch for the winter. Your greatest risks in wintering outdoors are the roots drying out, rodents and freezing/thawing. Taking steps to mitigate against these risk should let your seedlings survive and thrive outdoors throughout the winter..
When determining the forever homes for your seedlings there are a few things that you need to take into consideration. Birch trees are shalow rooted trees as a result chose a location where the soil remains cool and moist while exposing the canopy to ample sunlight (about 6 hours daily).
Maple trees are a versatile tree that can grow almost anywhere. They grow best in full sun or partial shade and well-drained soil. Maple Leaves Forever is an excellent website that provides all the information required in growing Maple trees.
Like maple trees oaks can grow in a variety of soils but so best when the soil is well rained. Oak trees have a massive root system and will become large trees much faster than you think, so picture the area a mature oak (and its root system) will occupy in 20 years.
Raspberries prefer rich, well-drained soil. A couple inches of compost mixed into the soil prior to planting will create a high quality planting site.
Lastely, you may be interested in Landscape Ontario’s Tree Planting Guide which gives invaluable information on site preparation, tree stabilization and post planting care as well as this article on protecting trees and shrubs in winter.
Hope this was helpful.
November 24, 2020