Learn how to sow seeds of shrubs, trees in the winter

If you’re looking to increase the number of trees and shrubs on your property and you’re up for a challenge, now is a great time to start new trees and shrubs from seeds. Yes, it’s an exercise in patience, but it brings big rewards for generations to come.

Winter sowing is a technique used to propagate certain trees and shrubs. It can be done with some other plants as well, including certain perennials and herbs. Winter sowing involves planting the seeds of these plants outdoors in the autumn or winter, instead of in the spring. The process mimics the natural timing for seed drop.

Many tree and shrub seeds require a period of cold to break dormancy and germinate. Known as stratification, this period of cold is often artificially induced by placing the seeds in a freezer or refrigerator before planting them, but when seeds are winter sown in colder climates, the appropriate stratification period happens naturally.

By sowing tree and shrub seeds in the winter, there’s no need to employ grow lights, seed starting equipment and other tools. Instead, you’re relying on Mother Nature to do the work.

The process doesn’t take up much time or space. You can sow several tree or shrub seeds in each pot and then tuck them away in a corner of the yard somewhere. Plus, the best time to do this gardening chore is when there’s little else on your gardening to-do list.

In addition, there’s no need to harden-off (or acclimate) seedlings grown using this method. Instead, they’re already growing outdoors where they’re exposed to their natural growing conditions right from the start.

And lastly, winter sown tree and shrub seeds germinate and grow at the appropriate time for their species. There’s no need to guess or count calendar days to encourage proper germination — in most cases, they’ll do it just fine on their own.

There are many different tree and shrub seeds you can start over the coming weeks. Look first to native species that grow well from seed; these are almost always good candidates for winter sowing. Seeds collected from a hybrid trees or shrubs may not result in a plant that’s identical to the parent. For the best results, stick to winter sowing seeds of straight species, instead of hybrids.

A few trees and shrubs that perform well when winter sown include:

Oaks, maples, hazelnuts, hickories, walnuts, holly, beech, ash, horse chestnut, red bud, tulip poplars, viburnums, elderberry, euonymus, serviceberry, elm, birch, honeylocust and even lilac.

To winter sow tree and shrub seeds, simply bury several tree or shrub seeds of the same variety in a labeled container filled with a 50/50 blend of potting soil and compost. Typically, a depth of one-and-a-half-times the height of the seed itself is best. Space the seeds a few inches apart. Water them in well and put the pot in a sheltered site, if possible.

Tree and shrub seeds do not typically need any extra insulation, though tossing a handful of straw or shredded leaves on top of the pot helps insulate the seeds.

Come spring, the seeds will germinate when they’re ready. The seedlings can then be separated and re-potted, or planted in the ground as soon as they reach a few inches in height.

If natural precipitation doesn’t occur, you’ll have to irrigate your pots occasionally throughout the winter, but don’t keep them overly wet or the seeds may rot.