How to prepare your garden for winter

Just as a garden changes and evolves over time, so too has gardening wisdom. Winterizing a garden used to mean thoroughly removing every leaf, stem and spent bloom, so that a property was as neat as a pin. But science has taught us that there is a whole host of important activity that happens among those leaves, stems and blooms. So, today, a fall cleanup looks a lot different than it did even a decade ago. Rather than stuffing everything into yard bags, we're encouraged to leave a lot in place.

So what should your to-do list include? "Fall is a good time to re-evaluate, look at what worked, what didn't work and plan for next year," said Giuliana Casimirri, executive director of Green Venture, a not-for-profit environmental education organization based in Hamilton, Ont. "[Fall] is a great time to plant trees," she added.

So, what do you do with all those leaves?

"Leave the leaves" has become an important phrase, Casimirri said, pointing out that leaves feed biodiversity and support critters over the winter.

While we're encouraged to leave the leaves, there is a bit of a caveat. You can't leave thick mats of leaves on a lawn or they'll smother the grass underneath. Similarly, they're of no use forming a wet, soggy carpet over patio stones or a driveway. They need to be sent somewhere where they can decompose in peace. The solution? Rake them into perennial gardens where they'll break down over the winter, while providing shelter for beneficial insects. If you have extra leaves, you can save them in a compost bin for later use.

Fall is the perfect time of year to add a composter to the yard. That doesn't mean you suddenly need to start saving kitchen scraps. You can create compost simply from garden detritus, like leaves, grass clippings and twigs. And while it will take longer to break down, leaf mold, as the partially decomposed matter is known, adds valuable nutrients back into the soil. Not only is it beneficial to perennial garden beds, it's good for the veggie garden, too.

With a dearth of leaves in her urban garden, Casimirri will drive to neighbourhoods with large tree canopies on yard waste collection day, peek into a curbside bag to ensure it's all leaves, then bring them home to use in her garden. That should tell you how valuable they are!

Make a leaf smoothie

While mowing the leaves left on a lawn will chop them into a size that will decompose quicker, another tip from Casimirri is to make a "leaf smoothie." She'll place leaves into a garbage bin and use a weed trimmer like an immersion blender, moving it up and down to chop her leaves until they reach a sand-like consistency. These will be distributed in the garden to feed the soil. "They break down much faster, the soil is so much richer and I don't need to add anything after that," she explained.

A case for leaving perennials untouched

"[Perennials] are often overlooked," Casimirri said. Besides winter interest, the hollow stems of perennials provide shelter for beneficial insects, like native bees. And the seed heads from spent flowers of native plants, like liatris and coneflower, provide sustenance for birds. She also recommends planting native shrubs. "People are planting a lot of perennial plants, but not so much the shrubby things that give structure in the winter and perches [for birds]." Two of her favourites include common elderberry (Sambucus canadensis) and snowberry. "I see the robins on that in February, when there's nothing else out there," she said, referring to the berries of the latter, which remain on the plant well into the winter.

There are some plants that should be cut back in fall, especially if they've shown signs of disease. An example would be peonies, being careful to avoid damaging the crown of the plant, which is the fleshy knob where the stems join the root, as you cut back the foliage.

When it comes to annuals, which won't be making a return appearance, you could use the chop-and-drop method that is recommended in The Regenerative Garden by Stephanie Rose. Simply cut back plant material that is pest- and disease-free (and that hasn't gone to seed), allowing it to decompose in place in the garden, covered by leaf mold and compost.

What should be stored for winter?

Plant supports, garden hoses and watering cans, garden dcor and emptied terracotta or ceramic pots should all be placed in a shed or garage over the winter. If you've set up that DIY compost bin for fall leaves, this is where you can dump your used potting soil. If you have a rain barrel, Casimirri recommends draining it and turning it upside down so it doesn't crack, being sure to divert water away from the house so it doesn't affect your foundation.

Cleaning up the vegetable garden

Another garden you may want to pay some attention to is the vegetable garden. Pull any spent plants that may have been affected by disease, such as tomatoes. For the rest, Casimirri will simply cut healthy vegetable plants down to soil level, leaving the stalk underground so as not to till or turn the soil or dig everything up. By spring, it will have broken down.

And when it comes to leaving plants and leaves in place, seasoned green thumbs need to let go of the tidy fall garden aesthetic, embracing a space that's a little wilder like what you'd find in nature. After all, a less tamed look promotes a more sustainable garden.