Every March, without fail, the same thing happens. We get one warm week — the snow is gone, the sun is out, and suddenly you're standing in the garden in a light jacket thinking okay, let's go. I get it. I feel it too.
But here's the thing: that urge to tear into the garden beds the moment the ground shows itself? It's one of the most common ways well-meaning gardeners accidentally do more harm than good.
This is my case for waiting — and a clear guide to what "waiting" actually means, because it doesn't mean doing nothing.
The real reason to hold off (it's not about the frost)
Most of the advice you'll find online focuses on frost risk. Don't plant tomatoes before the last frost, don't put out annuals too early, etc. That's all true. But for spring cleanup — cutting back perennials, clearing leaves, tidying beds — the more important reason to wait has nothing to do with your plants at all.
It's about the insects.
A lot of the beneficial insects in your garden — native bees, butterflies, beetles, beneficial wasps — spend winter tucked inside hollow plant stems, cocooned in leaf litter, or nestled just under the soil surface. When you clean up a bed on a warm March afternoon, you're not just tidying up dead material. You're potentially removing or disturbing insects that haven't finished waking up yet.
And here's the thing about bees that I can't stop thinking about: a single honeybee makes around a dozen foraging trips a day, visiting 50–100 flowers each time — which adds up to somewhere in the range of 5,000 flowers. Per bee. Per day. They are working so hard, and they need every single stem and leaf pile we can give them while they get their bearings in early spring.
I have my own completely unscientific version of the 10°C rule: I wait until I can see enough flowers in my neighbourhood that a bee would actually have somewhere to go. If I'm looking out the window and the street is still mostly grey and brown, I'm not in the garden yet. Once the forsythia is popping, the hellebores are nodding, and there's something blooming on every block — then I know the world is ready, and I start thinking about cleanup.
The more official rule of thumb: wait until overnight temperatures are consistently above 10°C. That's when overwintering insects are actually emerging on their own. Before that threshold, cleaning up too aggressively is essentially evicting everyone before they've even had their morning coffee.
In Hamilton, that window is typically late April into early May — not March, and usually not early April either, even when it feels like spring.
What you can do right now (in mid-to-late March)
Waiting doesn't mean staring out the window. There's actually a lot of useful, lower-impact work to do right now that will make the rest of your spring easier.
Cut back ornamental grasses. These are one of the few things that genuinely benefit from early spring attention. Grasses like Miscanthus, Karl Foerster, or Little Bluestem can be cut back to about 10–15 cm before the new growth starts pushing through. Do it now, before the fresh green makes it harder to see what you're working with. (If you wait too long, you risk cutting off new growth, and then you've just created a little green toupée situation that no one asked for.)
Assess and repair. Walk the garden with your eyes, not your hands. Look for winter heaving — plants pushed up out of the soil by freeze-thaw cycles — and gently press them back down. Check for broken branches, erosion, or drainage issues you want to address before the rush. Take photos. Make a list. This is actually one of the highest-value things you can do in March.
Prune woody shrubs that bloom in summer or fall — but not spring bloomers. Late winter and early spring is the right window for shrubs that flower on new wood: hydrangeas (panicle and smooth varieties), buddleia, and summer-flowering spirea. But if your shrub blooms in spring — lilac, forsythia, early spirea, weigela — keep your hands off it until after it flowers. If you prune it now, you're pruning off this year's blooms. (I know. Painful.)
Get your seeds going indoors. March is peak seed-starting time for zone 5b. Tomatoes and peppers need to be started indoors 6–8 weeks before the last frost, which in Hamilton typically falls in late April to early May. That means starting tomatoes in mid-March is just right. Peppers actually benefit from an even slightly earlier start. Cole crops — broccoli, cabbage, kale — can be started now too and will be ready to go out under cover in April.
The cleanup itself: how to do it without wrecking the ecosystem
When overnight temps finally hit that 10°C mark consistently, you're clear to start. Here's how I approach it in a way that keeps the garden healthy:
Cut gradually, not all at once. Instead of clearing an entire bed in one session, work in sections over a few weeks. This gives any late-emerging insects a chance to get out before you move through.
Hollow stems: cut and leave. When you cut back pithy-stemmed perennials — things like Joe Pye weed, rudbeckia, echinacea — cut them, but leave the cut pieces in a loose pile at the edge of the bed for another few weeks before bagging or composting. Native bees nest in those stems and some may still be emerging.
Leaf litter: don't rush it out. This is the hardest sell for tidy gardeners, and I understand why. But leaves in the beds are functioning as mulch, insulation, and habitat all at once. If you have a thick mat that's smothering emerging perennials, carefully peel it back — but don't strip the beds bare. Tuck some of it to the side of the bed and leave it to break down on its own.
Don't add fresh mulch yet. Wait until the soil has actually warmed before putting fresh mulch down. Adding it too early holds the cold in and can delay the warming that plants and soil organisms are waiting for. When you do mulch — and I'd encourage you to — go with untreated cedar at about 8–10 cm deep. That's the depth where you get real benefit without smothering roots or creating problems.
The short version, if you want it
March: start seeds indoors, cut back ornamental grasses, prune summer-blooming woody shrubs, assess the garden without touching much else.
April (once nights are reliably above 10°C): begin gradual cleanup, working in sections. Cut and temporarily stage hollow stems. Peel back leaf litter carefully, don't strip. Add mulch once the soil has warmed.
Late April / Victoria Day weekend: now you're really cooking. Transplant seedlings, divide perennials, plant cool-season crops directly. Most spring bloomers will be done flowering by now and can be pruned if needed.
The itch to clean is real, and I'm not here to tell you to ignore it completely. But the garden will genuinely do better — and so will the insects and birds that depend on it — if you let March be a planning and light-prep month instead of a full reset. The mess is doing more work than it looks like it's doing.
It'll be there. Take your time.
Want help figuring out what's worth tackling first in your specific garden this spring? That's exactly what a growing consultation is for.