How To Prepare Perennials For Winter In Zone 3-4 Canada
Another harsh Winter is right around the corner here in Zone 3-4 Canada (yikes!). And your perennial plants need a little love and support to help them survive it. This complete guide will not only help your perennials survive Winter but allow them to thrive come Spring. We’ve got your covered with these practical tips for preparing perennials for Winter in Zone 3-4 Canada.
This blog post covers:
Understanding Gardening Zones 3-4 in Canada
How Late Can You Plant Perennials In Zone 3-4 Canada
Should I Water My Perennials Before Winter
Should I Fertilize My Perennials Before Winter
Will Perennials Survive Winter in Raised Beds in Canada
How to Overwinter Perennials in Raised Beds
What Should I Do With My Potted Perennials In The Winter
When To Start Preparing Your Perennials For Winter
What Perennials Should I Cut Back In The Fall
5 Easy Steps For Preparing Perennials For Winter In Zone 3-4 Canada
Understanding Gardening Zones 3-4 in Canada
First, it’s key you understand what gardening zone you are located in.
Why?
It will help you prepare for your first Fall frost date!
This is so key for perennials as that first frost means the end of their season. And ultimately the start of preparing your perennials for Winter.
So where Is Zone 3-4 In Canada
Well there are actually gardening zones 3-4 located across the entire country.
Here’s a breakdown of grow zones in a few major Canadian cities:
- Mackenzie, BC — Zone 4a
- Edmonton, AB — Zone 4
- Calgary, AB — Zone 4a
- Saskatoon, SK — Zone 3b
- Regina, SK — Zone 3b
- Winnipeg, MB — Zone 3b
- Thunder Bay, ON — Zone 4b
- Mont-Tremblant, QC — Zone 4b
- Edmundston, NB — Zone 3b
- Millertown, NL – Zone 3b
How To Calculate Your First Fall Frost Date
There’s a helpful and free online tool you can use to calculate when your first frost date will be, which I will link here next!
Generally, the most effective way to understand when your first frost date will be for your garden is to;
- Pay attention to your local weather forecast
- Take notes year over year
- Record data on the microclimate in your own backyard
Now, here’s a great tool I like to use to find average first frost dates across Canada & the U.S.
The Farmer’s Almanac Frost Date Finder – it’s so easy to use and free! Just enter your postal/zip code and it will populate
My blog Your First Fall Frost Guide: The When, What, Why & How covers all this and more. I invite you to give it a read if this information is new to you.
How Late Can You Plant Perennials In Zone 3-4 Canada
Surprisingly, you can plant perennials in Zone 3-4 Canada quite late into the Fall.
While there are some contradicting opinions on the matter, my personal experience is that you can plant perennials as long into the Fall as the ground is not frozen. The same goes for trees and shrubs.
Further to this, some gardening experts even say planting perennials later into Fall is better. Why?
Because there is less stress on perennials in the Fall. Temperatures aren’t as hot and the plants aren’t focused on putting on new growth.
Instead, Fall planting allows perennials to easily set roots and settle into their new home.
So should you plant perennials in the Fall? The answer is a resounding yes!
The same goes for trees and shrubs. Both do even better when planted in the Fall!
Check out my post Why Fall is the Best Time to Plant Trees in Canada for more info on this topic!
We plant our trees in the Fall every year and have always had success. I stand confident you will too!
Should I Water My Perennials Before Winter
The answer is an absolute yes! Please do water your perennials regularly, deeply and thoroughly before Winter.
Here’s why.
Moisture in the soil acts as insulation for your roots. It will help them transfer sugars from the leaves down to the roots ahead of Winter.
Well watered perennials are also more likely to survive excessive winds, which are pretty common during Canadian Winters!
Now what happens if you don’t water your perennials before Winter? Well, your plants will likely have brown foliage come Spring and might not bounce back.
So yes, well-hydrated plants are much better equipped to survive Canadian Winters in Zone 3-4.
We’ve found watering our perennials with drip lines throughout the entire season and into Fall works really well.
We have our drip lines on an Orbit timer so it makes it completely hands off. We run our drip lines from June until October for 30 minutes each morning around 6:00am.
Here’s the drip lines we use and love! They’re a heavy duty tubing that is porous and slowly soaks water along the base of each plant. I definitely recommend.
How Long Should I Water My Perennials For In The Fall
You can continue watering your perennial plants up until the ground freezes.
The exact timeframe will depend on your grow zone and when you get your first hard Fall frost. So there’s no exact date that is universal for all gardeners.
However, I like to use this rule of thumb!
I wait until our first fall frost has “killed” our perennials for the season (usually the first week of October here in my Zone 3 garden).
Then I water the plants a few more times. This gives me a little added insurance that they are well hydrated for Winter. After that, I turn off the water and begin my Winter perennial prep — more on that next!
Should I Fertilize My Perennials Before Winter
It’s best not to fertilize your perennials before Winter.
The risk is that your perennials will want to continue putting on new growth in the Fall. However Fall is when perennials should instead be hardening themselves off for Winter.
Any new growth a perennial puts on in the Fall will likely be killed off anyway and not rebound the following Spring. Furthermore it will confuse your perennials about what stage of the season they’re heading into. This could lead to more issues the following season.
Instead, prioritize fertilizing in the Spring and Summer when plants should be putting on new growth. Of course, I encourage you to choose an organic fertilizer!
You can find all my fertilizing tips here in this blog 3 Easy Ways To Organically Fertilize Your Veggie Garden In The Summer.
When Should I Stop Fertilizing My Perennials In Zone 3-4
It’s safe to say you can stop fertilizing your perennials by mid to end of July in Zone 3-4.
This is especially true if you’re applying a slow-release fertilizer. These fertilizers release small amounts of nutrients over a prolonged period of time. So you want to ensure your plant uses up any fertilizer before cold weather comes.
The same goes for compost. Avoid top-dressing perennial plants moving into Fall. Compost is also slowl release.
On the contrary, applying a kelp-based fertilizer on the foliage and leaves of your perennials in the Fall is actually beneficial!
Kelp can help perennial plants manage stress that comes with the first frosts of the season.
My absolute favourite kelp-based fertilizer is Sea Magic. It’s water soluble and great for not only perennials but edibles, annuals, flowers and houseplants too!
I simply add my diluted Sea Magic solution to a spray bottle and mist my perennials all over. I don’t do this every single year. But the years I do I find my perennials perk up faster in the Spring.
Will Perennials Survive Winter in Raised Beds in Canada
The answer to this question is a little complicated. But for the most part, yes perennials will survive Winter in Zone 3-4 in raised beds.
Here’s a few factors that could lead to your perennials not surviving Winter in a raised bed:
- The raised bed is very high off the ground, meaning it has little insulation
- The perennials in the raised bed were not well mulched before Winter
- The type of perennial was not well suited to a raised bed
In other words, most perennials in most styles of raised beds will survive Winter. But of course, there’s always a few exceptions. Plus a few key things you must do in order to overwinter them properly. That’s next!
How to Overwinter Perennials in Raised Beds
Now, here’s my personal list I follow of simple yet effective tasks for overwintering perennials in a raised bed.
First, start by cleaning up your perennials. Note that I didn’t say cut back your perennials. Because not all perennials should be treated equal.
I cover what perennials you should cut back in the Fall a bit further down in this post. However my simple rule of thumb for cutting back perennials is as follows;
Leave perennials standing unless diseased and/or damaged. Instead, do your perennial pruning in the Spring.
I’ve found this method is effective because the dead foliage actually catches leaves, debris and snow, insulating plant roots’ further.
It’s a less is more approach and guess what — it works!
The next step is to mulch.
Mulching is so key! And something I’ve cover in great detail in these posts;
While I love using garden straw to mulch most of my plants, leaves are also effective…and free!
You can pile dry leaves about 6″ over perennial beds. They do a great job at insulating plants throughout Winter!
These leaves can then be chopped-up next season using the lawn mower, becoming beneficial leaf litter. Or simply toss the leaves in your compost pile. They are excellent organic matter to add in.
What Should I Do With My Potted Perennials In The Winter
Now this is a question I get often! And it’s a tricky one to answer…
Because you could successfully overwinter perennials in containers in Zone 3-4 Canada. However, you would need to do a few things perfectly, such as:
- Move your container perennials to an area of your yard that is protected from Wind and excessive snowfall
- Ensure your containers are well watered and don’t have too many drainage holes
- Insulate your containers (top, sides and bottom) so the roots don’t get damaged
The main reason why perennials in containers die overwinter is because the roots are not well insulated enough.
This can be tricky to do when your plant is in a plastic pot. But it’s not to say it’s impossible.
I seen gardeners who will go as far as to wrap their containers in several layers of poly or plastic.
So let’s answer the question — what should I do with my potted perennials in the Winter?
Here’s what I would suggest.
- Bring your potted perennials into a garage, shed or unheated greenhouse over Winter and allow them to go into dormancy.
- Choose an area that will still drop to freezing but not as cold as being outdoors.
- Be sure they have access to sunlight.
- Do no water them.
- Bring them outdoors in early Spring to “reawaken.”
When To Start Preparing Your Perennials For Winter
You can technically start preparing your perennials for Winter as soon as nighttime temperatures begin dipping. This could be anything from 10°C/50°F and cooler.
As I mentioned earlier, the first step in preparing your perennials for Winter should be watering them consistently.
From there, the rest of your prep can begin after you’ve had your first Fall frost. At this point, the foliage on your perennials will have likely died. And plants will have stopped growing.
So what exactly should you do to prepare your perennials for Winter? Well I’ve broken it down into five easy steps for you!
5 Easy Steps For Preparing Perennials For Winter In Zone 3-4 Canada
Follow these five easy steps to successfully prepare your perennials plants for a Canadian Winter.
These are the tips I apply to my Zone 3 garden where Winter temperatures often hit -40°C! Wow I hate to say that, but it’s true!
And my perennials always survive. So safe to say, I’m pretty confident in these 5 tips.
Step 1: Water, water, water!
We’ve covered this in great detail already! But if you for some reason skipped over all that, let me say it again.
You should 100% water your perennials regularly, deeply and thoroughly before Winter. This means water daily and ensure the soil is saturated down to the roots.
Moisture in the soil acts as insulation for your roots. It will help them transfer sugars from the leaves down to the roots ahead of winter.
Your perennials will have a much higher chance at thriving come Spring if well watered in the Fall. Simple as that!
Step 2: Gently prune and clean-up
Not all perennials are created equal. And so, not all perennials need to be pruned.
I’ve included a list below for you covering what perennials you should cut back in the Fall in Zone 3-4.
But to be safe, choose to gently clean-up and cut back your perennials rather than doing a heavy prune.
Clean up dropped leaves from any disease or pest prone plants such as lilies, milkweed, peonies and rudbeckias. This will help limit disease and pest pressure for the following season.
Use a clean pair of garden sheers when pruning perennials, I love these ones!
Step 3: Weed now for an easier Spring
Trust me, it’s so much easier to get rid of weeds in the Fall than the Spring.
For one the weeds are already dead thanks to the frost. Secondly, the ground is easy to work!
Plus, weeding in the Fall will reduce the number of weeds that pop-up next Spring. You’ll be reducing the number of weed seeds that self-seed. So it’s a win-win!
Step 4: Lots of mulch
Whether you go with straw or leaves or another organic matter. Your perennials will thank you for mulching!
Feel free to apply mulch over your perennials with a heavy-hand. You can apply up to 6″ of mulch.
Pro Tip: When using straw mulch, water it down to ensure it binds together and does not blow away in the wind.
There really isn’t any harm to applying too much mulch over Winter. The only thing to consider is that you’ll want to ensure you remove all mulch come Spring. Otherwise your plants will have trouble putting on new growth.
Step 5: Burlap as needed
While perennial flowers do not need burlap, trees and shrubs benefit from it greatly. Newly planted fruiting trees and evergreens will especially benefit!
Burlap protects plants from damaging winter winds and buffers against damage from winter sun or warm spells.
Here’s two things to consider when applying burlap:
- Use poles or wooden posts to create a frame about 6″ away from the branches
- Always avoid wrapping the burlap directly on the tree or shrub. It can do more damage than good.
And there you have it!
Those are my five easy steps to successfully prepare your perennials plants for a Canadian Winter. I hope they help!
I would love to hear any other tips you have! Leave a comment below. I answer all comments and love hearing from you.
What Perennials Should I Cut Back In The Fall In Zone 3-4
First, it’s important to note that these tips are specific for Zone 3-4 where Winters are particularly harsh.
Again, not all perennials need to be cut back in the Fall. In fact, many can get damaged from a Fall pruning.
Some gardeners may tell you they prune their perennials each Fall religiously. And this is ok too! What I’m suggesting is that waiting until the Spring is just the safer bet.
With that being said, I encourage you to also do some additional research on each specific perennial before getting started.
Now here’s a quick and dirty list of what perennials benefit from being cut back in the Fall:
- Peonies — trim the stems down to the ground after your first frost
- Daylilies — cut the foliage down to about 2 inches above the ground after your first frost
- Hostas — cut close to the ground after your first frost
- Bearded Iris — cut the leaves back to about 4-6 inches above the rhizomes
- Bee Balm — trim the plant to ground level to avoid powdery mildew the following season, but waiting until Spring is also fine
- Phlox — cut to ground level once plants begin to die back
- Columbine — trim it down to about 3-4 inches above the ground after the first frost
- Sedum — cut them back to just above the crown after first frost
- Yarrow — cut stems back to ground level, but leaving until Spring is fine too and will promote self-seeding
- Coreopsis — cut the stems to about 2-3 inches above the soil after first frost
- Gaillardia — cut back to about 6 inches above the ground after first frost
- Heliopsis — trim to the ground after first frost, but not necessary to do any pruning at all
And there you officially have it!
This is your extensive guide covering how to overwinter perennials in Zone 3-4. If you’ve made it all the way to the end, congratulations!
That was a lot to cover and I’m glad we did it together.
Winterizing perennials will help you have a thriving garden come Spring. So please do take the time to care for your plants.
I hope this post covered everything you need to know about how to prepare perennials for winter. And if I’ve missed something, I’d love to hear from you. Comment below!
You can also follow me on Tik Tok and Pinterest for more organic gardening content.
Happy Fall gardening, friends!
have definitely learned to love burlap the hard way. is more or less mandatory for many of our young trees including lilac, cedar and pear which the deer love and will decimate. they even ripped the tree guards off the pear trees this fall…