Divide and Conquer: The Not-So-Scary Guide to Dividing Perennials

So, your perennial garden is looking a little… crowded. Maybe that once-perfect hosta has now morphed into a leafy monster threatening to swallow your walkway. Or perhaps your daylilies are multiplying like rabbits, making you wonder if they’ve been sneaking fertilizer cocktails when you weren’t looking. Either way, it’s time to talk about dividing perennials—a task that sounds scarier than it actually is. Don’t worry, you won’t need to wear gladiator armour (though knee pads and gardening gloves aren’t a bad idea). 

Let’s dig in (pun fully intended) and talk about what dividing perennials actually means, why you should bother, and—most importantly—how not to murder your plants in the process.

 

What Does “Dividing Perennials” Mean, Anyway?

In simple terms, dividing perennials is like giving your plants a haircut and a spa retreat all at once. Perennials—plants that come back year after year—tend to grow and spread. Over time, clumps get overcrowded, start competing with themselves, and before you know it, they’re blooming less and sulking more.

When you divide perennials, you literally dig them up, split the root system into smaller sections (with each section having its own roots and shoots), and then replant them. It’s like cloning your plants—except it’s free, and you don’t need a lab coat.

Why Should You Divide Perennials?

Besides the obvious perk of getting free plants (who doesn’t like free stuff?), dividing perennials has some very practical benefits:

1. Health Check: Plants that are overcrowded can start choking themselves out. Dividing them gives them breathing room.
2. Better Blooms: A clump that’s too dense often produces fewer flowers. After dividing, perennials tend to reward you with bigger, better, and more abundant blooms.
3. Garden Design Perks: Maybe you love your Black-eyed Susans so much that you want them on both sides of your walkway. Division lets you spread the love (literally).
4. Preventing Takeovers: Some perennials (looking at you, daylilies) are notorious spreaders. Divide and conquer before your entire yard turns into a mono-culture.
5. Plant Longevity: Think of it as giving your plant a reset button. Dividing keeps them vigorous and extends their lifespan.

 

Why Divide Perennials in the Fall?

You can divide perennials in spring, but fall is basically the plant world’s nap time, making it the perfect opportunity. Here’s why fall division rocks:

• Cooler Temperatures = Less Stress: Just like you don’t want to run a marathon in July, plants don’t want major surgery when it’s blazing hot. Fall’s cooler temps make recovery easier.
• Moist Soil: Fall often brings rain (and in zone 5, less chance of a sudden heatwave). Moist soil means roots can settle in nicely without you babysitting with a watering can every two hours.
• Energy Storage: By fall, perennials have finished their show-off summer bloom cycle and are focused on storing energy in their roots. Divide them now, and they’ll be ready to party next spring.
• Spring Head Start: When you divide in fall, plants spend the winter getting comfy in their new homes, so they burst out happy and vigorous when spring rolls around.

Which Perennials to Divide in the Fall (and Which to Leave Alone)

Not all perennials appreciate being yanked up in September or October. Some like it, some tolerate it, and some will sulk or outright die.

Good Candidates for Fall Division:

• Hostas – Practically beg to be divided in fall. Bonus: cooler weather means fewer mosquito bites while you’re knee-deep in hosta clumps.
• Daylilies – Spreaders extraordinaire. Divide them before they take over your neighbourhood.
• Peonies – Fall is the time to divide peonies, but be patient—once divided and replanted, they can take a year or two before they bloom again.
• Bee Balm (Monarda) – These guys are prone to overcrowding and powdery mildew. Splitting them up helps.
• Black-eyed Susans (Rudbeckia) – Reliable and easy to divide.
• Phlox – Dividing in fall helps prevent disease and keeps them vigorous.
• Coneflowers (Echinacea) – Another great candidate that thrives after division. 

Perennials That Prefer Spring Division:

• Irises (Bearded Iris especially): Late summer is actually their sweet spot, not fall.
• Baptisia (False Indigo): These guys hate being disturbed. Best left alone unless absolutely necessary.
• Oriental Poppies: Do better when divided in spring.
• Bleeding Hearts: Division in spring when shoots are just emerging is safest.
• Grasses (most ornamental grasses): They’re actively growing in summer/fall, so wait until spring when they’re waking up.

 

How to Divide Perennials (Without Crying)

Here’s your step-by-step guide to dividing perennials without turning it into a horticultural horror show:

Pick Your Day:

Choose a cool, cloudy day. Bright sun will stress plants out faster than you stress out when the Wi-Fi goes down.

Water First:

Give the plant a good soaking the day before. It makes digging easier (and your back will thank you).

Dig Carefully:

Use a sharp spade or garden fork to dig around the clump. Try to lift the whole root ball without hacking it to bits.

Split the Clump:

Here’s where the fun begins. Depending on the plant, you can:

• • Pull apart by hand (hostas are good for this).
  • Use a sharp knife or spade (daylilies are tougher customers).
  • Go medieval with two garden forks back-to-back and pry the clump apart. (Highly satisfying.)

Check for Dead Stuff:

Toss any old, woody, or diseased sections. Keep the healthiest roots and shoots.

Replant ASAP:

Don’t let divisions sit around like forgotten leftovers. Replant them at the same depth they were growing before.

Water Well:

Give them a thorough soak to help settle the soil around the roots.

Mulch:

Add a light layer of mulch to protect them from winter’s mood swings.

Best Tools for Dividing Perennials

You don’t need a gardening toolbox that rivals Batman’s utility belt, but a few good tools make life easier:

1. Sharp Spade or Shovel: Your main weapon for digging and cutting roots.
2. Garden Forks: Perfect for prying apart stubborn clumps. Bonus points if you use two at once—it feels like a gardening magic trick.
3. Hori-Hori Knife: A Japanese garden knife that can slice, dig, and make you feel like a garden ninja.
4. Pruners: For trimming back foliage so the plant can focus on root recovery.
5. Watering Can or Hose: Because your new plant babies are thirsty after surgery.

 

Pro Tips for Division Success

Cut Back the Top Growth:

Trim leaves and stems by about one-third before replanting. Less top growth means less stress on the roots.

Don’t Overdo It:

Divide perennials every 3–5 years, not every season. They’re plants, not sourdough starters.

Label Your Plants:

If you’re sharing divisions with friends, label them. Nothing’s worse than planting what you think is a peony and finding out it’s a clump of goldenrod.

Think Ahead:

Plan where you’ll put your divisions before you start. Otherwise, you’ll end up with a bunch of root balls sitting on your lawn while you panic about space.

 

The Free Plant Bonus

Here’s the best part: dividing perennials is like a two-for-one sale you didn’t have to wait in line for. You get new plants for free! Share extras with friends, swap with neighbours, or create a brand-new garden bed. It’s budget-friendly, eco-friendly, and makes you look like a gardening pro.

 

Wrapping It Up

So there you have it, dividing perennials might sound intimidating, but really, it’s just plant maintenance with a major side of free swag. Fall is the perfect time in zone 5 to roll up your sleeves, grab a spade, and give your perennials the TLC they deserve. Your plants will thank you next spring with more blooms, more vigour, and a garden that looks less like a jungle and more like the intentional masterpiece you meant it to be.

Stop procrastinating, sharpen your tools, and go divide and conquer. Your garden will love you for it (and so will your neighbours when you gift them some of your “spare” hostas).

Happy gardening!

 

From the archives

Mike, the Garden Guy from Georgina Garden Centre, shows you how to divide and replant hostas in the fall for better growth. This simple step-by-step guide is perfect for both beginner and experienced gardeners.