Mint is a wonderful culinary herb and a beautiful leafy green plant that’s very attractive in the home garden. It’s also a prolific spreader. To keep mint under control, it’s best to grow it in a pot. Learn how to transplant mint, whether from the nursery pot, last year’s pot (which it’s outgrown), or even dug up from the ground. Also learn about its extraordinary root system.
One of the rites of passage for beginning herb gardeners is to make the mistake of planting a crazy, propagating plant that quickly grows out of control and takes over the garden. Lol.
My mistake was lemon balm, a distant relative of (but in the same family as) today’s subject. Lemon balm spreads aggressively through both its root system and its surprisingly hardy and portable seeds. Such a mess, I cannot tell you. It took over everything, smothering even purslane and dandelions in its path. I still find lemon balm sprouts in odd places in the yard to this very day.
But I’m here now so you can learn from me: don’t set yourself up for future headaches by planting something invasive like mint in the ground. There are completely sensible and legitimate reasons for letting mint run wild – if you’re an herbalist, for example, and need large quantities for your business – but for most backyard gardens, you’ll want to keep it on a tight leash and keep it in – or transplant it to – a container.
Mint is a perennial herb in the Lamiaceae family, of which there are well over 7,000 varieties, from small house plants to large shrubs. Most of what you’ll find for purchase at the local garden center are aromatic mints with lovely and interesting flavors that are prized in the kitchen: the common spearmint and peppermint, of course, but also lemon, ginger, chocolate, pineapple, orange, licorice, grapefruit, lavender, and more.
I’m currently growing peppermint, spearmint, orange, and ginger mint in my container garden as perennials – see photo above for three of them.
All of these amazing plants share one thing in common: they grow fast, and they spread far and wide via their elaborate and aggressive root systems.
Hey fellow garden enthusiasts! I’ve been growing and dividing mint plants for years, and lemme tell you – it’s one of the easiest plants to propagate Today, I’m gonna share my tried-and-tested method for dividing mint plants, plus some cool tips I’ve learned along the way.
Why Should You Divide Your Mint Plants?
Before we dive in, here’s why you definitely wanna divide your mint:
- Prevents overcrowding in pots
- Creates free new plants (who doesn’t love free stuff?)
- Keeps your mint healthy and vigorous
- Perfect way to share with friends and family
- Controls mint’s crazy-aggressive growth
Best Time to Divide Mint
The perfect timing is when your mint plants are waking up from their winter snooze and starting to show new growth. Usually, this happens in early spring. But honestly mint is pretty forgiving – I’ve divided mine successfully at other times too!
What You’ll Need
- Sharp, clean secateurs or scissors
- Fresh potting compost
- Containers with drainage holes
- Some grit for drainage
- Your overgrown mint plant
- Optional: thin layer of fine grit for top dressing
Step-by-Step Guide to Dividing Mint
1. Prepare Your Plant
First things first, take your mint plant outta its pot Don’t be shocked if you see the center has died back – that’s totally normal! Mint grows outwards using runners (technically called stolons), and sometimes the middle just gives up
2. Check the Root System
Gently remove excess soil and look for:
- Healthy white roots
- Horizontal stems (runners/stolons)
- Natural division points
3. Division Time!
Here’s where the magic happens:
- Look for natural separation points
- Identify sections with both roots and stems
- Using your clean secateurs, snip the plant into sections
- Each section should have:
- Some healthy roots
- At least couple of growth nodes
- Some vertical stems if possible
4. Potting Up Your Divisions
Now for the fun part:
- Fill your pots with gritty compost
- Plant each division at the same depth it was growing before
- Add a thin layer of grit on top (this helps keep moisture in and weeds out!)
- Water well but don’t drown ’em
Pro Tips from My Experience
- One plant can easily give you 5-8 new plants – seriously!
- Even sections without roots can grow if they have healthy nodes
- Use gritty compost – mint loves good drainage
- Keep your new plants in semi-shade while they establish
- Don’t forget to water regularly but not excessively
Common Problems & Solutions
Sometimes things don’t go exactly as planned. Here’s what to watch for:
-
Rotting Centers
- Normal for older plants
- Focus on healthy outer growth
- Remove any mushy bits
-
Poor Growth
- Check drainage
- Ensure enough light
- Don’t overwater
-
Failed Divisions
- Make sure cuts are clean
- Keep soil slightly moist
- Protect from direct sun initially
Aftercare for Your New Plants
Your baby mint plants need some TLC:
- Keep them in a semi-shady spot
- Water regularly but don’t overdo it
- Pot up when roots start showing through drainage holes
- Pinch out growing tips to encourage bushiness
Making the Most of Your Mint
Now you’ve got multiple mint plants, here’s what to do with ’em:
- Fresh mint tea (my absolute fave!)
- Give as gifts to gardening friends
- Create a mint variety collection
- Use in cooking and cocktails
- Dry some for winter use
Final Thoughts
Dividing mint plants isn’t rocket science – it’s actually pretty fun and rewarding! I usually do mine once a year, and it’s amazing how many new plants you can get from just one pot. Remember, mint’s pretty much indestructible, so don’t stress too much about getting it perfect.
FAQs
Q: Can I divide mint in summer?
A: Yeah, you can, but spring’s better when plants are naturally in growth mode.
Q: How often should I divide my mint?
A: Once a year is plenty, usually in spring when new growth appears.
Q: My mint looks dead in the center – is this normal?
A: Totally normal! The plant focuses energy on outer growth through runners.
Q: Can I plant divided mint straight in the garden?
A: Better keep it in pots unless you want it taking over your whole garden!
Now you’re all set to become a mint-dividing pro! Got any questions? Drop ’em in the comments below. Happy gardening, folks!
A Look At Mint’s Incredible Root System
The root systems of mint have two primary features:
- fine, fibrous tendrils that drop vertically from the plant to intake nutrition from the soil, as well as anchor the mint plant in place; and,
- rhizomes, which are a type of plant stem that grows underground and can extend horizontally for great distances, producing offshoots that break the soil surface to create a new plant.
The roots themselves are nothing to shout about, as they produce the typical root ball that we’re all familiar with. But the rhizomes are something else entirely.
They’re clearly identifiable as thick stems (when not dusty with dirt, that is – see a nice shot of them in the photo below) and grow aggressively outward from the plant in a web, with the sole intent of creating new mint plants. And they’re very, very good at it.
The photo above is a one-year-old peppermint plant. When I bought this plant last year, I left it in the nursery pot and set it in some soil on a raised garden bench for the summer. Those rhizomes are just one year’s growth, winding around the interior of the pot. Imagine if those rhizomes had been free to roam the yard!
I hope the photo above drives home the advantage of growing mint in a pot. Even if you’re an avid cook or a connoisseur of mint tea or mojitos, it would be quite the feat to use up all of the plant’s leaves in one season. The average home gardener does not need an ever-more-sprawling plot of mint.
If you’ve just bought your first mint plant from the garden center, check out my guide for how to grow mint, complete with pro tips and advice.
When to transplant mint
It’s fairly easily to know when a mint plant needs to move to larger pot. In most growing zones in the U.S., mint will die back in the winter (store the pot in an unheated garage or shed, or at least protected from wind outside). It will, in fact, look quite distressingly dead. But, hold steady.
In the spring, when the temperatures regularly warm above 55ºF, watch for mint’s revival. You’ll begin to see tiny leaves and shoots emerge from among the dead stems.
Leave the plant to do its thing for a bit. If the weather is dry, give it a light watering now and then.
Once the growth begins in earnest, you’ll see a pattern emerge. If the green growth is consistent across the surface of the soil, the plant doesn’t really need repotting.
But if the center of the pot has no new growth, with new green sprouts ringing the edges, it definitely needs to be moved to a larger pot. The rhizomes beneath the surface drive the new season’s new growth, and if the sprouts appear only around the edges of the pot, that means the rhizomes have grown outward from the center of the plant – as is their imperative to do, to spread outward – and are running around the walls of the pot (remember the photo above) because they have no room to do anything else.
Mint’s root ball is not particularly large nor deep, so you don’t need to step up to a significantly larger container to transplant mint. I usually just go one size up (which, in the U.S., pots sizes usually come in 2″ increments), acknowledging that the plant might need repotting again next year. Make sure the pot has a drainage hole.
Choose a pot that’s large enough for the plant to sit in comfortably, with room below for a fresh soil base of an inch or so, and enough space around the sides to fill in with new soil.
If the root ball is particularly compacted, you can gently break up the roots a bit by splitting the ball in half from the bottom up. I normally don’t, though. I also leave the rhizomes alone, even when they look quite squooshed.
If the pot’s drainage hole is more than a 1/2″ in diameter, place a small rock, a square of screen, or even a coffee filter, over the hole, to prevent soil from crumbling out.
Add a layer of soil to the bottom of the pot, and then set the plant in the middle. Add soil around the sides evenly so that the plant remains centered. Continue adding soil up to the level of the original surface. Press the edges down to firm the soil, and water well.