How invasive is mint?

S Smithsson wrote:When ours grew into the lawn, we just mowed it. BEST mowing experience ever!!

Sandy

I had the same experience with oregano....loved mowing that area of lawn!

You can plant it in a pot in the ground, ignored it will still successfully escape, but its much easier to deal with an annual cut back.

I'm experimenting using mints as ground cover with some perennial crops. I've opted for mints because they are easy to pull out the excess and I can process some of the excess for home use, trading, gifting, and selling. Plus they can take being trampled upon as I walk among the crop plants. Best yet, they smell great.

Chocolate mint: I started this experiment last spring by planting it around the base of a couple macadamia nut trees. I normally keep a grass clipping mulch around the trees, but want to plant something so that the roots will prevent erosion, help improve the soil, and deter some pests. Don't know yet if I can achieve all those goals. But the mint took ok and started spreading to fill in the gaps. During harvest season I used a mower to shorten the height so that I could see the nuts to pick up. Wow, that smelled super! Now that it's not harvest time, I'll letting the mint grow to normal height.

Peppermint: I've planted some among the pumpkin vines. Normally I grow pumpkins among grass because the grass helps confuse the pests. But this fall I create a pumpkin growing area with no grasses. Planted peppermint instead. I'm hoping it will keep the weeds down and hide the pumpkin vines. At the very least, it will smell great when I search for pumpkins to pick.

Spearmint: I think this mint is taller and more aggressive than either of the first two. So I've planted it among the pineapple plants, which should be able to compete with this taller mint. From past experience I know that I could easily pull out the taller stems, or cut them off with a hand sickle, thus selectively removing any growth that threatens to cover a young pineapple plant.

All three areas are not near my annual veggie plantings. I think I should be able to readily control the invasiveness, while at the same time taking advantage of their invasive nature. We shall see.

Something else to note: I've learned that mint will cross-pollinate if given the opportunity to flower & seed; so I now keep my stock plants for the nursery in different areas and trim the blooms to minimize the risk.

It's not invasive in my S. FL garden. I can't keep it alive for long, except for the woody-stemmed shrub that is some form of mint. It's lasting for years, but I've had no ground-layering so I hope it's long-lived!

I had a garden bed that started out as grass several years ago, I mulched it and planted annuals and perennials, including some larger shrubs.   For a while when everything was small I thought the mint was invasive,  now it is in shade and I can hardly find enough to make a cup of tea.  
a similar story on the power of shade:
I remember walking one day in New Zealand through some kind of regenerating forest, probably an old pasture left alone.   The pines, and probably some native trees had shaded the gorse.  There were a few scraggly gorse shrubs hanging onto life, but mostly just grey gorse skeletons with a big diversity of other plants taking hold.  A long process for sure but often if succession is allowed to play out so called invasives are only super successful at a certain stage and fade away when conditions change.

It never, ever, ever, ever stops. Pot it, or be plucking it for the rest of your life!! Lol

William Bronson wrote:
I think it is easy to pull,  but it comes back easily.

Yes, like invasive grasses, pulling it often leaves a broken-off bit behind, and that's enough to grow a new plant.

My brother planted a 6 inch clump of spearmint in his yard in north central Kansas.
25 years later it had stopped at the sidewalk and the driveway.
It had spread about 10 feet in the other 2 directions.
It was doing much better on the sunny side of the privacy fence than the shaded side.
He had soooooo much mint that any family member, friend, neighbor,  whoever could pick all they wanted and not affect it.

Mint will absolutely take over any wet areas. It's rare to find a pond, creek, wetland, etc around here that doesn't have peppermint or its parent species. Peppermint, incidentally, is a sterile hybrid, and will not spread through seeds. It still manages to be a problem just by sending out runners...

It definitely needs water! I bought a mint plant, and managed to kill it.  The peony planted  18" away lived, but the mint?  kaput.

Sandy

Nicole posted a couple of stories about mint so I’ll follow her lead and give you one here. In the early 20th century, my great-great enterprising relatives, so my mother tells me, farmed in Oregon in places that were logged and left without trees but enough rain to produce a bumper crop of mint. The family would mow, scythe, and gather vast quantities of the plants then stuff it into a horse-drawn-wagon that held a fairly large still. Camping in the field, they would steam (maybe not the right term) the mint and produce a barrel (not sure how big) of pure mint distillate. They’d leave the large quantity of spent plant matter and the residual water from this process in the field. They guarded the mobile distillery with guns during the process. The final harvest of pure mint distillate (oil) was worth over $50,000 at that time (probably the wholesale value, not their earnings - or maybe it was). Apparently, the product was used in everything from toothpaste to gum and candies. Maybe those old-timers knew to think twice before eradicating anything.

P.S. A corroborating source found on https://en.wikipedia.org/wiki/Peppermint_extract, see reference #2:
"Peppermint oil: Synopsis of information". United States Bureau of Foreign and Domestic Commerce. 1949. Retrieved 13 August 2021.

I have had both experiences with mint.  At first I couldn't keep it alive.  I thought invasive, people don't know what they're talking about.  I finally got one peppermint, and one spearmint to live.  The first year it spread a little, but it was easy enough to keep in check.  Year two was a different matter. The raised bed the peppermint was in was a solid mass of mint roots. It had managed to get out of the bed and spread through the walkways.  I had to totally redo that bed. I left the mint in the walkways.
This year I redid my garden paths. I removed all the weeds, put down new weed cloth, and wood chips.  I'm actually sad to say no mint has popped through the edges.
Now I plant mint in large plastic pot. I cut the bottom out, and make sure to place it so the top of the pot is a couple of inches above soil level.  For me this does the trick. I get beautiful mint, that stays where it's put.
I agree and disagree about the water.  For me anyway I must keep it watered the get it established.  Once it's established it can handle just about anything.  It didn't seem to mind over watering when I forgot the water on.  I didn't water my walkways so that mint only got the water that seeped from the raised beds. There was a time or two I thought it was dead, but as soon as a little water would hit the mint would pop up.  So the above ground mint would suffer in drought, but the roots seemed to make it just fine.
I don't think mint is evil, I would trade it for Bermuda grass any day of the week!  At least mint is useful, and smells good.

Of course it depends on so many factors: the soil, the (micro-)climate, how you use it, etc.

What I found out about the mint in my garden is: it doesn't 'overgrow' or 'spread out', it only 'moves'. One year it grows here, the next year it grows there and the next-next year it grows in another spot ... It doesn't stay at the same place all the time.
Carefully watching the mint plants I can see how this happens. They have long stems that do not grow upright. Only the top part grows upright, but the lower part lies on the ground, and it makes little roots ... Using those stems with roots it moves itself through my garden. This is the 'ordinary' mint (maybe spearmint).
I have other mint species with other habits too. One of them is water-mint, a plant that loves having its roots in very wet soil. So that one never moves far from its small pond. And another mint, with somewhat 'hairy' or 'wooly' leaves  doesn't grow and move as fast.

The circumstances of my garden: I live in Drenthe, a province in the Eastern part of the Netherlands, with very sandy (and a little acid) soil. Winters aren't very cold, summers aren't very hot, often it's cloudy and it rains. My front yard has a lot of sunlight (if the sun is shining ...), during all morning and half the afternoon. That's where the mint grows (for over 5 years).

Kc Simmons wrote:Something else to note: I've learned that mint will cross-pollinate if given the opportunity to flower & seed; so I now keep my stock plants for the nursery in different areas and trim the blooms to minimize the risk.

Yes, I was taught that Peppermint (Mentha xpiperita) is a crossed species. And there are some others too. Many of those crosses are sterile (don't produce seeds).

I'm speaking about peppermint and mojito mint in zone 4b and sandy soil: In one word, yes, it can be very invasive. Unlike quackgrass, however, the roots run along the *surface* of the soil, so limiting their reach is relatively easy:
1/ Never allow it to seed. That is the most important! Mint seeds that are properly stored should remain viable for 2-4 years. In the wild, however they will sprout and propagate as soon as the conditions are right.
2/ plant them in beds, sinking the edges about 4".
3/ it will "trail over the edge of the bed", so be ready to stop it by plucking mercilessly anything that roots past the bed's edge.
Even though quackgrass has deeper roots, mint competes successfully with it, so that should give you an idea: I'm allowing mine in 2 beds and also on the edge of the garden. It loses a little ground when I harvest the mint but quickly regains it within a week, especially if I mow the edge of the garden. [Actually, that seems to spur the mint to root even farther, as the bits of mint stems, if they find a little bare soil and one good rain event will roots right there!
If you want to propagate mint, , you can buy a sprig, remove the bottom leaves that you can use for tea, Take a pencil and make a little hole. Plant the stem and the top leaves and give it a little drink. It will work in any season that you can plant a pencil in the ground.

There was one thing about mint (growing here) I forgot to mention: there are small shiny dark blue beetles (Chrysolina coerulans) which eat the mint leaves. At my allotment garden they do much damage to the mint! But I read they're common in South - middle Europe (since a few years also here in the Netherlands). Probably they are not (yet) in America.

I've heard that for years and every time mint is mentioned how invasive it is. I'm by far not the greenest thumb of all, but I can grow stuff.

My mint has never been out of control. The best patch I had was next to the house and semi contained with cinder blocks for a kinda raised flower bed. It got tall, I harvested it for later use. I miss that patch of mint. That was back in Nebraska.

The story now here in NorCal, is quite different. I have 3 potted mint types, technically 4 now I remember I have an odd ginger mint that doesn't seem happy enough to want to escape it's 4inch pot.

Anyway, I gifted my partner's mother a chocolate mint (my favorite cultivar) and she stuck it in the ground some... maybe 5-6yrs ago? I think this is the first year it's been not so depressed. It's not very tall and struggling to flower. Needless to say the pollinators aren't getting much benefit from it either.

I won't get to harvest from that patch. Its' spread very little and where it has it'll make a nice pot to sell at the farmer's market. I had constructed a very small rectangular box to keep it "contained." More like a marker to where that mint is since it was planted at the head of a garden bed. This mint does not like the rock and clay and hellish hot temperatures.

It depends on the climate. On the West Coast where you get 3 to 7 months of little or no rain every summer, it doesn't tend to be invasive. Most species of mint are aquatic herbs and although some can survive drought for a while, there aren't many places where they will get both the light and moisture they need to really thrive and spread. I've seen lemon balm take over a seasonally dry creek bed once, I've seen one spearmint plant growing wild by a river. At a construction job site where the soil was moist year round from the mountain above, I found some peppermint growing wild, but even then, it was only thriving because a bulldozer had come through and plowed all the native wildlife into the ground. This was in a city and it had probably come from someone's yard nearby.

Hmmm... So you live in a rock, clay and hellish temps valley in Northern California? It must be a booger to grow anything there. If mint won't grow, I wonder what else you can grow in your garden... I would think that a "valley" might collect silt in the long run, but that benefit hasn't come to you yet. Hmmm...
This source from Miracle Grow: "Mint will grow either in full sun or part shade, though it definitely benefits from afternoon shade in the hottest regions. It also adapts readily to a variety of soils, but the ideal is moist, well-drained, and rich with organic matter".
I don't use Miracle Grow myself, but these commercial enterprises that sell various forms of fertilizers/ amendments, as a source have one benefit to us: They do a lot of comparing in trial runs, so when they tell you "afternoon shade in the hottest regions", it tells me that your mint might be OK on the north side of the house, in your "foundation plantings", which you might have an easier time irrigating. [That's for "moist".] For "well drained", in your  rock and clay soil, that means "amendments" and "beds". I don't know if you have to fight with termites, but if you can, you might want to pile chips along your foundations and make a border. Incidentally, I always sink my borders 3-4" minimum so the lawn doesn't come in: Grass *loves* chips, well drained, moist environment.
You definitely have several challenges there, and I feel for you. As much as I hate bringing in material from outside sources, that might be your best solution. Think long term soil building. The chips will also cool the soil, especially if you can irrigate a little. Do you collect rain water? How much rain do you get a year where you are and what is the surface of your roof? NOAH says between 11.5" in Fresno to 27.7" in Napa, so definitely less than us in Central WI [34"].
https://www.currentresults.com/Weather/California/average-yearly-city-precipitation.php
You definitely need to make every inch of precipitation count, maybe also take advantage of grey water if you can.
Again, think long term, start small, increase footprint of garden/orchard a little each year. Good luck to you.

Never any guarantees. Plant in containers if worried. I have 6 or seven types of mint. I keep them in different areas. Planting varieties too close can change them and they can cross. Changes their flavor. They will spread, and escape their beds. I don't mind. My lawn has chocolate mint in some areas, and beautiful patch of great pineapple mint near the septic. I like it wild and variable.. I love to mow. The smell is heavenly.. The only mint I cannot seem to grow is spearmint. Planted in 5 different locations....it dies on me in sun or part shade. I have plenty of rain in south Mississippi. I keep trying. I love a challenge.😊

Paula Hunt wrote:Never any guarantees. Plant in containers if worried. I have 6 or seven types of mint. I keep them in different areas. Planting varieties too close can change them and they can cross. Changes their flavor. They will spread, and escape their beds. I don't mind. My lawn has chocolate mint in some areas, and beautiful patch of great pineapple mint near the septic. I like it wild and variable.. I love to mow. The smell is heavenly.. The only mint I cannot seem to grow is spearmint. Planted in 5 different locations....it dies on me in sun or part shade. I have plenty of rain in south Mississippi. I keep trying. I love a challenge.😊

Love to find other mint lovers out there!
Because my garden was a sandbox when I started, I planted a little mint. I figured well, at least THAT will grow since it is invasive. And boy, did it ever grow!
But for those who are afraid it will overtake the garden, spearmint [mentha spicata] and all other types of mint as well have 2 ways of reproducing: Runners, which tends to stay close to the surface, and seeds. So to prevent it from 'migrating', we need to block both ways. To stop the runners, I made a deep bed [4X8] and planted close to the surface.
From mint I had bought, I made lots and lots of clippings and armed with a pencil, I dropped one little sprig in each pencil hole and watered. That's it.
When it reaches the edges, it just can't grow any more so it just comes back and fills the bed. I have to guide it back because it would easily fly over the edge of the bed and replant itself outside.
To stop it from seeding, I just harvest the heck out of it, never allowing it to go to seed. This way, I have no problems with cross pollination.
I cannot grow metha spicata in zone 4b Wisconsin. For this kind, I need at least a zone 5, but in Mississippi, you should be OK.
Mint seems to thrive on neglect. It seems that adding fertilizer makes them just gangly and weak. I love peppermint and mojito mint [Mentha Villosa], so those are the 2 I grow.