Leggy/Woody Container Grown Mint

[Susan BBPM]

I don't have much growing mint in containers. Or at least, I do .... but not for long!!

It starts out lovely and green and lush. But very quickly it starts to get woody and sparse.
Last year I assumed it was because the container wasn't big enough. I potted up two plants - one into a slightly larger container and one into a HUGE container. They didn't recover. I bought a new mint plant and put it in a huge container. It did well for a couple of months then the same thing happened.

It's very possible I let it dry out a few times.
I didn't pick any - so it wasn't getting pruned.
It was potted in good compost with soil mixed in.

I tried giving it a 'hair cut' and pruning it right down, but it didn't make much difference. It never grew back nice and lush.

What am I doing wrong?

And a slightly different issue - my lemon balm (same family) is also in a pot, but I notice the roots have grown out the bottom and into the ground. Should I panic? How do you eradicate unwanted mint?

 

[AshyLlama12]

My Mojito mint plant in a pot is doing the same thing, Leggy with sparse leaves. I can’t see anything particularly wrong with the plant but it doesn’t seem to be getting better or worse

 

[Oliver Buckle]

When it does that to me I tend to think of it as the plant is getting old and take cuttings. I go for the outside edge of the pot to get a new bit of root, that is less disturbance to the old plant as well if it doesn't work and I have to come back.
There is a good article about mint on the gardener's world site.

How to grow mint

All you need to know about growing, harvesting and storing mint plants, in this step-by-step Grow Guide.

www.gardenersworld.com

You can skip the first bit.

 

[Susan BBPM]

When it does that to me I tend to think of it as the plant is getting old and take cuttings. I go for the outside edge of the pot to get a new bit of root, that is less disturbance to the old plant as well if it doesn't work and I have to come back.
There is a good article about mint on the gardener's world site.

How to grow mint

All you need to know about growing, harvesting and storing mint plants, in this step-by-step Grow Guide.

www.gardenersworld.com

You can skip the first bit.

How long should a mint plant last?

In my case, I'm buying a lovely potted Moroccan mint out of B&Q and potting it up into a large container with john innes, compost etc. It does well for a couple of months - filling the container very quickly, then goes woody.

I mean, surely it should last a season or two?

 

[Tuilly]

I am growing it in a Water container and this doing well.

 

[DirtMechanic]

We grow catnip. Outside in the garden it gets full sun and reasonable drainage, but as a context of the garden generally it gets moisture at least once per week. It grows fast and will be mature in one season, die back over winter and unless we pull the plant to make catnip toys for Christmas it will come up again next year. When one uses a potting soil and the plant seemingly succeeds for a couple of months but then wanes, your nutrition has run out of the potting soil. You need to fertilize. Plants that get leggy late but have enough sun probably have their feet in an abundance of Phosporous and if they are turgid then probably it has enough Potassium too. My guess for the needs of a leafy fast growing plant is a fertilizer with a higher Nitrogen content. They get long and woody naturally as they age but should be bushy generally unless they are starved.

 

[Oliver Buckle]

How long should a mint plant last?

In my case, I'm buying a lovely potted Moroccan mint out of B&Q and potting it up into a large container with john innes, compost etc. It does well for a couple of months - filling the container very quickly, then goes woody.

I mean, surely it should last a season or two?

TBH I really don't know how long it could last, but yes, more than a season or two. Growing wild it will self propagate with spreading roots, so it could virtually live forever.
If you haven't already now is the time to cut it back to the ground for new spring growth. I would do what I suggested , taking cuttings, then cut it right back hard and see how it comes. I think usually it is down to it having used up all the nutrient. When you tip it out of the pot it is often completely root bound, so although I make up a nice mix of my compost and farmyard manure it does use up what is in a pot quite quickly.
When your B&Q mint is at its prime tip it out and see if it has filled the pot with roots. If it has take a couple of inches of thick white root from the outside edge and pot it up separately. If it is sending up shoots already, great, but it will nearly always work even if there is no sign of them. Then pot up your parent plant into something where it has room and new soil and give it a haircut to stop woody bits and encourage soft growth. It will at least save you spending down B&Q, and if you do some extras in case some fail, and they don't, they make nice little gifts.