Mint yellowing

I've been growing mint for a few years and it's always the same story. It starts very well until summer when it begins to turn yellow/brown.

This is the current situation and eventually there will be no green leaves.

I recently fought with an army of aphids which spread on most of the plants. Repeated use of neem oil and horticultural soap eliminated almost all of them.

The location is in full sun and I tried both keeping the area well watered or rarely watering without seeing any difference.

The only place where I could try relocating some would almost never get direct sun.

Any ideas what could go wrong? I've seen similar situation with the mint from neighbours where they planted other varieties in identical conditions.

 

Had one just like that. They started yellowing at the base but retained their green tips. I always assumed it was an evolutionary trait to send all those nutrients to the plants top where the sun shines brightly at the cost of the lower leaves which wouldn't get a lot of sun anyway.

Now I have a different mint type and it grows lovely.

 

Try cutting some of it back hard, it goes woody at the base very quickly.
Is it in a container, only it's pretty greedy.
I grow it in an old water tank with very little drainage, in shade, and water and feed it when dry.
It still goes yellow and woody, I think I have spearmint but lots of others to try.
Digging some up and replanting the roots should give you some fresh new green shoots.

 

That would be ok if yellowing stops. In my case it eventually takes over the whole plant.

It's not in a container. I attached another picture. There are concrete blocks around to stop it from spreading and it can go as deep as it needs.

The plants are turning woody and even the small ones are now yellowing. Is your suggestion to remove the old roots every year to get new shoots? I had a single plant in 2019 which spread over time and there is still enough space around.

There is still space left for it and I could do that now with the smaller ones which are unlikely to be get more healthy over time. Does it matter how old is the plant from which you split the roots?

 

I grew a plant inside a container. Worked well for 2-3 years, and after that they started growing flimsy and yellow. After planting it outside and giving it some care (cattle droppings and horn shavings) it started flourishing again.

So my next guess would be it doesn't get enough nutrients. Sure it is planted in real soil and gets real sun. But there is probably not enough exchange of nutrients with its surroundings. Try to dig it up, cut it in half, then loosen the ground and add some blood, fish and bone or real compost before putting it back in. If that doesn't revive it, I don't have any more ideas

 

If you leave mint to it's own devices it spreads outwards and dies back in the middle.
Its something quite a lot of perennial plants do. The best growth is always around the outside, as the plant moves in to new ground.

If it's contained it can't do that so you need to dig it up refresh the soil and replant the best looking roots.
Best done before new growth starts in early spring.

I do it every couple of years in the tank, but even then I fertilise in spring.
Mine is also going woody at the base so only using the tips now.

 

Thanks for the suggestions!

I'll test this year by replanting some roots and adding fertiliser.

Two questions:
- for the roots, is it ok to dig out the plant and cut everything that's above roots before planting again?
- what's the most important part from NPK for the fertiliser? The suggestions vary in the ratio between them.

 

You only need good strong roots, the top growth can be cut off.

High Nitrogen feed would be best, but in good soil it should be ok without feeding too much.