Does anyone know

This is just a theory, but I wonder if some plants sometimes go into a kind of dormancy. Seven years ago DD bought me a day lily, which I grew in a pot. It flowered for a couple of years and then it stopped and refused to flower, despite being repotted. When we moved, I was almost tempted to leave it behind, but I brought it anyway. It still didn't flower but I took it out of the pot, put it in a corner of the garden and left it to itself. This year, four and a half years after we moved, it is full of flowers! I believe agapanthus can behave similarly. I'm sure someone more expert will give you better advice .

Perhaps they need to be neglected. I used to leave both lily of the valley and cyclamen in Oxon to get on with life on their own, including letting them dry out. They thrived.

I suspect neglect could be the way. Our garden became over run with LOV, we cleared it eventually and planted up a couple of tubs, they have never thrived in the tubs.

thatbags..... Are they still there? I could steal them.

Sometimes plants just do this ( depressed?) and then they spring back into life.

I transplanted some Lily of the Valley from a friend's garden (she was moving) about seven years ago. The blighters have never flowered and I can only assume that our soil is too alkaline.

I'm going to dig them up and move them to a different border and see what happens. DH keeps banging on about soil testing but I really CBA these days.

This is some information about their growing preferences. Convallaria majalis is a plant of partial shade, and mesophile type that prefers warm summers. It likes soils that are silty or sandy and acid to moderately alkaline,[11] with preferably a plentiful amount of humus. The Royal Horticultural Society states that slightly alkaine soils are the most favoured.[12] It is an Euroasiatic and suboceanic species that lives in mountains up to 1,500 m altitude.[13]

One of my friends has a lovely bed full of Lily of the Valley, been there for years. It is at the side of her house, narrow area between her and neighbour, poor soil and shaded most of the day, and she doesn't do anything to care for them. They have a large honeysuckle growing in same space and they all thrive together. So poor soil and shade seem to be the way to go.

We have the same problem ......

Mine grow beautifully along the paving stones in the path, in the shade of a Larch. They refuse to grow anywhere else, which is a pity because they risk being trodden on!

DH was given a small clump about 15 years ago I duly planted it and for 10 years it didn't grow a bit.

Then 5 years ago we cut back all the shrubs,so it was in full sun and it took off like a rocket,the clump is now about 5ft x5ft and every may has literally hundreds of blooms,vases of them all over the house.

BTW our soil is alkaline heavy clay.

I had a few lily of the valley under some conifers in my last garden and they were a bit hit and miss as regards flowering, but in 1971 we lived in Belgium with a large wood bordering our houses which was full of lily of the valley. The scent was unbelievable. At that time I didn't know what they were, but I used to go walking there with our neighbour's mother who was a lady in her nineties (so we didn't walk very far or very fast!) and she told me liked to walk there because the scent took her back to her childhood in Norfolk .

A front garden near me has a limestone wall at the pavement edge retaining a sloping bed. A patch of lily of the valley thrives right up against the wall, some of it extending into the joints between the blocks and even poking out under the top layer of them (about 8 inches deep) The wall faces south, so I would have thought it too hot and sunny for them, but the thickness of the stone must make it coool and damp in behind the wall, and they will be in a slightly alkaline environment against the stone.

I think I shall try some in my rockery!

I think they're just temperamental. We had a garden in Doncaster where they came up everywhere, between cracks in paving, base of house walls, just everywhere. Attempts to establish them in 3 subsequent gardens have failed completely. I have a few in current garden which were dug up from a rampageous patch in in-laws' garden about 10 years ago. They're hanging on but only just...

Having looked at where ours are planted, I have cut back the over-hanging shrub (not before time), just loosened the earth around the plants, and given them a drink - they look better for that, or perhaps that is my imagination, I must continue to nurture them, I think and not take them for granted. Next year, perhaps?

They are taking over our front garden and going into my neighbour's side. She had a bit of a whinge but I am not taking any notice.