Hi, welcome to GoY, is there any chance you could add a photograph please, it would make identification much easier?, are you sure it's a grass ? as far as I know, the only bulbous grass is bulbous bluegrass, but that is dormant in summer, and doesn't get that tall, neither does it have purple/pink flowers. I have a feeling that it might be Verbena bonariensis, but this isn't a grass, Derek.

Hi, actually if it is bulbous, it can't be that either, but it's the only thing I can think of that could be described as grass like, with purple pink flowers summer to autumn, Derek.

Bulbs? rhizomes? tubers? all get mixed up. Yes, a photo would certainly help. The only thing I can think of is Pink Pampas Grass (Cortaderia selloana ‘Rosea’).

I wonder if it's an allium eg A sphaerocephalon. that sort of fits the description.

do the leaves smell of onions?

Pennisetum setaceum has purplish pink flowers throughout summer and reaches around 4 feet - it has the common name of fountain grass, though that isn't reliable because that term gets used for other grasses too. However, it depends where you live, because technically its not hardy in the UK. If you're near the coast or in the west country, or your garden is particularly sheltered,it might be that. Otherwise, can you describe the flowers in terms of shape, if you can't post a photo?

It could be a dierama (angel's fishing rod)

I think you could be right Andrew, never thought of that 1, Derek.

Agree with Bamboo, it sounds just like Pennisetum setaceum . . . lovely grass.

I thought about Dierama too, but that doesn't flower all summer.

Perhaps you could google the suggestions made above, Robert, and see whether the pictures match your plant. Then you could tell us which it is! It does sound a lovely plant to have.

Well we have a lot of possibilities here. One guess is as good as another. Giving actual advice is nearly impossible without know exactly the plant in question. A nice clear photo would certainly help.