Planting shrub roses in triangles or not

[new gardener 1052]

Good evening folks
I have some roses growing alone but I'm reading a book on growing roses and it suggests planting roses of the same variety in groups of 3 in a triangle fashion,

It says plant between 18"-24" apart I would have thought this would stop air flow and sunlight through the bushes,

Anyone have any thoughts on this?

[Thelma Sanders]

If you want what looks like large bushes, then, if you have chosen slender growing varieties, then it makes sense to plant 3 together. However in a small garden and for stronger growing varieties, then single roses still work well.

I have planted a few together, and some separately both ways seem to work

[new gardener 1052]

At the moment I'm growing lady of shalott / Thomas a becket & Harlow Carr

[Briony]

I think that in theory, with some old fashioned roses, it's to create that 'massed' look of one giant rose that you see in gardening magazines. I bought an Isaac Pereire last year and the seller suggested this, but I had then same concerns as you so I'd be interested in knowing, too.