Mike Lyle wrote:
John Edgar wrote:
Does anyone know how to fastigiatise a cotoneaster?

On the whole, I'd assume it was impossible: if a plant has a
spreading habit of growth, then it'll spread. You could tie it up,
but the ends which came out the top of the tie would spread.
Fastigiate forms are genetic, not trained.

Perhaps somebody will prove me wrong, of course.

It occurs to me that you could try a form of topiary: bundle up a
well-grown plant in chicken wire, and regularly prune back the
side-shoots which came out. You'd need to prune very cleverly before
bundling it up, of course; and I think there'd be a great risk of
death by disease and shading in the crowded centre. Even if it
worked, I don't think it would look truly fastigiate, and you
wouldn't get many berries; but this could give you the overall shape
you want.

--
Mike.