Planting in a clump - how close together?

[PrincessBuggerPants]

I frequently see claims you should plant certain plants in clumps of, say, three for 'effect'.

I have some salvias coming and I am growing some ferns too, and wondered how close together you should plant these when you plant them 'together' iyswim?

It depends on the variety. Salvias about a foot apart, each one should form a clump, which you later can divide.

I don't know about ferns.

Does it indicate what the spread is? That should give you a good guide.

I plant Gaura in clumps of 5. Quite close a couple of inches between each. Then I plant 3 or 5 clumps to get the repeat along the border. Advice from our local nursery.

I imagine salvia is quite similar.

Do you mean salvias for summer bedding, or the perennial ones.?

@expectopelargonium I bloody hope I have ordered perennials!

Thanks @actiongirl1978 I hadn't heard of Gaura before.

Just looked it up. I ordered Victoria salvia which is a 'perennial, grown as an annual'. WTH does that mean?!

I think Gaura is similar - semi perrenial. Mine is showing fresh shoots where I cut it down last autumn, but apparently sometimes it will regrow, others not.

I keep meaning to grow some salvia thanks for the reminder!