Sorry, Jennyfer, but you will have to look them up, or examine the labels on the plants to check the height and spread details. There's no single rule for planting - not much point in saying a foot apart if you have something that gets 4 feet wide next to something that gets 6 feet wide - unless you're planting a hedge. Only thing I can tell you is, once you know the spread of a plant, let's say its 3 feet - that means straight across, so you'll need 1.5 feet either side of the main stem, and at the back and front too.

okay, thankyou :) I had better get my plant books out and get busy then :P