You don't need to be an expert to select a good garden plant. Just give yourself enough time to choose carefully, so that you buy exactly what you want, not what someone wants to sell to you.

If you've set your heart on a particular plant, avoid accepting a substitute unless you're sure that it will be suitable. Have a reference book handy to check up on particular plants. Then you won't end up with a plant that will soon outgrow its allotted space.

Beware of vague staff and vague labelling. Ask the staff for the correct name of a poorly labelled plant - don't tell them which one you want, otherwise the plant may well miraculously become the very one.