We had this problem a couple of years ago when I bought fifteen box plants to put round an area of lawn. For various reasons mostly related to DH not getting his finger out, coupled with the weather, we didn't get them in for quite a long time. They were already outgrowing their little pots when I bought them and, if I'd had space, I would have done just what Pompa said and heeled them in, but I just potted them into slightly bigger pots and left them to their own devices. They did very well when we eventually got them in. Last year I got stuck with three bare rooted verbena bonariensis which I bought because DD said she would like some, and then could not make up her mind whether she actually wanted them or not. I heeled them into a small bit of spare ground where they were quite happy waiting for her to make up her mind, but eventually had to dig them up and find them a permanently home in my flower bed. She had the cheek to say a couple of years ago "I might have my (MY
) plants this year!" I should cocoa!