welcome fenn i would have thought anytime as long as the ground is not frozen or water logged.others might tell you different. good luck.

Hi Fenn and welcome to GoY - where are you on the planet? It does make a difference :)

You can't go wrong planting most things in spring as a general rule of thumb although many bare root plants like to go in in late autumn!

Generally much better to plant bare rooted shrubs and trees in autumn, possibly a little late now but until we know where Fenn lives difficult to give an accurate answer.

With a few exceptions, the best time for planting of permanent subjects is September/October, if you're in the northern hemisphere. Other plants, such as Ceanothus, are better planted in spring, from March onwards.

Whenever you choose the time and wherever you plant it, be sure that the base of the plant is in the cool shade for the most part. Clematis plant roots like to be cool and moist. Planting a nice hosta near its base is what I have done to accomplish this. I've always planted clematis in the spring, reason being thats when they became available at the local garden store.

As soon as possible after purchase! Generally speaking plants are sold at the right time for planting. Although it sometimes feels like it, garden centres don't go out of their way to sell plants when they haven't a cat in hell's chance of surviving. ?

Well good old fashioned nurseries sold, and still sell, their shrubs/trees in autumn. Garden Centres sell them in spring because it is when folk now believe it is good to plant and also because by the end of August most of them have converted to selling all things Christmas.