Posted: 01/03/2012 at 20:56
Hi, if it were me I would ease the plants out with the pots lying sideways - I wouldn't necessarily water them first ( presumably they should have some moisture anyway. After 4 years of growth, the roots will be well established and probably the root structure will be large enough to cope with the shock so if you cut any, I shouldn't worry too much. Once out of the pot, dig a hole which mirrors the size of the rootball and spike the surrounds of the planting hole to make sure the roots can get away in to the surrounding soil...especially if you have a heavy clay soil. I would also tease the roots outwards if they're starting to 'ball' around the pot, perhaps trimming some of them prior to planting.
I would also apply a general fertilizer either in the planting pit or as a top dressing after firming in just to help the plant settle in after the shock of being transplanted, and water well. The clematis will be more resilient than you think if it's a montana or armandii and the honeysuckle is a toughie too so don't worry too much - just be as careful as you can in getting them out of the pots but not overly cautious. Personally I would prune down the top growth too after replanting by about a third (pruning down to just above a bud or leaf node)
Spring is the ideal time to move them as they're still pretty much dormant but you can transplant in summer too bearing in mind that you will need to water more thoroughly and more regularly over the months after planting just to make sure they've taken and don't suffer their roots becoming desperate for moisture. Autumn is also a great time (as per Spring) as the earth is still warm and moist.