Not necessary to most plants, frankly, though it depends on the plant - your passionflower might be better protected if you heap up some mulch round the base though, anything like garden compost or bark chips, anything at all, even piles of dead leaves will help. If your clematis is in the ground, it needs no extra protection.

I've put piles of dead leaves around the bases for years and haven't lost any (yet). I weight the leaves down with stones to stop them blowing away.

I deliberately leave fallen leaves round things I want to protect and I also put garden compost round them.

I use compost for mine.

Thankyou all for your help i have lots of leaves and garden compost so will get busy doing what you have all recommended Ann

My passion flower is growing up a south facing wall on the house and for the last 2 winters I've thought it was lost but it managed to shoot from the bottom again. I didnt realise it was the root that needed protecting, I thought the frost was damaging the growth above. Its growing out of gravel, so maybe I should get some warmth around its base? The Clematis Armandii on the same wall has suffered the same but bounced back - so maybe I should protect both of their roots?

Forgive me for stating the perfectly b...y obvious, Dawnsaunt, but if your plants got through last year and grew off the roots, the topgrowth having been killed back, I can't see what difference a mulch will make - it won't protect the topgrowth any better. In a milder year, I wouldn't expect Armandii to lose its topgrowth, it usually remains;-))

Hmmm understand what your saying, feel a right idiot now, lol.

Oh, sorry, you weren't meant to feel like that, Dawnsaunt, I was trying to be humorous... my apologies.

Ha ha Bamboo, I was only joking too, no need to apologise, afterall you are right and I always appreciate your knowledge.

Having re read what I actually said to you, I can see why you responded as you did - that's the sort of thing that should be said face to face, with a rolling of the eyes, laugh and a shove on the arm, not in print, doesn't come across with humour, does it.

I know exactly what your saying, you can't pull someone's leg easily in type. :-))))