2 x 50m rolls, 1000mm wide, large bubbles are £19.99 per roll on ebay

http://www.ebay.co.uk/itm/BUBBLE-WRAP-ROLLS-CHOOSE-WIDTH-300mm-500mm-750mm-/201198688040?pt=UK_Packaging_Materials&var=&hash=item2ed8605728

I wouldn't have expected them to be that tender. But I would think that bubble wrap was just about the worse thing to use in place of organic mulch.
Check out http://www.alstroemeria.co.uk/index.php/plants/growing-guide
If that's what works in Gloucestershire then it should work in Dorset.

Thank you both for the advice.

Badfish: there are quite a few firms that offer 50 metre rolls. I hoped to find one roll of 1000 metres (cheaper, surprisingly)

Urbanite: We usually use leaves etc when we put the Alstroemerias to bed and we have not lost one yet. This year my Other Half thought he would save time and trouble with bubble wrap.

I think I'll contact lovely Viv Marsh of Viv Marsh Postal Plants where we bought the plants.

Mine are blooming beautifully right now...admitedly on much shorter stems but still beautiful. I have had mine for about four years and have come through two very severe winters unharmed. Have I just been lucky?
I was advised to pull the dead flowering stems off from the mother plant as, I was told, this encourages more flowering. Is this true?

Under plastic, the ground and plants will remain wet all through the winter and very likely to rot. An organic mulch will get damp and then dry off somewhat depending on the weather and the plants will be much healthier.

You don't need to put any bubble wrap down, trust me they always come back, I have large drifts of these in a clients garden and for the past eighteen years they have thrived and this is a garden in the high peak district.

Johnp58: Yes we are still picking flowers with more to come. We live in the so-called sunny South but we do have the odd severe frost. We want to be prepared!

Am contacting Viv of Viv Marsh, Postal Plants, to ask for his advice as we bought all our plants from him, as a result of your comments.

I meant 100 metres! Why can't people sell in good old feet and yards!!

Will be interested to hear what Viv Marsh advises. I only have a few, and was thinking of putting straw over them, if anything. But I do believe, and am convinced by others' comments above, that they are much hardier than we think! I've never protected mine yet (East Coast of Scotland) and haven't lost any. So I probably won't bother this year either....just laziness really! My instincts tell me that bubble wrap isn't a good idea....it created so much condensation in my greenhouse that everything rotted, so I wouldn't use that myself.

I think Viv must be away as he is always so prompt in his replies and I have not heard from him as yet.

Cottagekarer: Our overflow of plants ends up next door and our neighbour always insulates her greenhouse with bubble wrap. Everything is fine there: haven't lost anything......yet!

We normally cut off the Alstroemeria stems before "burying" the remainder under masses of leaves. The latter must get damp...?

Yes, you're absolutely right of course, although leaves would 't exclude air the way bubble wrap will....

I wouldn't go down the bubble wrap route in my greenhouse again....I know loads of people swear by it, but it didn't work for me...and it's SO damp here now, in fact, it's swamp!

I'm sure you'll hear from Viv in time! :)