Hi, I think this was answered on question 17329

This has to take the prize for the most asked question this year! They might have died but you can wait and see - if no growth by end of April, they're ex cordylines.

I think many have suffered in the colder than usual temperatures, they are generally ok in anything down to -10 once established. My 15+ year old specimen is about 25ft in the sky and no damage at all thankfully.

I have three cordylines which have suffered from the frosts of the very severe winter. Yesterday I asked the advice of an authority on homoeopathic plant care. On his recommendation I have given a homoeopathic remedy called Carbo veg in the 6x potency. This remedy is possibly available OTC but if not then certainly from a homoeopathic pharmacy - Helios or Ainsworths. I would think approx £5.00. A pillule [pill] should be put into a jug of water and poured onto the soil around the base of the plant. I only this did this yesterday but the leaves have already 'lifted'. Now, I just have to wait... At very little cost it is worth trying.

ALSO for information: I often use the Bach flower 'Rescue Remedy' when any plant looks in need of some rescue i.e. when moved ... and the roots have been disturbed... google Bach flower remedies for more information.