For the UK there are essentially two styles of palm... those with broad fan shaped leaves and those with long feather-like leaves. Although some palms from warmer climates will grow in the UK they will grow an awful lot slower, some requiring a good soaking of heat to kick them into action. This needs to be borne in mind when selecting and positioning palms. Palms from temperate climates will grow much faster. Palms also have a predictable growth pattern – straight up. They don’t wander around like shrubs and trees. This makes them very easy to manage.
A lot of palms are graded for cold hardiness. This is very misleading because there are different types of cold and also palms which are grown abroad and imported by superstores will have a much lower tolerance to cold.
A sudden onset of a nasty minus figure which thaws out the next day is far less damaging that a long lingering freeze which is just below or above zero, that is why places like Florida can grow a greater variety of palms than the UK, essentially because it has good warm days to compensate for harsh freezes. This helps palms recover from stress. In the UK Winters are wet with very little light and no warmth. Palms do not like these conditions so can suffer damage quite easily, especially if young. Rain followed by a harsh freeze can be very damaging as the water freezes near the core of the palm and can induce rot killing the spear.
I find the worse time for palms is March and early April. Warming UK day and night time temperatures can start to kid palms into sucking up water again. Then they are hit with just a mild frost of say -4c and then 'bang' their saturated cells burst and leaves blacken off and the plant may even die. If your plants reach the third week of April then you can rest for another season :)
A palm should be planted out in the Spring. Care should be taken regarding position. Remember these are trees and will expand their trunks to quite imposing proportions as they grow. A lot of plams do not like to be dug up again and the stress of this may kill them. If you must dig one up do it in Autumn or very very early Spring (like most trees or shrubs) and strip of a lot of the foliage so it does not dehydrate moisture through the leaves.
Some palms can completely defoliate during Winter. However if a good hot Summer follows they will usually recover. If no hot Summer (which is usually the case in the UK) then they will probably die off.