Thanks to global warming, tender plants from milder regions are now finding our gardens quite hospitable. But frosty snaps can wreak havoc on those half-hardy treasures if you don't remember to run out the night before and cloak them in horticultural fleece, bracken or straw. In fact, it's not so much the frost that destroys some plants, but the rapid thawing afterwards by the morning sun. Gently directing a very fine spray of water on top of frozen foliage promotes a more gradual thawing, and the cell-walls are less likely to burst and cause the leaves to collapse. This tip comes from Brian Wood, of Murphy and Wood Garden Centre, Cabinteely.