Frost, or more specifically, the alternate freezing and thawing action of frost, can destroy plant cell walls which usually affects young plants or new, unhardened, growing tips. Flowers, buds, shoots or leaves of hardened plants may also blacken or become distorted and in severe frosts the bark of woody plants can split.  Damage is more likely to be seen on tender plants, particularly those what have put on growth in late autumn or early spring but can also be seen on variegated or gold leaf plants.