Impatiens is a tender annual and the first frost will blacken plants; the roots cannot survive northern winters.

The tubers need not be dug until a frost has blackened tops, that is until leaves are damaged/killed by frost.

Flowering continues until the first frost blackens the plants.

As with all dahlias, frost blackens its foliage, and its tubers need to be overwintered in a dry, frost-free place.

Cannas and dahlias are left in the garden until the first frost blackens their foliage.

One known step is to make sure that the storage procedure never begins until a good hard frost has blackened the dahlia tops.

The roots and tubers are easy to deal with, but the coleus must have cuttings taken before frost blackens all the garden foliage.

After frost blackens foliage, cut dahlia stems to 3 inches, carefully dig up, and cure in a dry spot for a day.

Dig dahlia clumps after a frost blackens their leaves, taking care not to break tubers.

Elephant's ear and caladiums can be dug up for storage over the winter after frost has blackened their foliage.