Frost resistant

Frost hardy [ Horticulture ]	Dictionary of botanic terminology - index of names
Synonyms: Hardy, Cold resistant, Winter hardy, Frost tollerant.

Plants that are able to survive winter frosts without damage to their leaves (ie Evergreens), stems (ie succulents) or damage to perennating organs like dormant buds or roots (ie Deciduous plants).

The term 'frost hardy' is often misleading because of the degrees of frost (i.e. light frost vs. hard killing frost) in fact there is not an universal standard to define frost resistance of plants according to their ability to survive degrees of frost. Frost hardines is very much relative to geographic areas.

Hardy plants can tolerate frost but vary in the severity and duration they can survive.
Here a common classification of plant hardiness:

Frost hardy plants can stay alive even when temperatures go down to -5°C
Fully hardy plants can cope with short spells as low as -15°C.
Half-hardy plants cannot tolerate frost can survive when temperatures go down to 0C.
Tender plants maybe damaged by low temperatures below 5°C.

These are general guidelines because if a plant is in a protected or sheltered spot it might well survive lower temperatures.

See also: Cold resistantance

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994