You want your plants to survive our British climate so it is worth understanding the hardiness ratings. Plant hardiness is based on the lowest temperature that a plant can normally withstand during  winter.

Categories of Hardiness

• Hardy plants are those capable of coping with temperatures as low as -15º C.
• Frost-hardy plants tolerate temperatures down to -5º C
• Half hardy plants should survive in temperatures above zero.
• Frost tender plants may be at risk below 5º C.

Hardiness Zones

• The USA is so large and covers many different climates that it relies on Hardiness zones for horticulture and gardening.
• These hardiness zones are geographically defined areas where temperature  will dictate what plant life is capable of growing.
• Zone 1 is -50º C,   Zone 8 equates to -7º C   and Zone  10 is zero.
• England is generally in zones 7 – 10 Scotland is cooler and Ireland warmer due to the warming effect of the gulf stream.

Plan Your Hardy Garden

• Frost will run or fall down slopes and collect in ‘frost pockets’. Be careful what plants you put at the bottom of slopes.
• Frost on young buds may not hurt but a rapid thaw caused by spring sunshine probably will. Camellias get frost burn and loose their buds if facing an easterly rising sun.
• Your garden will have a series of micro climates so map out those areas that are suitable for special plants.
• Allow your plants to acclimatise. Sudden drops in temperature can be more deadly than cold.
• Be aware of heat hardiness as some plants will not survive hot temperatures.
• Fertilizer hardiness is an issue not fully understood so watch out for sufferers.

Tactics of Hardy Plants

• Hardy herbaceous plants allow the foliage to totally die back in autumn. The roots remain viable under the soil and regrow in spring.
• Some hardy plants allow the stems and leaves to fall on the root crown to create a warming mulch until next spring.
• Sappy growth is a target for frost so hardy plants stop growing in summer allowing the twigs to toughen up. Do not feed plants with high nitrogen feed in late summer if you want them to remain hardy.
• Trees and shrubs take the sap back down into the plant and branches so that twigs are too dry to be damaged if they freeze.
• Plants will grow less well and be prone to winter injury if the soil is heavy, wet, of low pH or low fertility, or in general not suited to the plant.
• Some plants grow more sugars in summer to sustain them through cold winters.
• Thermal insulation from snow cover helps plants survive normally deadly winter temperatures

The Hardy Plant Society

• The Hardy Plant Society is a UK charity that was formed to foster interest in Hardy Plants.
• The Society informs and encourages the novice gardener.
• There are 40 regional groups so you can join one near you.
• They have specialist societies for Geraniums, Peony, Pulmonaria, Variegated plants and Ranunculaceae

Sources of further information

It is hard to address the ‘question asked by everyone with ambitions to grow hardy and semi hardy tropical plants in the UK’.

The British Fuchsia Society has an official list of fuchsia plants that are capable of being over wintered in the garden