Determining if a plant will be hardy enough for your garden, or wherever you intend planting it is far from an exact science. On the plant side it's not too bad as the hardiness of most plants has been reasonably well established. The trouble is knowing, not just the climate of your geographical area, but also the microclimate of the planting area, for example, aspect, exposure to sun, wind, rain, soil condition and proximity to a wall or if there is shelter from a tree overhead.
We've put together a guide, that doesn't try to be too specific making it inaccurate, or too vague to be of any use at all.
Included in each plant description there is a one of the terms - Hardy, Half-Hardy and Indoor/Conservatory. Below is a brief outline of what is meant by each term.
Hardy - Plant should be fine in all but the worst of situations, only prolonged very cold weather or exposure to strong wintry winds should be of concern.
Half Hardy - Plant will benefit from a cosy sheltered position throughout winter. If potted consider placing undercover or in a greenhouse if possible.
Indoor/Conservatory - Plant should be considered an indoor or conservatory plant. Will be fine outside during the warmer months from May to September, but must be inside for winter.
There is much you can do to improve a plant’s hardiness. Here are some suggestions for less hardy plants:
• Plant out in a sheltered spot, maybe near a wall or fence or under a tree
• Generally well drained soil is nearly always preferable to help to reduce freezing in winter.
• Mulching is another great way to help minimalise the soil freezing in winter.
• Protecting the plant is often achieved by wrapping the entire plant or in cases the crown of a plant with Hessian or horticultural fleece.