Over-wintering Frost Tender Plants

Keen gardeners everywhere will want to try in their gardens plants which may not always come through frosty winters. A good example of such frost tender plants is Cosmos atrosanguineus which has velvety, chocolate-scented, deep purple-red flowers. Planted in spring, it will flower for months until well into the autumn. At this time of the year you are faced with three choices: dig it up once the foliage has died down and dry it off in a frost-proof shed or room like a dahlia; leave it where it is and mulch it with leaves, bracken or straw to a depth of 6-10cm/2-3in until early spring; or leave it alone and let it take its chance, I did the latter last year and my plants withstood -10 °C for several nights, and still grew away in the spring. But I was testing for hardiness in my garden and so had an incentive for taking the risk.

Depending on where you live, some of the plants that you might consider protecting for the winter are: agapanthus, cautleya, Commelina coelestis, some crocosmias, some kniphofias, Melianthus major, nerine, penstemon hybrids, phormium, Salvia ambigens, schizostylis and zauscheneria. Recent mild winters have allowed most of the above plants to come through the winter without protection in my garden. Site and soil will make a considerable difference even in colder localities. A basic rule might be to protect as for the cosmos above in the first winter at least.