11/03/2011 The Riverland Gardener, Tracy Jenner

Recent gardening fads and fashions have lead to an increase in the popularity of borderline hardy tropical-looking specimens and sun-loving plants, which require a little more tender loving care to get them through the winter months unscathed.
Even some so-called “‘hardy” plants can be vulnerable in colder regions, and exposed gardens. In any garden, all new hardy plants that are not fully established can be damaged, or killed in a prolonged cold spell, while new growth put on in early spring during a period of mild weather is vulnerable to scorch if the weather turns cold even for a short snap.
But the main threat to borderline hardy shrubs is winter cold, particularly cold winds that will freeze stems, and can penetrate deep into the soil during a prolonged freeze. In recent years we haven’t had much in the way of prolonged cold spells, but don’t become too settled — the weather only obeys Mother Nature, and changes quickly at times. The critical period for protection is from mid-December to the end of February, but be vigilant until the middle of March in this area, and if you have a more exposed garden.
Wrapping up
Vulnerable specimens can be given an enclosure made from windbreak netting that is lined with garden fleece, while not-so-hardy wall shrubs are insulated from the cold by spreading a sheet of fine-mesh netting over the plants, and stuffing it with insulating material, such as straw, or dry leaves. Alternatively, you could drape the plants with a double layer of garden fleece. Make sure you secure the netting along all sides to prevent it blowing about in windy weather.
Insulating the roots
Many borderline shrubs and climbers benefit from having their roots protected during prolonged cold spells by covering the surface of the soil with an insulating mulch of dry leaves or compost. This is particularly important while the plant is becoming established during the first few seasons after planting. Use netting to hold an 8-inch-deep layer of autumn leaves, or straw in place, or cover the ground around vulnerable shrubs with a thick mulch of garden compost, or even piles of hedge trimmings.
Protect against wind
Newly planted evergreen shrubs and trees will suffer during the winter months if they are not given adequate protection, especially in the most exposed spots. Being evergreen, they will continue to lose water through transpiration (the loss of water through the foliage), which they have to replace through their roots. Continue to water new evergreens if there is a prolonged spell of dry weather, treating them in much the same way as a winter container plant. Evergreens are also more prone to wind scorch during their early years, so protect exposed plants with a piece of windbreak netting firmly fixed to stout poles.
Insulating containers
You can protect plants in containers from freezing solid in winter by wrapping the containers in bubble polythene, and moving them to a sheltered spot. You can also cover the top-growth of susceptible plants, and those of borderline hardiness with a double-layer of garden fleece. Don’t forget to make sure that you leave access to water evergreen plants over the winter months.
Tracy Jenner, the Riverland Gardener, can be reached at tracyjenner@aol.com.