Protect Garden Plants in Winter 

In mild areas of New Zealand, tender plants can survive over winter outside with some protective coverings. But in cold or exposed areas even hardy plants may need some protection from the cold and wind. Evergreen plants and pot plants are at particular risk of damage, so pay them special attention.

Here are some ways of protecting your plants from the ravages of winter:

Feeding

Avoid applications of nitrogen-rich fertilisers late in the season, as they stimulate new growth that would be more susceptible to winter damage.

Drainage

Deal with drainage problems before winter. Wet soils will make young or shallow-rooted trees more vulnerable to uprooting in strong wind. Also, few plants like to have their roots in waterlogged soil for long periods.

Soil Cover

Exposed soil in wet winter conditions can result in leaching and loss of nutrients. Sowing winter tolerant annual plants (often known as green manure), such as mustard, in March, reduces leaching and provides cover for the soil. The young plants will hold nutrients until they can be dug back into the soil in spring.

Mulching

This can help maintain soil temperature, reduce compaction and prevent soil erosion due to heavy rain.

Wrapping

Protection can be used to insulate plants from cold or wind and should be put in place at the first sign of frosts. Wrapping can be made from materials such as fleece, hessian, straw and polystyrene. Take care to prevent sweating and possible rotting; protective covers should be removed when extended periods of very mild weather are forecast, but put back if the weather becomes cold again.

Containers

Site container plants in drier, sheltered locations. They can be grouped together for mutual protection. Don’t allow roots to freeze in containers by insulating them with bubble wrap or straw.

Structures

In late autumn check all garden structures to ensure they are secure and will not get blown over in windy winter conditions. Fences that are 50% wind permeable avoids turbulence and shaking of the fence so they are less liable to collapse.

Shelter

Your garden is a microclimate of its own. It will have warm places, such as the bottom of north-facing walls, and cold or wet places such as the shaded south side of walls or buildings. Choose plants for these positions based on the plant’s tolerance of cold and shade. Situate early-flowering plants such as magnolias and camellias so that they do not get the sun in the morning because rapid thawing of frozen buds can cause blackening and buds to fall off.

Windbreaks

Windbreaks will provide protection from wind and cold. The thoughtful placing of temporary windbreak netting or similar materials on well-secured strong posts will help in the short-term but additional planting such as hedges can provide longer-term, natural windbreaks.

Pests and Disease

Don’t ignore your dormant garden in autumn or winter. It may look like nothing is happening in the garden but lurking among the leaf litter, bark and dead twigs are the spores of diseases and the eggs of pests.

In frost-free weather prune and destroy dead, damaged and diseased parts of trees and shrubs. Then protect them from disease and pests using Kiwicare winter protectants Organic Super Spraying Oil and Organic Super Sulphur.

In autumn, your fruit trees, roses and ornamentals will benefit from a clean-up spray of Organic Super Spraying Oil and then Organic Super Sulphur . This will control fungal spores and insect eggs on the trees and prevent fungal and bacterial disease entering through damaged parts of the plants. Spray again after any pruning and throughout winter.

More on How to Protect Plants.

David Brittain
Kiwicare