Tuck up your garden for winter
Alice SpenserHiggs offers some survival tips for the garden in the cold season
THE garden has experienced its first cold snap and, now that winter is a reality, it is a good time to revisit those winter gardening tips to minimise cold damage.
Preventing frost damage and dealing with its consequences is likely to be a first consideration.
Kirchhoffs’ Marlaen Straathof says young, actively growing and flowering plants tend to be particularly vulnerable to frost, especially when cold temperatures occur after a warm period.
Watch the weather reports and if a cold front is predicted take preventative action, like covering young or tender plants with frost cloth that can protect plants at minus zero temperatures.
A very light, easy to manage frost cloth is available from garden centres and nurseries often throw it over beds of frost-sensitive plants in the afternoon and remove it the following morning.
When protecting a young shrub or tree one can make a frame of sticks, which is placed around the plant so that the cloth does not touch the leaves.
Make sure there are no openings from which heat can escape. Do not gather the drape around the trunk of a tree because the aim is to trap heat being radiated from the ground. The best is to arrange the drape so that it touches the ground at least as far out as the drip line.
Straathof says that cold air settles downward and can collect at the bottom of a slope, while hot air rises. Any plants in pots should be moved to higher, sunnier and sheltered areas. If plants can’t be moved they should be protected with frost cloth.
If frost damage has already occurred don’t be tempted to cut away the blackened, dead leaves.
“The dead branches and leaves protect the plant from further damage,” says Straathof, who warns that cutting back could also stimulate new growth that could be vulnerable to late frosts.
“The frost-damaged leaves and stems will continue to help trap warm air within the canopy of the plant. The damage often is not as bad as it looks and new growth could come out of tissue that appears to be dead. In spring, dead wood can be pruned out.”
However, if the frost has killed tender annuals and perennials dig them out. Soft-stemmed perennials like arum lilies that were flattened by the black frost are an exception and will sprout again in spring, but there are others that will not recover.
In winter, plants should be watered earlier rather than later so that the leaves can dry before temperatures drop from 4pm.
Don’t overwater in winter but also don’t let them dry out completely because droughtstressed plants are most vulnerable to frost. Well-established flowering plants only need to be watered once, possibly twice a week. Annuals that have been transplanted may need more water but as soon as they are established the watering can be cut back.
Although growth slows in winter, plants should still be fed because healthy plants are more tolerant of cold weather. Flowering plants in particular need feeding to continue producing flowers.
A liquid plant food is more quickly and easily absorbed by the plants. Do not use a nitrogen-rich food for winter or spring flowering annuals because this could encourage soft, sappy growth.
Rather use a feed formulated for flowers and fruit that contains higher amounts of potassium. In the N:P:K formulation of a fertiliser, potassium is represented by K.
Nitrogen-rich food can be used for green leafy vegetables such as spinach, lettuce and cabbage.
Keeping the compost heap going is an essential winter activity. The microbes will continue to be active if they are kept going with a balanced diet of brown material (carbon) such as dead leaves and green material like lawn cuttings, pruning’s, vegetable and fruit peels. Shred or chop the material as finely as possible — this not only speeds up decomposition but forms an outer insulating layer.
Another way is to use a commercial compost activator like the Kirchhoffs Compost Maker.
At every 20cm sprinkle the Compost Maker evenly over the surface and cover with a fresh layer of material.
In summer the best place for a compost heap is in the shade, but in winter in cold areas the heap will decompose quicker if made in a sunny part of the garden.
In dry winter areas the compost heap needs to be watered about once a month because the microbes need moisture to survive. The heap should be moist but not sodden
Winter flowering annuals that like the cold, such as violas, primulas, Iceland poppies and cineraria, can be planted out even in very cold weather. It is less risky planting winter annuals in cold weather than summer annuals in very hot weather because the roots dry out quicker in summer.
Prepare the soil well using lots of compost, water and let it stand for a day before planting so that the soil is moist but not sodden.
Left, pansies and alyssum ... continue to fertilise flowering annuals in winter so that they keep on flowering. Above, petunias in pots ... container-grown plants that are kept in sunny, sheltered areas are less likely to be affected by frost.