Fighting frost while still having a beautiful garden
Tired of losing money on plants that don’t survive frost and bitterly cold winters?
There are steps you can take to remedy this when fighting frost!
Although planting tough, cold-hardy plants is the most important step to success in difficult climates, good garden management plays an important role in fighting frost too.
Protect the defenceless
Use frost cover (also called horticultural fleece) to protect young trees and shrubs that are still to become established. The cloth, which is available from nurseries and home stores, can be left on the plants as it allows air, light and water through but protects against icy winds. Many newly planted plants in cold areas need this protection for at least 3 – 4 years before you can relax.
Keep plants healthy
Preventative and timely treatment against pests and disease will keep your plants healthy and stress free, with a better chance of surviving winter and fighting frost. So if you see any infestations of insects or fungal diseases, deal with them promptly.
Fertilise correctly and regularly
The garden should be fed regularly with a balanced fertiliser during spring, early summer and late summer. Early autumn fertilising should not be with a nitrogen-rich fertiliser, which will stimulate soft new growth, but rather a fertiliser with a high potassium content to ‘ripen’ vegetative growth and harden the plants’ cell walls, which will help them to better withstand cold and disease while fighting frost. Winter-feeding of leafy vegetables and flowering annuals carries on monthly and should be with a soluble, general purpose product.
Leaf cover diminishes damage
With winter approaching, don’t prune evergreen plants that are at risk of getting damaged by frost, and don’t remove any dead plant material like old flowers or leaves from perennials that have finished flowering. Pruning can encourage new growth in mild, sunny weather that is especially susceptible to sudden frosts.
Lay a mulching blanket
Organic mulches like coarse compost, bark chips, lawn clippings and fallen leaves spread over the soil (not too thickly) will protect root systems and keep the soil moist and warm. Move container plants you are worried about to a sheltered spot, pack them close together and cover them with hessian or grass.
Wet soil cools down slower than dry soil and stores more heat. Irrigate at daybreak before the sun’s rays reach frozen plants. Heavy, drenched clay soil and bad drainage, on the other hand, is deadly when heavy frost arrives. Condition these soils with lots of coarse compost and even some coarse river sand to loosen it and improve the drainage.
Beat the winter blues!
Winter and spring bulbs that can still be planted now need cold to make them sprout, and can be used in abundance. Also embrace seasonal colour – most winter and spring annuals and perennials from the Northern Hemisphere will survive frost and cold, and there is a good range of them to plant now. You can also plant some of your own indigenous frost fighters. The good news is that some of the latter are repeat flowering and thus very good value for money.
4 colourful, water-wise flowers to plant now
Osteospermum ‘Ostica’ and ‘Osticade’ series Commonly known as: African or Cape daisy Colours: Pink, bronze, purple, yellow and white Flowering time: Autumn and spring Position: Sunny, great for pots and borders Temperature: Frost hardy Height: 45cm
Gazania rigens ‘Kiss’ series Commonly known as: Gazania, treasure flower Colours: ‘Yellow Flame’, ‘Orange Flame’, ‘Rose’, ‘Mahogany’, ‘Flame Mix’ Flowering time: Autumn, spring, summer Position: Sunny Temperature: Frost hardy, and heat-loving ground cover Height: 30cm
Lobularia ‘Stream’ series Commonly known as: Alyssum Colours: White, pink, dark pink, lavender, purple Flowering time: Autumn, spring, summer Position: Sunny to semi-shade – magnificent in pots! Temperature: Frost hardy Height: 25cm and spreading
Dianthus x barbatus ‘Diabunda’ Commonly known as: Sweet William Colours: Purple picotee, red picotee, mixed Flowering time: Autumn, spring, summer Position: Sunny, perfect for borders Temperature: Frost hardy and heat loving Height: 30cm
Fool Jack Frost
It’s a good idea to grow your winter edibles in pots that can be moved to a sheltered, sunny spot. Leafy veggies like spinach, Swiss chard, salads and Asian greens, as well as peas, will all grow well in containers. Frost normally does no damage to root vegetables, but if you have heavy soil you might have more success if you grow crops like beetroot and baby carrots in containers too.
Ornamental kale = smart winter colour
Ornamental kale is not regarded as an edible plant (it is very bitter) but it is a stunning annual with which to fill your winter garden. The foliage colours in the centres of the frilly rosettes will become more intense the colder it gets. Plant lots!
How to identify the toughest of the tough for fighting frost
- Deciduous plants go into a rest phase in winter. They shed their leaves, harden and thicken their cell walls (so there is less moisture in branches and stems to freeze), and then simply wait for warmer soil and air temperatures to sprout new growth again.
- Hardy evergreen plants with needle-like or tough, leathery leaves, scales, hairs or protective growths on soft stems will easily survive cold winters. Some also have the ability to increase their sugar levels so that plant cells will only start freezing at very low temperatures.
- Winter sleepers – Perennial plants that die down above the soil after autumn and remain completely dormant in winter are always a good choice. They will only start growing again when it becomes warmer and safer outside.
- Plants that are indigenous to a region will always be the best option, as they have the ability to adapt to the climatic conditions of their natural habitat.
- Screening – Use small trees and large shrubs as screens to protect other more tender plants from cold winds. You should remember, however, that frost can still occur close to dense hedges and walls as cold air can build up against them.
- Get to know the frosty parts of your garden. Rather use hard landscaping elements there, like paving, gravel and garden art.
Top tip When wondering what to plant, an old gardening tip is to find out which plants grow well in your region, and to plant lots of them. In difficult climates you should be a ‘thief’ with your eyes to see what grows well in neighbouring gardens before planting up your own.
Did you know?
Winter veggies need at least 6 – 8 weeks of good growth before major frost. If you are unsure when to stop
sowing, work back from your first frost date and see when the cutoff should be. This general guide, drawn from the University of the Free State’s website, indicates the likely date when 50% of each region could experience frost:
- Limpopo: 19 June
- Mpumalanga highveld: 29 May
- North West: 26 May
- Northern Cape: 26 May
- Gauteng: 24 May
- Free State: 16 May
- KwaZulu-Natal (subtropics):2 June
- Eastern Cape: 26 May
- Western Cape: 9 June