The culture of winter gardening evolved in Europe, a response to their long, gloomy winters. By contrast, Australian winters are briefer, sunnier and filled with interest – if you know what to do. What is a European winter garden? What can an Australian gardener in a temperate zone do to keep their garden filled with interest? What can food growers grow during the coldest season?
Introducing the winter garden
European winter gardens developed from the 17th century onwards, their evolution was made possible by advances in glasshouse design and construction, becoming larger, more complex and better suited to horticulture than the orangeries that preceded them. Winter gardens provided a warm, leafy, flower-filled escape from the unending damp and leafless gloom of a northern winter.
Being raised by a family of gardeners in London, I took it for granted that you made an effort to create microclimates so you could grow rare and exotic plants better. Family and friends competed with each other and in gardening societies to have the earliest and best blooms.
My first full time job included maintaining the Avery Hill Winter Gardens in London some forty years ago. Unique in south east London and set on a landscaped rise in Avery Hill Park, Avery Hill Winter Gardens had both indoor and outdoor attractions.
The showpiece is the glazed conservatory complex which includes three expansive and interconnected glasshouses: a tropical house, a heated temperate house and a cool house heated so as to just exclude frost. Frost protection greatly extends the range of plants that can be grown in a frost-prone climate.
England’s occasional harsh winters and late frosts can significantly damage a range of beautiful plants, like sasanqua and japonica camellias, or colourful hebes, New Zealand flax and cordylines. Trained against the red brick walls adjacent to tree ferns, camellias and arum lilies grew luxuriantly in Avery Hill’s cool house.
The temperate house is tall enough to accommodate a mature Canary Island date palm which grew commandingly in a central circular raised bed. A large collection of succulents and cacti, and tender, montane plants from the Mediterranean, Central and South America, Australasia and South Africa also grow there. Four raised beds accommodated four geographical plantings.
There was also a good collection of heritage garden tools used to maintain the winter gardens and some of them, like the large water barrow, were still used by us.
The stove house was famous in south east London. In summer, sweet frangipani scented the humid air and, on occasion, it offered visitors a chance to taste home grown pineapple and sugarcane. Just a mention on the radio that the bananas were ready to eat and there would be a queue waiting to sample a London grown fruit.
In winter, you could sit inside and read a book and, while your toes defrosted, you could watch nesting sparrows and blackbirds hunting amongst the vegetation for insects to feed their young. In the warmth, they hatched and fledged earlier than outdoors.
The glasshouse complex was surrounded by formal gardens sheltered by high red brick walls designed to trap the sun’s warmth and permit the cultivation of heat-loving plants from New Zealand, the Mediterranean, California, South Africa and Australia.
Typical of a European winter garden, containerised specimens of citrus, cycads and palms were kept inside during winter and placed outdoors in the surrounding walled garden during summer.
Persian iris , Turkish tulips and star of Bethlehem (Ornithogalum umbellatum) benefited too, as did alpine plants. Alpines in a winter garden may sound curious, however while they grow at high altitudes above the tree line, they need a protective blanket of snow which acts as insulation from harsh frosts that could otherwise freeze the ground solid.
Brilliant blue ceanothus from California, and shaggy, shrubby Mediterranean euphorbias, New Zealand leptospermum and olearia – always vulnerable to a severe English winter – thrived at Avery Hill and in the sheltered, warmth-trapping microclimate, they bloomed precociously and earlier there than elsewhere in London.
You can glimpse Avery Hill Winter Gardens here (maybe turn off the sound), but it isn’t as diversely planted or as well maintained as it was when I worked there.
What to do in your garden this winter
Celebrate winter by sowing cold-loving crops: nasturtium, watercress and chervil make steady progress and robust growth. As the dry season begins in eastern and northern Australia, regularly check seedlings, transplants and potted plants are kept adequately moist during drying, sunny, windy weather.
Now is the ideal time to plant asparagus, artichoke, cardoon (except WA, where it is a scheduled weed) and Jerusalem artichoke plants, onion sets and onion and leek seedlings. All they need is the basics: compost rich, well dug, freely draining, pH adjusted soil.
Buy a pH test kit from a garden centre to determine if your soil is acidic, alkaline or just right. Remember that all members of the onion family – aka alliums – prefer soil that is slightly alkaline, around pH 7 (neutral) to pH 7.5 (alkaline). If your soil is more acidic than this, apply dolomite at a rate of half a handful per square metre, rake it in to the surface and then water it in. Wait two weeks for it to alter the pH before adding any other soil improvers, like gypsum (to break up stiff clay) or composted manures. After that you can sow or plant.
Onions grow healthily in soils which are relatively low in nitrogen, so don’t feed them with poultry manure or nitrogen-rich fertiliser. Check the back of the pack for information on contents. Home made compost, well composted cow or horse manure suits them well. Sprinkle a handful of mineral rock dust, a gentle, slow release fertiliser, per square metre and rake that in before planting.
Lightly trim lemon bushes to shape. Once you’ve finished harvesting their fruit, lift the crown on established bushes so the lowest leaves are no less than half a metre above the soil level. This helps avoid diseases present in the soil being splashed into the foliage and causing disease. Remove suckers sprouting from below the graft point.
Once deciduous trees are leafless, take the opportunity to prune off any weak, dead, diseased or rubbing branches.
Do you shred your own prunings for mulching? Do not reuse them under the same plants as they may harbour pests and diseases which may spread in spring to cause more trouble.
Use dead foliage for insulation. In London I had a collection of around 140 ferns, some of which were cold-hardy and some of which were cold-sensitive. I gathered the dead fronds from my hardy ferns, like male fern, and used them as insulation to protect the crowns of cold-sensitive ferns and other delicate herbaceous perennials, like Incarvillea. No dead fern foliage? Use hessian or straw.
I protected alpines and tender evergreen ferns, like Asplenium bulbiferum, by placing bricks around each plant, surrounding them with chopped dead fern fronds, and placing a pane of glass over the top. My in situ alternative to a garden frame was highly effective, if not as grand as the winter garden in Geneva illustrated above.
Plant garlic. If you haven’t already done this, June is a good time to start growing garlic from cloves. Avoid using imported garlic, since this is routinely bleached to look appealingly white. Bulbs are also chemically treated to prevent sprouting in storage, both of which impair propagation and growth.
* Don’t let vermin eat your veg! Open stored vegetables, like pumpkin, apple and sweetcorn attract rats into kitchens and garages. Apart from using rat and mouse snap traps, storing produce like tomato, eggplant, carrot, pumpkin and sweetpotato in an old-fashioned meat safes is one way I have safeguarded my harvest.
* Protect freshly sown seed of peas and beans from vermin. Dust them in powdered sulphur before sowing. My grandfather harvested prickly stems of dead gorse (not for Australia) and cut them into long sections. After sowing peas and beans in a furrow, he covered them with a single section of gorse before backfilling with soil. Burrowing vermin would catch themselves on the spines. He had more success than I did, so in the end I started growing my own gorse at home.
* Do you economise by reusing old propagating mix? Then be sure to pasteurise it before reuse. Pour boiling through it to kill any pathogens, like damping off disease. Allow mix to cool and dry before sowing.
Winter is the best time for planting cool climate herbs. Grow larger growing herbs, like bay and lavender in tubs, and underplant them with low-growing groundcovers like mint and thyme. Smaller growing herbs, like balm, parsley, dwarf rosemary, sage and winter savoury often succeed best in smaller containers, shallow bowls or vegetable packing boxes. Use fresh, clean potting mix when planting.
Help lemon bushes to rest between June and July. Reduce the frequency and volume of water applied, but do water in an application of iron chelates and trace elements.
Control overwintering pests and diseases. When deciduous fruit trees, like peach and persimmon and vines, like grape, are fully leafless, spray stems, trunks and bark fissures with lime sulphur. If the tree overhangs vegetation or lawns, cover them with a sheet to absorb any droplets of runoff. Lime sulphur burns foliage and splashes should be washed off immediately.
Do you recycle fallen fruit tree leaves and spoiled fruit? Use the leaves as mulch, but make sure to use them elsewhere. Bury spoiled fruit 45cm deep in the ground. This contains pests and diseases and prevents vermin from benefiting.
Store fresh apple, pear and quince over winter. Pick carefully, wipe clean and when skins are throughly dry, wrap each fruit individually in a single sheet of newspaper. Store in wooden packing boxes lined with a few sheets of newspaper and place in a cool, dry, well ventilated space, such as a garage. Use bruised fruit, which spread rot, immediately for bottling or preserves.
Reduce the frequency of feeding and the potency of fertiliser used. Feed vegetables once monthly, except salad vegetables which should be fed once every three weeks. Use ordinary seaweed fertiliser (not one that has been fortified with nitrogen) or a ‘flower and fruit’ fertiliser which will have less nitrogen and more potassium. Watering and feeding in the morning is essential and this reduces the risk of mildew and rust diseases developing.
Must do this month
Be ready for frost and hail. Keep a supply of hail protection mesh, shadecloth, old net curtains or old blankets handy for draping over tender crops before adverse weather, removing once it has passed.
Prevent ice splitting water features and water butts. Float a few tennis balls in them.
Keep paths and steps safe. Regularly sweep paths and steps of fallen fruit, leaves and flowers, camellias can be especially slippery. Control slime (algae) growing on paths and fences by spraying with one part white vinegar to three parts water. Repeat three weekly in persistently calm, damp conditions.
Give your lawn a winter service. Winter grass, moss and other lawn weeds thrive in hungry, acidic, scalped lawns. Give them a hard time: raise the height of cut as high as your mower permits. Apply one handful of dolomite per square metre and water this in. Two weeks later, apply one handful of blood and bone per square metre.
Get even with bulbous weeds. Bulbous weeds, like onion weed and oxalis, thrive in regularly cultivated soil where disturbance, especially attempts to dig them out, more often increases their numbers and aids their spread.
Carefully expose their base, removing mulches and assess their depth by eye. Trim off leaves if they obscure your view.
Gently pour boiling water into and around the base, aiming to envelope the whole bulb in scalding water. Because this takes practice, more than one application may be required at first.
How do I maintain colour and interest in my garden in winter? This was a question I was asked by a listener on gardening talkback on ABC Radio New England. There’s more than time permitted, so here is my illustrated reply:
Last word: antipode
Apart from meaning a location on the opposite side of the world, antipode also means a direct or diametrical opposite. Northern European winters are long and gloomy, so it’s unsurprising that the culture of winter gardening evolved to lift the spirits.
Every year the gardening media in Melbourne seek cheery stories to help Melbournians survive their ever so tepid winter experience. Also expect that seasonal repetition of magazine winter stories which oversimplify the season in Australia and the opportunities it presents keen gardeners.
The Australian winter doesn’t fit the neat three month period allocated it by English settler culture. Not only does one size not fit all, Australia is a global hotspot for biodiversity. Australia’s cool seasons are extraordinarily rich in flowering plants. This continent contains almost every single climate zone imaginable and each region has a multitude of microclimates. Good gardeners also learn how to exploit the microclimates in their own plots.
Looking for inspiration in winter? Ditch that tired old gardening magazine. You don’t even need a garden or to spend much money, just take a stroll in the Australian bushland or your nearest botanical garden. Even a walk around the block will lift your spirits.
How do I maintain colour and interest in my garden in winter? Take it from this seasoned winter gardener – Australia lacks neither colour nor life in winter. It may not be conveniently assembled in one winter garden, but it’s definitely there and hiding in full view.
Jerry Coleby-Williams RHS, Dip. Hort. (Kew)
31st may 2020