Garden Guru: Following the scent

Skimmia japonica Reevesiana shows off. Photo / Supplied

Far from being downtime, winter in the New Zealand garden should be, if not a turbocharged riot of colour, then at least a reliable splutter of interest. And even though it's been a harsh one this year it is amazing how resilient some of our plants can be.

Those who like the subtropical deal may well be feeling a bit bruised and battered with aloes and bromeliads - even coastal natives such as puka - melted to slush in exposed places.

But if you prefer a more Northern Hemisphere palette of plants, your patch will probably have surfed through the cold unruffled.

Some of the most delicate flowers prove to be the toughest and seem to thrive on the cold - my drifts of hellebores hang their heads more than ever after a frost but soon spring back as the morning sun breaks through. And what is great about so many winter-flowering shrubs is the scent they offer up as well as a much needed shot of colour.

Everybody loves a daphne. Quiet and deepest green, they sit tidily minding their own business for much of the year, giving much needed substance to floppy flower borders. But now is their chance to shine. In fact it's impossible to pass one without noticing the sweet fragrance carried on a breeze.

Most people go for Daphne odora. The form leucanthe is said to be the most reliable, but the white form alba has just as much scent and looks great in combination with golden-leaved natives such as Corokia Sunsplash and gold libertias.

For hiding a fence or planting down a shady side passage, Daphne bholua is the best choice because it slowly suckers about, grows relatively quickly, and reaches head height.

This year specimens might have lost most of their leaves but you should still get the wonderful scent. All daphnes enjoy a dose of Epsom salts once a year and a bit of light shade through the day to prevent the leaves yellowing. If you want to get the best out of them in a vase, pick only short sprigs and immerse them up to their necks in the water.

Three large shrubs which don't dazzle quite so much with their flowers but still offer buckets of allure with their spicy fragrance are the cornelian cherry (not a cherry at all), a winter honeysuckle that looks like no honeysuckle you could imagine and wintersweet (Chimonanthus praecox).

These all need quite a bit of space and don't provide the most exciting of leaves in summer but if you have the room and can get a summer climber to play in the branches, they make intriguing background plants which will shine now.

Cornus mas, the so-called Cornelian cherry, clothes its bare branches with masses of tiny gold flowers. The effect is brief but striking.

The blooms of chimonanthus are curious affairs. Flesh-coloured and translucent, they appear on the bare branches like tiny starfish. This is a shrub that takes a few years to get established before it will perform.

Winter honeysuckle is much quicker. I find the flowers a bit tatty and the bush a bit of a haystack but their scent helps you overlook all that. Lonicera x purpusii is by far the better form to own if you can get it, rather than the usual Lonicera fragrantissima which can never decide whether to keep its clothes on or off in cold weather.

Many viburnums come out to play at this time of year. Viburnum tinus is a good evergreen workhorse with flat heads of light-scented flowers. It can be a martyr to thrips in summer though so keep it well watered.

Viburnum x bodnantense makes a classic tall vase spattered rather meagrely in heavy scented blooms but for smaller gardens Viburnum carlesii and Viburnum x burkwoodii offer better scale - big fat heads of flower and knockout scent.

Sarcococcas are often overlooked as useful small evergreens for shady places. Some clip reasonably as a box-like hedge but Sarcococca hookeriana digyna is the one to watch out for - it has willowy grace and a turbocharged scent you will catch at 20 paces.

Warmer weather brings out the best fragrance from many flowers but the witchhazels (hamamelis) will give their best in sub-arctic conditions.

Hamamelis have a reputation for sulking in warm humid areas but the hybrid Jelena is said to be easier than most. They enjoy an acidic soil which isn't too heavy or wet and dappled shade too, but the one thing to get right is to water them copiously through summer.

Hamamelis are best left unpruned to develop their graceful outstretched arms. They can look a bit drab and pedestrian in summer - but then who looks a million dollars 24/7?

Could do this week

* Watch out for slugs and snails which will be feasting on the bonanza of new growth. Vulnerable plants such as hostas, arthropodiums and emerging delphiniums can be surrounded with copper strips, eggshells or wood ash to deter these pests.

* Blue-up hydrangeas by adding aluminium sulphate or make them blush pink by adding lime around the drip-line of each bush. Both processes may take several years repeating the treatment before you see any tangible results and in the end you may decide you preferred the muddy in-between.

* Aloes are a welcome winter warmer but after flowering clean off the deadheads with a sharp set of secateurs.

* Plant begonia and gladioli tubers in a potting compost indoors. For begonias be extra careful to water the compost before inserting the corm at the top so water doesn't sit in the dimple.