How does your garden grow?
Hong Kong has a great climate for plants, but knowing the basic rules is essential if you want your garden to thrive, writes Shirley Lau
SUMMER IS AN intoxicating time, with flowers in bloom and trees a vibrant green. That might give the impression it's the best season for plants. But in sub-tropical Hong Kong, where humidity is high and the mercury never touches zero, the right time for most plants is all year round.
More than 1,000 species of plants thrive throughout the seasons in Hong Kong. Some are naturally quicker bloomers than others, but man-made factors also determine how greenery fares: to ensure optimum growth, always take into account the direction your terrace or balcony faces before choosing what to grow.
'Different directions vary slightly in their weather conditions, which will have a bearing on the growth of the plants,' says Kenny Chan Hing-yeung, founder of flower shops Greenfingers in Central and Tsim Sha Tsui. Because Hong Kong is in the subtropics in the northern hemisphere and has fairly long summers, south-facing locations receive more sunshine than those facing the north. 'South-facing terraces are particularly good for sun-loving plants, such as bougainvillea,' says Chan. 'In locations facing north, plants such as lantana are good because they can stand cold weather.'
For west-facing locations, where temperatures rise and the air may become still in the afternoon, Chan recommends the wax plant hoya, which thrives even in stagnant heat and sunlight. For east-facing terraces, he advises orchids, which prefer milder sunshine'.
Chan says that microclimate - the conditions in a small area - is another factor that drives a plant's growth. 'It's particularly important in Hong Kong, where buildings are tall,' he says. 'A terrace surrounded by tall buildings will have poorer ventilation than one overlooking a football field, and the microclimate can be very different. In this case, choose hardy and sturdy plants such as ficus and rosemary.'
When installing colourful flowers and greenery as a group, careful arrangement is needed to avoid poor co-ordination and turning the terrace into a wild jungle. 'Don't cramp too many plants into one small place,' says Box Design's Richy Ng, who's designed dozens of residential projects that feature terraces or balconies. 'Give them space and let them breathe. Among a group of plants, let one or two main players with distinctive features define the look of the terrace - something that has big leaves, for example. The rest of the plants play a supportive role.'
Another way to enhance the aesthetic value of a terrace involves decorating the plants themselves. Chan suggests installing flowerpots with design patterns that tally with the style of a home's interior. 'The appearance of a flowerpot is of paramount importance in beautifying a terrace or balcony,' he says. 'Some contemporary homes have flowerpots with traditional sculpted Chinese dragons. That's rather out of place. There should be a sense of harmony.'
Plants can also be given a lift with bits of bark, which enhance the look and add nutrients. 'They're one of the best things you can put on top of a plant,' says Richard Feldman, plant aficionado and Lan Kwai Fong Association chairman. 'Aesthetically, they're pleasing. They can also provide nutrients over time because they soften and decompose slowly,' says Feldman, whose 2,500sqft terrace accommodates more than 1,000 plants. 'They also help prevent dehydration ... and can eliminate the impact of heavy rain.'
In times of typhoon, Feldman will tie down some of his tall plants to limit damage. 'A typhoon is more a safety issue than a growth issue,' he says.
Given Hong Kong's great climate for gardening, there's not much that will stunt the growth of a plant as long as you follow the basic rules, which include watering every one or two days. 'Because plants thrive in the Hong Kong climate, you have to actually be sadistic to kill them,' Feldman says.
Or ignorant. According to Feldman and Chan, some people put their plants in peril inadvertently. The biggest mistake is putting a drip tray under a plant pot. 'A lot of people think the tray is there to help the plant absorb water,' Feldman says. 'What happens is that the bottom roots will rot in the excessive moisture and the stagnant water. And the water will breed mosquitoes. Trays are the kiss of death. They kill plants.'
Chan identifies another common mistake. 'Many people assume that they should add fertiliser to plants that look weak and unhealthy,' he says. 'But that's a misconception. Weak plants have a low photosynthesis and metabolic rate. Additional minerals from fertilisers will be absorbed mostly by the micro-organisms in the earth and they breed the growth of such organisms, which may eventually strain the plant.'
To give extra nutrients to a plant, consider making your own compost, which can speed up growth and keep the plant healthy. Feldman grows most of his plants in the compost he makes with a compost-making tool he bought for about $300 through the internet. He puts organic scraps of all sorts - orange peel, egg shells, coffee grinds, teabags and even dog hair - into the container, which is about the size of a rubbish bin. 'But don't put in cooked vegetables or the whole thing will stink,' he says. When the waste accumulates to several inches, Feldman tops it with a layer of used compost and leaves everything to decompose. The debris gradually seeps through the numerous plastic layers built inside the composter. In two to three months, the compost is ready to use.
'Plants thrive on this,' Feldman says. 'They grow faster and greener [in compost than in store-bought soil].' A good portion of the nutrients comes from so-called compost tea, the liquid in organic waste that's beneficial for plants. 'The organic scrap leaches all the wonderful juices from the vegetables that will absolutely fortify the soil,' he says. On a small balcony without space for a normal-sized composter, Feldman advises making compost by storing organic waste in a good-sized flowerpot. Cover it with a lid, leave it to decompose for a few months, and the outcome will be just as good.
Compost benefits your wallet as well as the environment. 'You can always buy fresh earth,' Feldman says. 'But why spend the money? A bag of black soil costs about $400 per 25kg.' Making his own compost saves him more than $12,000 per year in store-bought soil. 'But I think it's more about sustainable living. You're putting less in landfills and less organic materials in a garbage bag.'