When a weed isn't quite a weed

Let's take a second look at the potential of these hardy, unwanted plants
Tan Hui Yee Straits Times 23 Feb 11;

WEEDS have invaded the heart of town.

Tall, billowy blades of grass looking suspiciously like the lowly lallang were recently spotted in the Orchard area, raising questions as to why the Garden City is laying waste to prime land.

The mystery was eventually solved. The 'lallang' was actually an African shrub called Pennisetum x advena 'Rubrum' or purple fountain grass, prized for its foxtail-like flowers and bronze swaying form.

It seemed a simple case of mistaken identity. Singapore's glitziest shopping district was safe from the reaches of the hardy, pervasive lallang, whose dense mounds are deemed a fire hazard.

Yet, the intriguing part is this: The same description applies to fountain grass.

A variant of the species planted in Orchard Link, Pennisetum setaceum (Forssk.) Chiov. or crimson fountain grass, is vilified by the American state of Hawaii as a 'noxious weed'. It is described by the Global Invasive Species Database as 'highly aggressive' in dry, open environments, fuelling forest fires that kill surrounding species, then sprouting readily after a blaze to overwhelm native plants.

Now, Singapore is hardly in danger of fountain grass-fuelled fires, having witnessed unprecedented downpours in recent months. And the variant of fountain grass planted in Orchard Link by *Scape youth park reportedly bears sterile seeds, so it is unlikely to invade other turfs soon.

But the whole kerfuffle over the fountain grass plot has raised larger questions about the role of weed in our cityscape.

Does it make sense to draw such a clear line between weed and ornamental plant in the first place? More importantly, will this attitude work against the Garden City as it races to create easier-to-maintain landscapes so as to cut down on the amount of care its burgeoning urban greenery requires?

One undergraduate interviewed by The Straits Times had this to say of the purple fountain grass: 'It does look like weed, plain and messy.'

But the fact is that weeds come in many forms, some 'messy', some not. There is very little separating a weed from other types of plants, save for personal and sometimes collective opinion, if not prejudice.

Indeed, one country's weed is another's ornament. The Lantana camara, a flowering South American shrub planted in public spaces here, is listed as a 'weed of national significance' in Australia, for it adds fuel to fires and is toxic to farm animals.

The Wedelia trilobata or creeping daisy from Central America is used to green the ground and control erosion here, but has been listed as among the world's worst invaders by the International Union for the Conservation of Nature.

A weed today can also be desirable tomorrow. Biologist Hugh Tan of the National University of Singapore has a simple example. Suppose, he says, you were planting tomatoes in a pot, and the wind happens to deposit the seeds of a wild orchid there. Soon, the seeds grow into rare wild orchids which are more valuable than the tomato.

The tomato's days are then numbered as it is now considered the weed. The moral: 'It's difficult to cast a plant as all black or all white,' says Dr Tan.

Nature abhors the easy categories that Singaporeans are used to. Yet many people here, pampered by the buffet of horticulture offerings on its streets, and even some landscapers who trip over themselves introducing new species from far-flung corners of the globe, overlook the value of readily-available plants in their own backyard.

The lallang, for example, can be used for thatching. It is also used to treat bleeding and urinary disorders in traditional Chinese medicine.

But what is that compared to the thrill of having 226,000 plants from almost every continent grace two giant climate-controlled domes in the upcoming Gardens by the Bay? Or the more than 400 species of local and foreign trees planted by the National Parks Board beside roads and in parks and vacant plots around the island?

With something new and exotic always around the corner, it's easy to view familiar weeds with disdain, or even disgust.

Perhaps this contempt stems, too, from the national obsession with calculable results. Weeds are hard to measure and control. They are nature's survivors, poking out of crevices and flourishing in the shadiest and hardest-to-reach spots without human help. And they are also self-selecting, sprouting profusely where they are least wanted, yet wilting where you want them to thrive.

Their free-spirited character is alien to Singapore's nearly five-decade-old greening movement, which largely adopts a formal 'lollipop and turf' style that places the same trees at equal distance from each other along a road.

The tightly controlled urban greenery has in turn conditioned an entire generation of youngsters to reject messiness and unpredictability - green, purple or otherwise.

This is a pity, because 'messy' plots with a variety of naturally sprouting plants help promote biodiversity in ways a manicured garden cannot. And the city will have increasing use for hardy and fast-growing plants as it seeks foliage that can climb high to envelop rooftops and insulate walls, in a bid to reduce temperatures on a built-up island.

Landscaper Veera Sekaran, who specialises in green walls, says he is cultivating a weed he recently harvested by the road to use in his projects. It does not matter that he has not been able to identify the species so far: It is showing great promise in climbing up concrete.

'A weed is a plant whose potential has not been discovered yet,' he says.

This enlightened attitude may just be what it takes to sustain the Garden City in the years to come, as erratic and sometimes extreme weather makes the hunt for resilient species more urgent.

Given that uncertain future, Singapore can do no better than to embrace ambiguity and whatever messiness comes with it. The answers it is looking for may not come easy. But then again, the answers might just be right under its nose.