It was subsequently featured in a Reuters report on high-rise gardening in Asia.

The garden - located in an HDB maisonette - was notable for the lush foliage that rose overhead and continued up the two-storey-high balcony space.

Now, even though you may not have the luxury of such a space for your plants, the fact remains that height is often the most overlooked or forgotten aspect of garden design.

I was reminded of this during a conversation with veteran British garden designer Julian Dowle. Dowle, who has won a record 11 gold medals at the prestigious Chelsea Flower Show, was in town last year to take part in the inaugural Singapore Garden Festival.

He noted that because of the way many people draw up garden plans - that is two-dimensionally or viewed from the top - the designs tend to be, well, flat.

Making use of the vertical aspect - or the third dimension - not only gives you more room for gardening, but also gives the space a sense of fullness. This is especially so if the planting can be layered or arranged in 'tiers'.

A common mistake is to rely on store-bought plant stands or racks or just raise some pots on upturned ones. That's because this only succeeds in raising the planting to hip-height at most (and because that's also the height most commercial stands go up to).

Instead, aim for a variety of heights among your plants and planting - for example some knee-high, others waist- or chest-high and even overhead if possible.

For those with limited space (or if you also use your balcony for, say, drying the laundry), walls offer the best way to create an impressive garden on a very small footprint.

Now, you could simply attach containers to the wall using a drill and screws. But that's a lot of drilling and holes in the wall, if you've got a lot of containers, and their positions tend to be relatively fixed.

A more flexible alternative is to use a strong trellis such as a wire or metal frame or grille mounted on the wall. This frame then acts as a 'canvas' for you to hang or secure wall containers in different arrangements and to re-arrange them quickly and easily as your garden or collection grows.

Depending on how you arrange the containers, excess water or the overflow can be drained from the upper pots into those lower down which means you do not have to reload the watering-can so often.

The frame also allows you to secure taller plants or those with soft, thin stems and keeps them from being blown or knocked over.

On my balcony, a combination of a frame arrangement and tall plants (a dracaena and a schefflera) were used to maximise space as well as screen out an ugly air-con compressor.

To ease the weight load on the frame, use plastic containers and a lightweight potting medium (such as expanded clay aggregate) where possible.

For small gardens or balconies, more pots of fewer varieties of plants will tend to look better than a rojak of many different types of plants.

The same applies to your choice of containers - keeping to the same colour, or within the same colour palette, will create a neater appearance.

And remember, it's not just plants you can hang on the frame. Add interest to the arrangement with ornamental plaques, plates, garden lighting and even wall-mounted water features.

With enough space and imagination, you might even want to attempt something as ambitious as the Botanic Gardens' two-storey green wall or French botanist-garden designer Patrick Blanc's six-storey one on the facing page.

The sky, make that the ceiling, is your limit.

This column on gardening appears on the last Saturday of each month.

Send your pictures to stlife@sph.com.sg