Two hours - that is how long Madam Chua Hoon, 76, spends every day on her bonsai plants.

More than 300 of these ornamental, artificially dwarfed trees - including ixoras, junipers, wrightias - sit in pots and trays in her front garden. They also line the side of her corner terrace house in Telok Kurau.

She uses a handheld water spray to mist her beloved plants. Out- of-place branches or leaves are snipped off with a pair of household scissors.

Drawn to their small size and charming designs, Madam Chua, a director in a jam-manufacturing company, has been growing bonsai for the last 42 years. "Some bonsai are so tiny, you can hold them with one hand," she says. "They are so cute, you wouldn't think they are actually trees."

Next month, the biggest bonsai event here - the Penjing & Artistic Stone Exhibition & Competition - will take place at Gardens by the Bay as part of this year's Singapore Garden Festival.

This is the 12th edition of the competition, which started in 1994 and is held once every two years. It will feature 80 units of bonsai in four categories - small, medium, large and group.

Small bonsai have a width and height of under 30cm; those classified as medium have dimensions of 30 to 70cm; while large bonsai have dimensions of 70 to 100cm.

A panel of three bonsai experts will judge the entries based on their rootage, branching, leaves and overall beauty, among other criteria.

Three awards will be given out in each category: Gold winners will receive $300, silver winners $200 and bronze winners $100, in cash. One grand winner will also receive an additional $100 in cash. Registration is closed.

Besides bonsai, there will also be an exhibition of 40 units of artistic stones, landscaping on tray and antique bonsai pots.

The event is organised by the Singapore Penjing & Stone Appreciation Society, the only registered society here dedicated to the care and appreciation of penjing and stone. It has more than 500 members, aged 30 to 86. Most of them are more than 50 years old.

Madam Chua, the society's president, says: "We want to encourage more people to take note of bonsai and discover how beautiful and delicate this art form is."

One participant is commodities trader Hoon Woei Sheng, 52, who will submit at least two wrightias, each 20 years old.

"I have taken care of these plants for three years and am very pleased with the final shape they have grown into.

"Winning is secondary. I am just happy for my plants to be displayed."

He has about 40 bonsai in his terrace house in Farrer Park.

Another participant, Mr Kelvin Kweck, 52, will submit at least one bonsai - a 15-year-old wrightia - for the competition.

The owner of a mechanical and electrical engineering company, who has 12 bonsai outside his five- room HDB flat in Bukit Panjang, says: "Each bonsai tells a unique story through its shape and markings. It is fascinating to imagine the story behind every single bonsai."

Although the term "bonsai" is Japanese, the art form is widely believed to have originated from China under the name "penjing", meaning "tray scenery".

The practice spread to Japan - reportedly in the eighth century - where it was called "bonsai", which means "plantings in a pot".

Experts say that while bonsai generally refer to a single tree, penjing can refer to a scene incorporating stones, figurines or more than a tree.

Several plant species - such as wrightias, junipers and Chinese elms - can be cultivated as bonsai.

They are available from nurseries such as Chengtai Nursery in Sungei Tengah and Bonsai Gallery, off Sembawang Road.

Chengtai Nursery sells bonsai plants imported mainly from Indonesia, Malaysia and China. Depending on the plant's species, size, age and design, a single plant can cost from $15 to more than $3,000.

For all of bonsai's charm and beauty, sellers and experts note they are not popular among the young.

Chengtai Nursery's retail manager Philip Tan, 38, says most of his customers are in their 40s or 50s. "It is rare to find young people liking bonsai. Most don't have the time to sculpt the plants into the desired shape which can take years."

However, he notes there is a slight increase in the number of younger enthusiasts in recent years. "They tend to get to know about bonsai through the Internet and social media and find the plants cute."