Happiness Tree stops fires from spreading

I saw this tree in Scotts Road. What is its name and are its fruit edible? The branches have lots of tiny shoots. When the green fruit ripen, they turn orange. The flesh has a texture similar to that of persimmon.

Choo Kock Huang

The tree is botanically known as Garcinia subelliptica. Its common names include Happiness Tree, Philippine Fortune Tree and Fukugi. It is related to the common edible mangosteen, which goes by the botanical name Garcinia mangostana.

This tree is often planted for its decorative foliage and columnar growth form.

In Okinawa, Japan, this tree is planted to protect areas from strong winds. It is also an effective firebreak option. When strategically placed, it can prevent a fire from spreading. Its fruit are not usually consumed.

Marquis de Sade a good indoor plant

What plant is this?

Juliana Tan

The plant is probably Kohleria "Marquis de Sade". Kohleria is a genus that comes under the African violet family, Gesneriaceae. The plant produces colourful flowers and grows well in the tropics. It grows tall and is often shaped like a shrub.

It is a good houseplant for those who live in apartments. It is best grown in an area where it can get at least four hours of filtered sunlight daily. The soil used should be well- drained and moisture-retentive.

Climbers with medicinal properties

What are these two plants? Do they have medicinal properties?

Foong Kin Wai

The plant at the far left is botanically known as Dioscorea bulbifera, commonly known as Air Potato. It is a twining vine that forms bulbils in the leaf axils and tubers beneath the ground. Its tubers can be toxic and must be cooked thoroughly before consumption. The potato is rubbed on skin to treat various issues.

The other plant is the Anredera cordifolia and has common names such as Madeira-vine and Daun Binahong. It is also a climber that produces aerial tubers between its leaf axils. Its leaves and tender stems are eaten as a vegetable.

The plant is said to have anti inflammatory properties.

Counter mildew with sunlight and fresh air

There are white patches on the leaves of my ladies' finger plant. What are they and how do I treat it?

B.C. Niew

Your ladies' finger plant (botanical name Abelmoschus esculentus) has powdery mildew, a fungal infection. You will need to give it as much direct sunlight as possible.

Space out your plants so that they have adequate air circulation. The infected leaves should be cut off.

As a preventive measure, spray chemical fungicides on the leaves. Do let the withholding period elapse before you harvest the fruit. Spraying neem oil, which is an organic pesticide, on the leaves may have a limited effect in severe cases.

Flaming Katy loves the dark

When I bought this plant two years ago, it had big leaves and flowers. However, it has not flowered since. Recently, its leaves turned yellow and were dry. They also fell, leaving only the stems. I trimmed the stems and the leaves grew back, though they are small. What is wrong?

Richard Kho

The plant is botanically known as Kalanchoe blossfeldiana, though it is more commonly called Flaming Katy. It is a short-day plant that requires a long period of darkness. If grown indoors, it prefers to have direct sunlight for four to six hours daily.

The soil should be porous and well drained. Allow the soil to dry out a little before watering it again.

To get the plant to flower, cover it with a box to create total darkness for 14 to 16 hours a day. After four to six weeks of treatment, buds should start to form.

•Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore (www.greenculturesg.com). He is also an NParks-certified park manager.

•Have a gardening query? E-mail it with clear, high-resolution pictures of at least 1MB, if any, and your full name to stlife@sph.com.sg