Grow Red Button Ginger by stem-cuttings

What is this plant and how do I care for it?

Ngoh Lay Yian

The plant's botanical name is Costus

woodsonii. It has common names including Scarlet Spiral Flag and Red Button Ginger. Grow it either under direct sunlight or in semi-shade outdoors.

Its soil should be moist at all times and well-drained. You can propagate this plant with stem-cuttings or by dividing an existing clump.

Invasive Billygoat-weed

I found this unidentified plant growing in one of my flower pots. Is it a weed?

Lin Zi Han

It is botanically known as Ageratum conyzoides and also known as Billygoat-weed, which often sprouts in gardens, lawns and wasteland. It has insecticidal properties.

Plants with medicinal properties

What are these two plants? Are they edible and are they used to treat health ailments?

Felyn Tay

Based on the features that can be seen in the pictures submitted, the first plant looks like Daun Salam. Its botanical name is Syzygium polyanthum.

The leaves of this plant are used in Indonesian cuisine. They also provide relief for itchy skin, while those who have diarrhoea infuse them in water and drink the decoction.

The second plant is an epiphytic fern commonly known as Dragon Scales.

Its botanical name is Pyrrosia piloselloides. Its leaves have been documented as being used to treat skin rashes.

While these plants are known to treat various ailments, it is best not to self-medicate. Consult a certified medical practitioner first.

Ensure pandan shoot has adequate roots before planting in soil

I have tried multiple times to grow pandan in my balcony. Each time, the plant would grow well before its leaves start to turn yellow and dry. All the plants died after a few months. I watered the plants every day and applied fertiliser once a month. What went wrong?

Wendy Lim

Did you get the pandan (its botanical name is Pandanus amaryllifolius) from the market as a shoot tip and plant it in a pot of soil? If that is the case, ensure it has adequate roots before planting it in soil.

Pandan shoots bought from the market usually do not have sufficient roots and their leaves often dry out before new roots are produced.

When you buy a shoot from the market, select one with some roots already present and put it in a small cup of water to allow more roots to form before planting it.

You can use some of the lower leaves for cooking. Removal of leaves can reduce the rate of water loss from the shoot.

As pandan grows near water in the wild, you need to ensure that your domesticated pandan is well- watered. It should never be allowed to dry out.

This plant should not be grown in a windy place as the constant wind will dry it out quickly. It can be grown under direct sunlight or filtered sunlight for at least six hours a day for optimal growth.

Edible, round fruit from Santol tree

My wife and I came across this tree just outside IMM in Jurong East. What is it and can its fruit be eaten?

Yip Kam Seng

It is probably the Santol, which has the botanical name Sandoricum koetjape. It grows into a large tree and produces round, edible fruit that are either sweet or sour. The fruit pulp can be eaten on its own or cooked.

•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