Ginger is a species of Curcuma

What plant is this? It looks like turmeric. Are its roots, stems and leaves edible, whether raw or cooked?

Wan Mustaffa

From the features, the plant is a ginger from the genus Curcuma, which the common turmeric belongs to.

The leaves of the plant have a central red stripe and, locally, there are two species – Curcuma xanthorrhiza (Temu Lawak) and Curcuma aeruginosa (Temu Hitam).

You probably need to dig up the plant to take a look and do a comparison.

Temu Lawak has large rhizomes (underground stems) with a deep orange interior. Temu Hitam has smaller rhizomes where the cut portion will take on a bluish tinge when exposed to air. Both ginger rhizomes are used for traditional medicine rather than for cooking.

Money plant may need more light and a larger pot

Why is my family’s indoor money plant turning yellow? Does it have too much water or need more indirect sunlight?

Kesia Lim-Aswira

Is the side of the plant with the yellowing leaves facing away from the light?

Note that in an apartment setting, natural sunlight often comes in one direction. It is essential to rotate your plant regularly to ensure all parts of it get exposed to sunlight. Those that are kept in the dark will die and the first sign of this occurring is likely the yellowing of leaves.

Next, it appears that your plant is growing in a rather small pot. Depending on the growing conditions, it may dry out quickly if the area is warm and windy.

If the plant frequently dries out and wilts, its lower leaves may turn yellow. You may want to move it into a larger pot as the larger soil volume can hold more water for the plant and allow it to grow.

Finally, have you been fertilising your plant? A plant that is starved of nutrients, especially nitrogen, will exhibit yellowing of leaves. Ensure your plant is fed with pelleted or liquid fertilisers purchased from the nursery.

Weed is a Commelina species

These plants sprouted in my garden recently. They are grown from seeds bought from a shop. What are their names? Are they edible or of medicinal value?

Velena Ho

From the features, what you have is probably a species of Commelina, perhaps the Commelina benghalensis, which is commonly known as the Benghal dayflower, tropical spiderwort and Hairy Commelina.

The plant occurs as a weed here sporadically. It is documented to be used both as a medicinal plant as well as a vegetable.

Papaya plant is infested with sap-sucking pests

How do I get rid of insects under the papaya leaves?

Jeremy Wong

Your papaya plant is likely infested with a sap-sucking pest such as soft scales, which can look like mealy bugs.

You may want to use a strong jet of water to wash them off to reduce the number of pests you need to deal with.

The plant can be thoroughly sprayed with summer oil or a diluted castile solution. These work by penetrating the wax coating on the pests and thereby suffocating them. Repeated applications are required to manage the pest populations. 

Umbrella Tree can grow into a shrub or bigger

This leafy plant has been growing in my planter box for a while. It is crowding and shielding sunlight from my spinach growing below. What plant is it and should I repot it in a bigger container?

Sam Tai Choi

The plant is a species of Schefflera, which is commonly called Umbrella Tree. It is generally grown as an ornamental plant for its distinctive foliage.

Depending on the species, some can grow as shrubs while others can grow into a tree, especially if it is planted in the ground outdoors.

You can move the plant into a larger pot to let it grow bigger and prune it to keep it to a manageable size for your garden. The plant prefers direct sunlight for at least half a day and well-drained soils.

• Answers by Dr Wilson Wong, an NParks-certified practising horticulturist, parks manager and ISA-certified arborist. He is the founder of Green Culture Singapore and an adjunct assistant professor (Food Science & Technology) at the National University of Singapore.
• 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. We reserve the right to edit and reject questions.