Brazilian spinach's leaves are edible

What is the name of these plants (above) and are they edible?

Gan Lai Chui

The plants appear to be the Brazilian spinach, botanically known as Alternanthera sissoo.

The young, tender leaves of the plantare eaten either raw or cooked.

It is advisable to cook the leaves, such as by blanching them, if they are to be eaten in larger quantities due to the oxalate found in the plant.

Oxalate crystals, which may interfere with nutrient absorption when eaten, are destroyed during cooking.

Coral Vine grows quickly under optimal conditions

How much water should I give this creeper plant (above)? Is it advisable to grow it in a bigger pot with loose soil and how much sunlight does it need?

Nathaniel Foo

The climbing plant is commonly known as the Honolulu Creeper or Coral Vine. The botanical name is Antigonon leptopus. There is a variety with white flowers.

This plant is best grown under full sun. Given the right sun exposure, it will grow fast and flower often.

As with many climbers, it is best grown in a large pot or in the ground as its growth will be limited by the root size and volume. Ensure that the plant is well-watered during dry weather.

King of Bitters and Indian borage used to treat cough

I was given these plants (both below) from a community garden to treat my cough. What are they? One looks like the mint and the other plant's leaves taste very bitter.

Natalie Simandjaja

The plant (photo 1) is probably the one giving the bitter taste. Its common name is King of Bitters and its botanical name is Andrographis paniculata. It is commonly cultivated as a medicinal plant and used to treat a range of ailments, including cough and sore throat.

The plant (photo 2) is often mistaken to be mint, probably due to its local Chinese name "po ho", which translates to "mint".

It is a plant species of the mint family, Lamiaceae. Its common name is Indian borage and is botanically known as Plectranthus amboinicus. It is sometimes used as a substitute for oregano in dishes and used to treat coughs.

Pot-bound Japanese rose needs larger container

I have had this Japanese rose (above) for about two years. The leaves are starting to yellow or brown around the edges. The base seems "fossilised" too. What should I do?

Angeline Pang Ying Kuang

It appears that your rose is pot-bound and the roots have filled the pot. The medium that the plant is growing in may also be depleted of nutrients.

Also, the chemical properties of the growing medium, such as its pH level, are no longer in the optimal range, so even if nutrients were added, the plant would be unable to absorb them from its roots.

For now, you may want to move the plant to a larger pot where the roots are allowed to grow. The new growing mediumshould be well-draining and moisture-retentive. Do also fertilise the plant to ensure it receives sufficient nutrients to thrive.

Propagate allamanda through stem-cuttings

What is this plant and how do I propagate it? It is getting taller and the stems below have no leaves.

Jeannie Tang Mei Lin

The plant is an allamanda and this is a Cherry Ripe variety which produces long stems that can be trained over a tall support.

Avoid pruning the woody lower segment of the plant as this will not produce new growth and may even cause dieback.

This allamanda can be propagated via stem-cuttings.

• Answers by Dr Wilson Wong, an NParks-certified practising horticulturist and park manager. 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