Unknown plants are common weeds with medicinal purposes

My small garden seems to be proliferated with two unknown plants. What are they? Are they of any medicinal value and can they be eaten?

Seh Chwan Lim

The first plant looks like the King of Bitters (Andrographis paniculata). The plant produces extremely bitter-tasting leaves which are reported to have antibiotic, antifungal and antiviral properties. Locally, it is best known for its use to treat sore throats. The plant self-sows via its seeds.

The second plant is the Pepper Elder (Peperomia pellucida). It is a weed that grows frequently in gardens and flower pots. Its leaves are used to treat headaches caused by fever, while the sap from the leaves can be used for abdominal pain and colic. It can be cooked and eaten.

Do not self-medicate. You should check with a certified medical practitioner if you want to use the plants to treat ailments.

Buy seeds from reputable vendors

I bought seeds from an online platform. The resulting plant looks like wild grass. What is the name of the plant and is it edible?

Julia Tham

The plant is the Cupid's Shaving Brush (Emilia sonchifolia), which commonly occurs as a weed locally.

Did you buy the seeds of a weed or have none of the seeds actually germinated? Do buy from a reputable vendor who will sell seeds true to what they should be, as well as those that are viable and have high germination rates.

The leaves of the young plants are reportedly edible. But exercise caution when doing so, as the plant is also reported to contain pyrrolizidine alkaloids, which may cause liver issues.

Hawaii Woodnettle is a common weed

My balcony does not receive direct sunlight at this time of year and the leafy vegetables from the Gardening with Edibles initiative are dying. Despite the lack of direct sunlight, this plant still sprouted and has been growing well. What is it?

Wong Zi Cheng

The plant is probably the Hawaii Woodnettle (Laportea interrupta). It often occurs as a weed in flower pots and flower beds. It is reported to have medicinal properties. The plant is covered with numerous stinging hairs which can irritate skin, so handle it with care.

You may want to install artificial lights to grow edibles indoors where sunlight is lacking. Also, try growing microgreens. These are edible plants that are quick to grow and do not require a lot of sunlight.

Dinner Plate Aralia mostly grown as an ornamental plant

I am told this plant, which I received as a gift, is edible. What is it and how do I care for it?

Denise Low

The plant appears to be the Shield Aralia, which is also known as Dinner Plate Aralia (Polyscias scutellaria). It is a woody foliage plant that is often grown as an ornamental plant for its attractive leaves. It is not commonly eaten locally, although some sources say its young leaves are consumed as a vegetable.

Vine is the Bread Flower plant; Hibiscus must be checked for thrips and water stress

The first plant is grown from a cutting I got from a Malaysian resort. When I stayed there, the air outside my room was constantly filled with the scent of pandan. Resort staff told me it is from the flowers of this plant. I have grown the plant for about two years, but it has not flowered.

Also, my hibiscus plant produces numerous buds constantly, but they drop off before blooming. The plant is healthy. What is wrong with my plants?

Sin Chey Cheng

The vine with flowers that emit a pandan-like scent is the Bread Flower (Vallaris glabra). Its flowers are white and grow in a bunch. The plant needs to be grown in a sunny, well-drained location for it to thrive. It grows as a large vine and a large, sturdy trellis should be erected for it.

There are two possible reasons for bud drop in hibiscus plants. Ensure your plant is well-watered, especially when it is grown in a pot. Do not allow it to dry out excessively until it wilts.

Another reason could be due to a thrip infestation. Thrips are small, rasping insects that can damage flower buds and cause them to drop. They are difficult to spot and treat. Pesticides such as spinosad or fipronil may be used to control them, but they must be rotated with other pesticides to reduce the likelihood of the pest developing resistance to them.

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.

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