Root Awakening: Shui Mei plant infested with aphids

Leaves’ black coating is sooty mould

My big Shui Mei plant developed a sooty black coating on the leaves and now my small Shui Mei (pictured) has it as well. I pruned the affected leaves, but the sooty substance is back. Is it a bug? How can I treat my plant?

Neo Bee Leng

The black substance looks as though it could be sooty mould, a fungus that grows on the sugary excretions of sap-sucking pests. Your plant appears to be infested with aphids, which can be difficult to control. 

First, use a strong jet of water to wash the pests off the leaves. Next, apply a pesticide such as summer oil to suffocate the pests. This can be rotated with other pesticides such as pyrethrins or synthetic pyrethroids like cypermethrin, which can be bought in local nurseries. Rotate pesticides so the pests do not develop a resistance to any of them.

Complete coverage and repeated applications of pesticides are essential for proper pest control.

Plant is likely the long bean

What plant is this? This is not the first time I have seen it in my garden. I removed it previously since I was not sure if it was a weed. If it is not a weed, should I plant it in a pot or in the ground? 

Yap Kat Seng

The young plant seems to be the common edible long bean. You may have planted its seeds in the soil. In future, it may help to label seedlings with their names and the dates on which they were sown. 

Depending on the cultivar, the long bean can grow as a bushy, non-climbing shrub or as a vine. Grow it in the ground with well-draining soil, so it has enough root space for optimal growth.

Butterfly pea plant infested with spider mites

What is wrong with my plant and how can I remedy it? 

Philip Ho

Your butterfly pea plant (botanical name: Clitoria ternatea) has been infested with spider mites, a common pest of this plant species. They are very difficult to control at this stage of severe infestation.

Remove severely infested leaves and wash the plant thoroughly with a strong jet of water. Spray it regularly and thoroughly with summer oil to suffocate the pests. Make it a point to drench the foliage if your plant is in a hot, dry or windy spot. Regular misting can also help to increase ambient humidity and wash pests away.

Diospyros buxifolia is native to Singapore

I spotted this tree near Capitol Building. What is it? Can it be potted and does it grow well in direct afternoon sunlight?

Philip Tan

The tree is botanically known as Diospyros buxifolia. It is native to Singapore and can grow more than 30m tall. It is best grown outdoors in a sunny spot with well-draining soil. Small trees can be temporarily planted in pots, but can be difficult to manage when they outgrow the containers, and when their water and nutrient needs are not met.

Plant is Pucuk Manis

Is my plant the Pucuk Manis?

Richard Low

The plant is indeed the Pucuk Manis, also known as Cekur Manis (botanical name: Sauropus androgynus). It is a leafy vegetable commonly eaten in this part of the world. Cook the leaves thoroughly before consumption.