Ficus infested with soft scales
There are white spots (above) on the surface and underside of this ficus. What are they and how do I remove them?
Your ficus leaves appear to be infested with soft scales.
If the infestation is not too serious, you can treat it with less toxic pest-control methods: Remove the pests with a soft toothbrush.
For more serious infestations, apply a dilute solution of neem oil or summer oil weekly to kill adult insects and to keep the pest population in check.
As these pesticides work via contact, ensure that you cover all surfaces of the plant when you are spraying the solution.
Repeated applications of pesticide will be needed to reduce the pest population.
Medical benefits of Bitter Leaf need to be better studied
According to the Internet, the leaves of this plant (above) are said to lower cholesterol and high blood pressure and also cure diabetes and prevent cancer. What plant is this? I understand that the Chinese name is nan fei ye.
The shrub is botanically known as Vernonia amygdalina and commonly called South African Leaf or Bitter Leaf. The medicinal uses of the plant are mostly folkloric and the success stories are at best anecdotal. More scientific work needs to be done to substantiate the health benefits, hence one should proceed with caution. Consult doctors before using the plant to treat ailments.
Moth orchid hybrid needs cool environment to trigger flowering
I have a few Phalaenopsis (above). All the leaves are growing healthily. The flower stalks are more than 1.5m long, but they never have flowers. Is it due to a lack of flowering hormones or fertiliser?
The reason for the lack of flowers in many moth orchid hybrids (Phalaenopsis) - which are sold for their showy flowers on long inflorescences for display - may be due to the fact that they require a cool period to trigger flowering.
This is evidenced by observations of local gardeners, who report flower spikes being produced in plants mostly during the year-end period in Singapore, when frequent rains often lead to a drop in the local ambient temperature.
If you like moth orchids and have a shaded location in your home garden, you can perhaps try selections of Phalaenopsis violacea and Phalaenopsis bellina as these are more floriferous under local conditions.
Money plant likely to have mealy bugs
What are these tiny white spots (above) and how do I remove them? Some are found on the leaves and look web-like and mouldy.
Your money plant appears to be infested by mealy bugs, which are a type of sucking insect pests with cottony fluff. You can first use a strong jet of water to wash the insects from your plant.
To treat a serious and repeated infestation, apply a dilute solution of neem oil or summer oil weekly to manage the pests.
Ensure that you cover all surfaces of the plant and the climbing support when you are spraying the pesticide solution. Repeated applications may be needed for long-term control.
Red Flame Ivy a common groundcover plant
I got this plant (above) last year and it started to flower recently. The blooms are small and pink and appear in a string. What is it?
This plant is commonly known as Red Flame Ivy or Metal Leaf and its botanical name is Hemigraphis alternata.
It is a common plant used as a groundcover for landscaping uses. It is also sometimes used in vertical gardens for its trailing effect.
It does well in fertile, moist and well-drained soil, and under semi-shade sunlight conditions, the upperside of the leaves exhibits an attractive silver colour.
• 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.
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