Below are my answers to three gardening questions to the second instalment of the Root Awakening column for Mar 2010.
The first question asked about the identity of a tree found growing in the vicinity of the Regent Hotel on Cuscaden Rd, Singapore. That tree is a popular landscaping candidate that is commonly called the ‘Happiness Tree’ and ‘Philippine fortune tree’. It thrives in semi-shade and well draining soil conditions. Botanically known as Garcinia subelliptica, it is a close relative of the common mangosteen and is a slow-growing, medium-sized tree with evergreen, thick and leathery oval leaves. It has one main trunk and adopts a compact and conical crown. Interestingly, it was once planted to form a windbreak in the Okinawa islands, Japan.
The second question asked about a problem – yellowing leaves – encountered during the cultivation of a chilli plant. It is important to ensure that one’s chilli plant is well hydrated at all times. Plants that have suffered severe drought conditions often develop yellowing leaves which are shed subsequently. There may be a need to water your plants more than once daily if it is grown in a windy and sunny location.
One may also want to take the plant out of its pot to check for soil mealy bug infestation as these pests impair a plant’s ability to uptake water. When there is a prevailing infestation, the roots of your plants will have white patches surrounding them. A safe and organic but rather slow method that can be used to treat infested plants is to use diatomaceous earth (available from Known You Seeds (S.E.A.) Distribution). Diatomaceous earth is an inert, non-volatile, powdered substance made from the skeletal remains of diatoms, which have been processed to form razor-sharp particles which cut into the bodies of small insects. Avoid breathing in the dust.
To treat for soil mealy bugs, carefully wash off infested soil from your plants roots and then repot your plant in a soil that has been mixed with diatomaceous earth. Use about 1 tablespoon per one liter of soil. Note that large chilli plants can suffer from transplant shock during the root washing process.
Soil mealy bugs can be difficult to eradicate and badly affected plants should be discarded. Sterilise pots and soil before using them to pot up new plants.
The last question was about mosquito plants. Note that no plant (common ones include Pelargonium citrosum and citronella grass) in existence will repel mosquitoes by sitting in a pot or a corner in a garden. Many plants touted to repel mosquitoes are due to the fact that they have significant amounts of repellent essential oils in their leaves. The repellent effects will only be observable when their leaves are crushed or heated where the essential oils are released into the air.
