ROSELLE MAY BE SUNBURNT; WHITE LAYER ON KAILAN IS A PROTECTIVE WAX SURFACE
Brown patches appeared suddenly on my roselle plant and, two days after I took the photograph, its bud looked to be withering. What is wrong with the plant? It was growing well until the brown patches appeared. Also, there seemed to be a waxy layer on the leaves of my kailan. When I rubbed the leaves, the darker green tone appeared. Is that normal?
From the patches on the leaves of your roselle, it appears that the plant may be suffering from sunburn. Was it grown under shadier conditions or was it transplanted and placed right away under the sun?
Although it is a plant that prefers direct sunlight, the roselle, if grown under shadier conditions for a prolonged period, needs to be gradually acclimatised to more intense sunlight.
A plant that has been transplanted has to produce roots to be able to absorb moisture that it needs under sunnier conditions. It is often recommended to put a recently transplanted plant under cooler and slightly shadier conditions for this process to take place.
Another possibility is that a garden chemical had been sprayed on the leaves that caused the burn.
Never spray oil-based pesticides during the hotter part of the day. It is best to test the pesticide on a small part of the plant before spraying the entire plant with it - this ensures the plant does not react adversely to the chemical.
As for the whitish surface on the leaves of the kailan, that is the protective wax that can be seen on certain cultivars of this leafy vegetable. Plants grown under sunnier conditions will have a more obvious layer of wax. It is normal and the vegetable is safe for consumption.
CHILLI PLANT MAY HAVE BEEN DAMAGED BY RAIN
Half of my chilli plant, which is grown outside my window, seems to have dried out in the middle. Why is this happening?
Is your chilli plant exposed to heavy rain since it is grown outside your window? In general, chilli plants do not take kindly to rain as it can damage leaves, causing them to drop. The excessive moisture can drown the roots and lead to disease too.
It is recommended to grow the chilli plant under shelter in a location where it is still able to get at least six hours of filtered or direct sunlight.
KEEP FRUIT OF WATER JASMINE TO HARVEST SEEDS
I noticed a pair of pods growing on my "shui mei". What are they and should I cut them off, as the normally resilient plant seems to be wilting?
Tan Chay Hoon
The plant is the Water Jasmine (Wrightia religiosa), which is often used as a bonsai candidate as well as grown for its scented flowers.
What you see on the plant is its pair of fruit. You may want to wrap the fruit in a drawstring organza gauze bag so that the seeds can be collected when the fruit ripen and split open. You can grow the seeds or give them to friends.
As for the yellowing, wilting and falling leaves, it may be a symptom of a lack of water.
Ensure your plant is well watered during hot and dry days.
TRAVELLER'S PALM MAY BE LACKING NUTRIENTS
Is the yellowing of the leaves and stems of my plant due to root damage, overwatering, lack of nutrients, fungus or something else? How can I rectify this?
Although called the Traveller's palm (Ravenala madagascariensis), the plant is not a true palm. It is more closely related to heliconias, bananas and cannas.
The yellowing of the old leaves could be due to a lack of nutrients and moisture because of the very small root space offered by the current pot.
You may want to move the plant into the ground or a much larger container. Note that the first option will lead to a plant that will, in time, grow much bigger and taller. Ensure that the plant is watered at least daily and fertilised regularly.
FIDDLE FIG NEEDS TIME TO RECOVER
I recently repotted this plant because it was waterlogged. I put in dry porous soil and one stem seems to have recovered and is sprouting new leaves. The other two still have drooping leaves. How can I help restore the plant's health?
What you did with the Fiddle Fig (Ficus lyrata) is correct. Waterlogged conditions would have damaged the roots.
Cutting away the unhealthy roots and then potting the plant in a well-drained media is the right way to help the plant. However, keep the growing media moist as the roots should not be allowed to dry out totally.
During this time, it is best to place the plant in a cool, shaded and protected location where it can get filtered sunlight for it to produce roots before gradually moving it to a sunnier location for optimal growth.
• 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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