Jade Plant needs more light and better soil mix
I bought this plant before Chinese New Year and was told it can be grown indoors. But now, it does not seem healthy and the petals drop easily, even though they are still green. What is the cause of this and how can I save the plant?
The plant is commonly known as the Jade Plant. Its botanical name is Crassula ovata.
It can be difficult to grow in Singapore as it prefers a drier environment and cool nights. Some gardeners have had varying levels of success in growing it here in Singapore.
It appears that the plant is not getting sufficient sunlight. It has also been grown in an overly moisture-retentive potting mix that is not suitable for humid Singapore.
The plant grows best in a location where it can be exposed to at least four hours of direct sunlight daily. The mix should be very well-drained, consisting of largely fine volcanic sand, fine expanded clay pellets or pumice.
The composition will vary according to the growing environment. The roots need to dry out quickly as prolonged wetness at the roots and crown can cause the plant to rot.
You can still save this plant: Just cut out the healthy portions and try to root them.
Heliconia rostrata infested with mealy bugs
What are these white sacs, which attract a lot of ants, and how can I get rid of them?
The pests on your Heliconia rostrata are mealy bugs. They suck sap from the plant and also secrete sweet honey dew which attracts ants.
If you have pets and children, you may want to use less harmful pesticides such as neem oil and summer oil to treat the infestation.
However, for persistent cases, you may want to use chemical pesticides, such as cypermethrin.
When applying pesticides, ensure that you cover the plant thoroughly. It is necessary to repeat pesticide applications at least weekly to ensure the infestation is reduced to a manageable level.
Wear protective gear when you use the pesticide and observe the instructions to apply it safely.
Also, keep young children and pets away from sprayed plants immediately after the application.
Plants under attack by spider mites
The leaves on some of my plants have uneven colour. Both the kumquat (photo 1) and desert rose (photo 2) get about six hours of full sunlight and I have been using homemade fruit enzyme fertiliser on them for about 11/2 months. Also, what is the brown spotting on my Sabah snake plant (photo 3)?
Your kumquat and desert rose could be attacked by spider mites.
These tiny sucking pests cause stippled spots on the leaves due to their feeding habit. As they appear as tiny red dots, you can barely see them with the naked eye.
To remove them, you can use a sulphur soap solution made by grating a sulphur soap bar. Make a diluted solution of it to spray on the leaves of the plants.
You may want to use a water sprayer to wash the foliage of your plants daily to remove pests as well as increase the ambient humidity, making it less conducive for spider mites to thrive.
The leaves of the plants have a yellowish cast and the symptoms could point to a lack of nutrients.
The Sabah snake plant also seems to be suffering from a similar issue.
Enzyme fertilisers made by fermenting various fruit peels is not a complete fertiliser for the plants - the nutrient content of such a solution is generally too low and may not provide the entire suite of nutrients plants need to grow well.
You may want to check the pH level of your soil as certain nutrients may get locked up in the wrong soil pH level range. Amend the soil pH level if it is in the inappropriate range.
Also, consider incorporating good-quality, mature compost into the soil if it is too compacted.
Finally, use a complete fertiliser such as a water-soluble one that is sold in local nurseries.
Young leaves of Ku Li Xin eaten
Is this a medical plant? Is it edible?
The plant is botanically known as Eleutherococcus trifoliatus. It is commonly known as Three-leaved Acanthopanax and "Ku Li Xin" in Chinese.
Various parts of the plant are used in traditional Chinese medicine and its young leaves are used as an ingredient in the dish, Hakka lei cha.
It is a prickly plant that thrives under direct sunlight and in well-drained soil that is kept moist at all times. It can be propagated easily from stem-cuttings.
Water Indian Jujube well to encourage fruiting
I bought this plant recently with fruit that look like dates when they dry up. People call them green dates and they taste like pear. What is the name of the plant? How can I prevent the flowers from dropping so that they can fruit?
The plant is commonly known as the Indian Jujube and its botanical name is Ziziphus mauritiana.
The plant is well-known for aborting its fruit easily and this can be prevented by ensuring the plant is well-watered. It should not be allowed to dry out too frequently which can affect fruit production. The plant also needs at least six hours of sunlight to thrive.
If the plant is grown in a small pot and the roots totally fill the soil volume, consider moving it to a larger pot, which will have more soil to hold moisture.
• Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore (www.greenculturesg.com). He is also an NParks-certified park manager.
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