Root Awakening: Avoid over-pruning jambu plant

Plant will remain vegetative without light

I have been growing this jambu plant for about five years, but it has not flowered or fruited. What is wrong?

John Lee

When it comes to fruit trees, it is best to nurture a plant that is raised from a graft or air-layered branch taken from a mature, fruiting tree. This ensures that the plant will flower and fruit reliably. Seed-grown plants can be unpredictable.

Also, ensure your plant is grown in a sunny spot, as the plant will remain vegetative when not given sufficient light.

Give it space to thrive and avoid over-pruning the plant, as it produces flowers seasonally in new growth. Constant drastic pruning will prevent it from flowering, as it will channel its efforts towards producing vegetative growth.

Avoid overwatering, apply fungicide to Cypress

My small pine trees seem to be dying. The leaves are turning brown. Should I water them more or move them to the shade?

Philip Ho

Your plants could be a cultivar of Cupressus, commonly known as Cypress.

The decline could be due to a number of reasons. First, check if you have buried your plant too deeply. The base of the stem should not be topped up with growing media, as it will cause the collar to be wet at all times, leading to disease. Remove excessive soil where needed.

Second, cypresses in general are difficult to grow in Singapore’s wet, humid climate. Consider moving the plant under a clear shelter so it will be shielded from rain but still get enough sunlight. Allow the root zone to dry out between watering sessions.

Third, provide sufficient air circulation. The dense canopy can trap moisture, leading to fungal issues that can kill the foliage. At this stage, you may need to apply fungicides, which are available at local nurseries, to improve the situation.

Stress can cause Alocasia to go dormant or decline

I bought a small Alocasia from the supermarket. After a month, I transplanted it into a 20cm pot, including the repotting soil, rice husks and dried banana peel. I have placed the pot at my balcony, where it gets morning sun. Is there a botanical explanation why the leaves remain evergreen?

Hassan Ali 

You have done a good job keeping your Alocasia alive. Its leaves are green as you seem to have achieved all the optimal conditions for it to thrive.

Alocasia go dormant or decline with stress. Many cultivars are sensitive to a wet root zone and need porous growing media. Overwatering or moisture-retentive soil can cause the corm (underground storage organ) to rot. High-rise growing conditions are also conducive for pest infestations, such as by spider mites.

Orchids are being eaten by caterpillars

My orchid’s flowers have been devoured by small, slug-like creatures that blend with the petals. They have what appear to be black mouths, snouts and claws. What are they and how do I get rid of them?

Lau Wai Leong

Your orchid flowers seem to have been eaten by caterpillars. These pests can be transient – after the current population becomes adults, the problem will resolve itself.

The next flowering may or may not be affected. As such, regular preventive spraying of pesticides may not be necessary, and will be expensive and harmful to you and the environment. If really needed, pesticides such as Dipel and abamectin, which are available for sale at local nurseries, are effective in controlling caterpillars.

Inspect your plants regularly for the presence of pests and act promptly before the damage becomes extensive. Once spotted, a few caterpillars can be removed easily using a pair of pincers, which is cheaper and more environment-friendly than applying pesticides.

Propagate Fiddle-leaf Fig via air-layering

How do I propagate my old plant? A new branch has sprouted after daily drops of diluted fertiliser at the top of the stem. Do I cut it off from the old stem or cut it off together with the old stem? Should I root it in soil or water?

Jocelyn Ng

The Fiddle-leaf Fig (Ficus lyrata) is usually propagated via air-layering, where roots form on a new plant’s stem while it is still attached to the parent plant. You can refer to online videos on how to do so. This plant is not easily grown from stem-cuttings or in water.