Hibiscus infested with caterpillars

My garden has two yellow hibiscus plants with many flower buds, but they do not bloom and often fall off after a few days. Every morning, there are black, seed-like objects on the floor beside the flower pots, which I thought might be insect droppings. I found these worms under the leaves. What are they and how do I prevent them from infesting my other plants?

Josephine Chan

Your plants have been infested with caterpillars. Remove them using a pair of tweezers and discard them. Avoid touching the bristly hairs on their bodies, as these can cause irritation.

Moving forward, inspect your plants regularly for any pests and act early. In this case, you can spray your plants with Dipel, which specifically targets caterpillars. Thorough coverage is required for adequate control.

The plants may be aborting the flower buds due to dress. Do not let the plants dry out excessively in hot weather. Also, ensure they are not waterlogged or kept in poorly draining soil during the wet season.

Check for thrips in the flower buds, as these pests can damage them and cause them to fall prematurely. Thrips can be difficult to control, but pesticides such as spinosad can be used to treat an infestation.

Banana plant needs potassium

My banana plant’s leaves are green, but look badly torn. Aside from strong wind, what could be causing the damage?

Ivan Ho

There is slight brown and yellow colouration on the lower, older leaves. Banana plants need more potassium than the average plant, so a lack of this nutrient might be causing the issues. You can feed it with a chemical pelleted fertiliser high in potassium. Follow the instructions on the product label.

To make sure your soil is properly aerated, minimise foot traffic around the plant, as this can compact the root zone. Increase the soil’s levels of organic matter by mulching the surface with good-quality mature compost and incorporate this into the rest of the soil. Keep the root zone moist so the plant can absorb nutrients easily.

Remove and pot baby orchids when roots have formed

I have had my orchid for at least four years and it has been blooming regularly. There are new roots at two spots. Should I cut and repot them or leave them as they are?

Joyce Toh

The new roots appear to be those of baby plants, called keikis by orchid growers. Keikis can be detached from the parent plant when they develop roots long enough to be potted separately.

Once you remove them, pot them in charcoal chips. The chips need to be small enough to support baby plants, but not too small to impede aeration and water drainage. You may need to provide a short stake for extra support.

Looking at its shrivelled pseudostems, the parent plant may also need to be watered more often, especially during hot and windy periods.

More time needed for root production in marcotted branch

I wrote to you

in late 2025 about propagating my Bodhi Tree

Chin Lih Shyan

Marcotted branches of woody plants need more than a month to produce roots. You may also want to experiment with a different growing medium, such as peat moss, as sphagnum moss may be too porous and aluminium foil may not be a strong enough seal to stop moisture from evaporating.

Make sure the growing medium is kept moist and not allowed to dry out, and consider wrapping a clear plastic sheet around the branch.

For your Monstera, is the root being submerged in water? If so, the cutting may not be producing roots due to a lack of oxygen in the water.

Consider the “semi-hydroponics” method, where the cutting and the short root sit in moist leca pellets that are not submerged in water.

This process works by way of a water reservoir located several centimetres below the cutting. Water is drawn up by capillary action to moisten the leca layer and the cutting. This will depend on the size of your leca, as larger pellets are not as conducive to this process. Change the water regularly.