Root Awakening: Use ant powder to deal with pests on ornamental plant

Yellowing leaves may be a result of dehydration

My outdoor plant is infested with ants. How do I get rid of the ants? Can I use insecticide? I water the plant regularly, but the leaves are turning brown. Is this also the result of an infestation?

Cecilia Wong

In nature, ants play a number of roles, such as aerating soil, but they can be a nuisance. Since your plant is ornamental and not for consumption, you can buy ant powder at nurseries and sprinkle it on the surface of the soil to manage the ant population.

As for the older leaves turning yellow, it may be a case of the plant lacking water. Do not let this plant dry out excessively. Depending on the growing conditions, you may need to water your plant at least once a day if it is in a sunny location.

Also, check if your plant is pot-bound, meaning that its roots have filled the pot. In such a scenario, the plant will dry out quickly and regular watering may not be enough. In such a case, you will need to repot it into a bigger container. 

Edible plants require direct sunlight for healthy growth

I was told this plant is a kaffir lime, but it does not appear to be one, as kaffir lime leaves have a distinctive twinned look. What is it? Also, are my chilli plants suffering from heat or water stress? The leaves do not look healthy.

Oh Choon Yean

From the features of its leaves, your plant could be a standard lime plant.

The kaffir lime has distinctive leaves with two large, connected lobes that make each leaf look like the numeral eight.

Your chilli plant’s distorted leaves indicate a broad mite infestation. These microscopic pests are not visible to the naked eye.

Broad mites attack young, developing plant tissue and will require repeated application of pesticides – such as lime sulphur or abamectin – to manage.

Your plants’ lanky appearance and floppy aerial parts indicate a lack of light. Expose your edible plants to at least four to six hours of direct sunlight daily.

Move Peace Lily to a cooler spot; vine is a weed

My Peace Lily is not flowering even though it has enough sunlight and fertiliser. What is wrong? Also, there is an unknown plant growing in my backyard’s compost area. What is it and is the fruit edible?

Jocelyn Lim

The Peace Lily (Spathiphyllum wallisii) is a shy bloomer in Singapore’s climate, as it prefers slightly cooler conditions. The heat from direct sunlight will likely dry and stress the plant. You may want to move it to a cooler location with filtered sunlight. Also, repot it into a slightly larger container, as this plant will dry out faster if kept in a small pot with limited soil volume.

The climbing plant in the other photo is Mukia maderaspatana. Its common names include Madras Pea Pumpkin and Rough Bryony. It normally occurs as a weed in local landscapes, and is not eaten as a vegetable but has uses in traditional medicine.

Succulent needs to be grown in a sunny spot

I have watered my succulent every two weeks for more than a year, but it recently started shedding its leaves. Why is this happening and what can I do to keep it healthy?

Eileen Chong

Keep your succulent in a sunny location where it can be exposed to at least four to six hours of direct sunlight a day. Its stretched appearance and lack of colour indicate a lack of light.

The older leaves may be drying out due to a lack of water. Do not let your plant dry out totally for too long. Water it thoroughly each time so that water trickles out from drainage holes at the base of the pot, and let the soil dry slightly before watering again.

In Singapore’s hot and humid environment, succulents need to be potted in a gritty growing mix. A growing medium rich in organic matter will retain too much water, which will suffocate the roots and lead to rot.

Make a tip cutting to propagate plants

My Philodendron Birkin was thriving and I was able to propagate two new plants from it. However, it is now growing only vertically and I am not sure how to proceed. Where should I cut it so it can grow new plantlets for me to repot?

Irene Pinto

If you want to propagate your Philodendron via stem cuttings, you will need to cut the tip of the plant. Cut it in such a way that several leaves remain on the plant, so the stump can photosynthesise with the remaining leaves and generate new growth.

You can remove the older leaves from the cut tip, and let the stem cutting take root in water before moving it into a pot of soil. Alternatively, the cutting can be planted directly in the soil, though you will need to place a clear plastic bag over it to help conserve moisture while it takes root.