Root awakening

“New Guinea Fan” (above).
“New Guinea Fan” (above).PHOTO: WILSON WONG
It has lantern-like pods or fruit with a thin covering (above).
It has lantern-like pods or fruit with a thin covering (above).PHOTO: SUSANNE PHUA
The seeds, which have a white heart-shaped print (above).
The seeds, which have a white heart-shaped print (above). PHOTO: SUSANNE PHUA
Well-draining soil needed for healthy roots.
Well-draining soil needed for healthy roots.PHOTO: LEE ZHI HAN
Fine residue maybe from fertiliser.
Fine residue maybe from fertiliser.PHOTO: KAREN CHIA

Grow cactus in a mix with coarse materials

What is this plant and how should I care for it? My friend said it should be potted with only stone and sand. How do I reproduce it as it has no flowers?

Alfred Chua

It is a cactus. It is likely a species of Cereus and, probably, Cereus tetragonus "Fairy Castle".

To grow this plant well in Singapore, you may want to grow it in a porous, well-draining growing mix, consisting of coarse materials such as pumice and burnt earth.

The proportion and the type of material will depend on your growing conditions.

The plant should be grown in a sunny spot and the root zone should be allowed to dry out a little between each watering.

Do not allow the root zone of the plant to dry out completely as it will be detrimental to the plant's growth.

You can propagate it using stem-cuttings by cutting the top part of the cactus.

Allow the cut end to dry and heal before putting it into a new pot of growing medium to root. During the rooting period, put the cutting under semi-shade and the growing medium should be kept just moist and not soggy.

Balloon Plant's fruit can be used in crafts

My children and I found a beautiful vine growing in our garden. It has lantern-like pods or fruit with a thin covering. They were green when young, but turned brown as they aged. The seeds, which have a white heart-shaped print on them, are green at the start, but turn black when they mature. What is this plant?

Susanne Phua

It is commonly called Balloon Plant or Love In A Puff. Its botanical name is Cardiospermum halicacabum.

The fruits are very interesting as they look like little balloons and the seeds have a heart-shaped marking. They can be used in craftwork, such as eyes for figurines.

This plant is grown here more as a medicinal plant and can be found in some neighbourhood community gardens. It is used to treat ailments such as various digestive disorders, rheumatism and snakebites.

Well-draining soil needed for healthy roots

I planted a tomato plant in January. It bore flowers, but not fruit. Also, some leaves periodically display brown or white patches and wilt, while some roots remain exposed even after soil replenishment. What should I do?

Lee Zhi Han

In Singapore, only small fruited tomato plants are rewarding to grow as they tend to be more heat-tolerant.

Larger fruited ones tend to have problems producing fruit under local conditions and are more prone to various diseases that cause plants to die prematurely.

The presence of white patches and brown leaves could mean that your plant is infected by a fungal disease, such as a powdery mildew.

This can be resolved by growing the plant in better ventilation.

Ensure that it gets sufficient and direct light to grow well. You may need to apply chemical contact fungicides such as Captan to manage the disease.

Ensure that the plant is grown in friable and well-draining soil to promote healthy root development. Soil that is low in organic matter tends to be compact and drains poorly. All these can lead to poor growth and an unhealthy root system.

The pH level of the soil may also not be ideal and such a situation will lead to some nutrients being locked up or excessive.

When preparing soil to grow your plants, ensure that you incorporate sufficient mature compost into the soil. The resultant moist soil mix should form a ball which breaks apart easily when some pressure is applied.

Periodically, mix organic matter into the soil with a fork, but be careful not to damage the roots.

Also, put a layer of mulch consisting of compost on the soil surface to keep the roots cool and moist in hot weather.

Fine residue may be from fertiliser

I bought a money plant six months ago. The plant was well until two months ago when I noticed the outside surface of the pot has fine, powdery, thread-like remnants. I cleaned them off, but they returned. What are they?

Karen Chia

They may be fertiliser residue which have leached through the semi-porous surface of your glazed flower pot.

This phenomenon can also be observed on plastic pots at the rims and drainage holes at the base. Depending on the plant type, excessive fertiliser salts in the growing medium can burn roots or lead to toxicity.

For now, you may want to reduce the application of fertiliser to the plant and water it thoroughly now and then to flush out excessive fertiliser salts.

In severe cases, you may want to change the soil. However, do so cautiously to reduce damage to the root system of the plant.

Tip: Cordyline "New Guinea Fan" has unusual leaf arrangement

Cordyline or Ti Plant are popular landscape plants that are appreciated for their colourful foliage.

The unusual Cordyline cultivar called "New Guinea Fan" stands out from the crowd and is a one-of-a-kind plant that should be included in every tropical-themed outdoor garden. It will be a conversation piece.

Unlike other Cordyline, where their leaves are arranged spirally around the stem, this cultivar has leaves that are arranged roughly as two ranks along the stem, creating a unique fan shape. It has long, narrow dark-olive green leaves which are held on pink petioles.

It can be grown like other Cordyline and grows easily from stem-cuttings. Do note that it is a tall and large growing cultivar.

•Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore ( He is also an NParks-certified park manager.

•Got a gardening query? E-mail it with clear, high-resolution pictures, if any, and your full name to

A version of this article appeared in the print edition of The Straits Times on October 17, 2015, with the headline 'Root awakening'. Print Edition | Subscribe