Root Awakening

PHOTO: ANTONIO DAROYA

Constant winds, hot sun can dry out ficus plant

I have had this ficus for about two months. Three weeks ago, the leaves turned yellow and black and started falling. A pH meter reading of the soil showed that it was at seven and the sub-soil is highly moist even though I water the plant every other day and add soluble fertiliser every two weeks. The plant gets about four hours of direct sunlight in the afternoon. What is wrong with it?

Antonio Daroya

The leaves seem to indicate that the plant is suffering from some kind of moisture and heat stress.

Is it exposed to winds? Coupled with the hot afternoon sun, constant winds can dry the plant out despite regular watering at the roots. So you may want to move it to a more sheltered location where it is protected from wind. The site should still be sunny and the plant should be watered regularly to ensure the roots do not dry out.

Do check the health of the roots. Healthy roots should appear white and feel solid. Root issues can contribute to the plant's inability to absorb water, leading to symptoms you have described.

Also check that the roots have not totally filled the pot. In such a situation, there is very little soil left to hold moisture for the plant and it should be repotted in a larger pot with fresh soil.

Avoid disturbing the root ball to minimise transplant shock.


Young Pepper Elder plant can be eaten raw as a vegetable


PHOTO: CHAN LEE KIM

What is this plant? The young shoots of this plant recently appeared in my other potted plants. They are thriving despite my not watering them. Are they weeds?

Chan Lee Kim

The plant's botanical name is Peperomia pellucida and it has common names such as Shiny Bush and Pepper Elder. It often occurs as a weed, where it produces seeds readily and they multiply in flower pots if the plants are not removed.

The young tender plant parts can be eaten raw as a vegetable. The plant has various folkloric medicinal uses, but as with many plants, its medicinal properties have not been scientifically studied, hence be cautious if you are using it to treat illnesses.


Chinese Crown Orchid likes sunny spot, well-drained soil


PHOTO: ANTHONY TAN

I found this plant growing in the wild at Zhenghua Park. It looks like a miniature orchid. What is it and how do I take care of it?

Anthony Tan

The orchid is botanically known as Eulophia graminea and has common names such as Chinese Crown Orchid, Grass Orchid and Bawang Hantu.

It is a terrestrial orchid that frequently springs up in areas that have been newly filled with soil. It produces numerous roots and can be difficult to transplant successfully when dug out and moved to a pot.

The plant prefers a sunny location with direct sunlight. At home, you can grow it in a pot with well-drained and moisture-retentive soil.


Keep Nong Nooch Vine in cool semi-shade


PHOTO: TERESA LAU

Why are the leaves of my Nong Nooch plant turning black? They also fall off easily. I have had this plant for many years and this is the first time it has happened.

Teresa Lau

It appears that your Nong Nooch Vine (Petraeovitex wolfei) may be suffering from heat stress and has been allowed to dry out.

Note that this plant prefers to be grown in a semi-shaded and cool location. Ensure the roots are kept moist at all times and do not allow the plant to dry out.

You may find it helpful to mulch the roots with chipped dry leaves or good-quality compost to reduce the rate of evaporation and keep the roots cool. Also, protect the plant if the area you are growing it in is windy.

Did you recently fertilise or spray the plant with a pesticide? An overdose of a fertiliser or pesticide can cause burn marks on the leaves. It is recommended to use a lower dose than what is printed on the label to be on the safe side. For pesticides, spray a small portion of the plant to see if there are any adverse reactions before spraying the entire plant. Spray plants during the cooler part of the day, like in the evening.


Orchid may be suffering from moisture stress


PHOTO: CHEONG YIN PING

I have an orchid plant that was growing well and blooming. Three weeks ago, the leaves started turning yellow and one of the flowers dropped. A few leaves have also dropped and I do not see new roots growing. What should I do to revive this plant?

Cheong Yin Ping

Your plant is grown using charcoal chips, which dry out quickly.

If it is grown in a high-rise apartment that gets a lot of sun and wind, the roots tend to dry out too fast and the plant will experience moisture stress.

During hot and dry weather, you may want to provide some shade and increase the frequency at which you water the plant. Mist the growing location to cool it down and increase the ambient humidity.

• Answers by Dr Wilson Wong, an NParks-certified practising horticulturist and park manager. He is the founder of Green Culture Singapore and an adjunct assistant professor (Food Science & Technology) at the National University of Singapore.

• Have a gardening query? E-mail it with clear, high-resolution pictures of at least 1MB, if any, and your full name to stlife@sph.com.sg

A version of this article appeared in the print edition of The Straits Times on January 26, 2019, with the headline 'Root Awakening'. Print Edition | Subscribe