Consider performing hand pollination

Why does the fruit of my pumpkin plant turn yellow and fall off before ripening? I keep the plant in a big pot with full sunlight, water it daily and fertilise with compost or chicken manure fortnightly.

Julia Lee

The ovary of the pumpkin female flower may not be swelling due to a lack of proper pollination. Bees are the primary pollinator of your plant’s flowers. If there are no pollinators, you will need to perform hand pollination, in which you transfer pollen from male to female flowers. You can refer to step-by-step videos online.

Repot Monstera deliciosa

My Monstera deliciosa seems to have two main growth nodes. For the first, the new leaf has a small rip. Can this be repaired? How long will the new leaf take to unfurl?

For the second, it appears to be sprouting a fresh shoot and an aerial root. Should I leave the root alone or manoeuvre it into the soil?

Finally, can these all be kept in the same pot or should I move one of the main stems out?

Sam Yeo

The damaged leaf of your Monstera plant will not heal. Handle your plant carefully to minimise damage. The new leaf will unfurl once the plant’s root system is stable.

Leave the aerial root alone. This plant grows as an epiphyte and it is normal for the plant to produce some aerial roots.

You can pot the two plants separately, preferably before their root systems grow and intertwine. If they are tangled, separating them at a later date may damage the roots.

Desert Rose’s stem may be rotten

Why does this adenium have black mould on its trunk? The plant is in a bright sunny spot. How can I get rid of the mould?

Audrey Ng

Is the blackened part of your Desert Rose’s (Adenium obesum) stem soft? If so, the part could be rotten.

This can happen due to prolonged wet feet experienced by the plant after rain. The soil could also have compacted over time and led to poor drainage.

There is little you can do now. You can cut the healthier, upper part of the plant and try to root it. Cut until you see healthy tissue and allow the wound to heal before potting it. However, this method of propagation will not give rise to a plant with a fat basal stem, like your current plant.

Alternatively, you can try to graft growth from this Desert Rose to another plant with a swollen caudex to achieve the same look, though this is a complex procedure typically attempted only by experienced growers.

Air plants need light and air circulation to thrive

I have had the air plant on the left for years. It had small purple flowers at first, but these have not bloomed for a long time. I just acquired another air plant with a red flower. How do I care for my plants in such a way that their flowers continue to bloom?

Wee Cheng Kee

The plant on the left is Tillandsia ionantha, while the one on the right is a hybrid named Cotton Candy.

Air plants require filtered sunlight for at least four to six hours a day. You can mist them thoroughly with water to ensure they stay hydrated. Air circulation is crucial to prevent plants from rotting.

Plants will flower when they are large and robust enough. Optimal growing conditions are required for this to happen.

Figs eaten mostly by animals

I saw this plant at the Bukit Timah Nature Reserve. What is this tree and are its fruit edible?

Chris Seah

The tree could be either a Common Yellow-stemmed Fig (Ficus fistulosa) or Common Red-stemmed Fig (Ficus variegata). Both look very similar and can be distinguished by how the figs appear when ripe.

The fruit of the Common Yellow-stemmed Fig turns yellow-orange when ripe, while that produced by the Common Red-stemmed Fig turns red. These fruit are eaten mostly by animals, not humans. They are not as palatable as the store-bought ones produced by Ficus carica.

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