SINGAPORE - Here are this week's gardening queries.
Scale insects on bamboo
There are bugs (above) on my bamboo shoots. Is it due to the wet season? I have sprayed a sulphur soap solution and neem oil occasionally. How can I get rid of the bugs and will they infest my other plants in the garden?
Tan Boon Keng
The bug is likely a type of scale insect which sucks sap from the plant.
A heavy infestation will probably lead to sooty mould which appears as black, sticky patches on surrounding plants.
Stresses from the environment may weaken plants from time to time, leading to increased infestation by pests. The lack of predator activity during the rainy weather may also be a reason.
Some of these pests are highly specific and do not infest nearby plants. Nonetheless, it is good to inspect the surrounding plants to be sure and take appropriate action if the same pest has been spotted.
Low-toxicity pesticides like neem oil and summer oil are quite effective as they suffocate the pests. But regular applications, which should be thoroughly applied with good coverage, are essential for effective control.
Plant grown is pumpkin vine
I sowed the seeds of a known pumpkin but instead of a pumpkin plant, this one sprouted (above). It looks like pumpkin and has several flowers, but they never blossomed. What plant is it and is it a different kind of pumpkin? How do I get it to bloom?
From the leaves of the plant, what you have is the pumpkin vine. Plants will bloom when the vine gets large enough. Ensure that the plant receives at least six hours of direct sunlight for robust growth. Usually, the male flowers appear first before the female ones. You may need to hand-pollinate the plant to encourage fruit production if natural pollinators such as bees are absent. A way to keep track of the plants you have sown is to write down the name of the seeds and the date which they are planted.
Luck plant has medicinal uses
I am told this plant (right) is edible and has medicinal properties to cure intestinal problems. What is it and can it be eaten? Does it have medicinal properties?
Tea Ann Lee
The shrub is commonly known as Luck Plant or Wild Hops. Its botanical name is Flemingia strobilifera. It grows as a shrub and produces attractive, hanging inflorescences with overlapping bracts that hide the true flowers. The plant has medicinal uses - its leaves are reported to be administered after childbirth and used for bathing the body. It is also used to treat rheumatism.
Ludwigia species is a shrub
What plant (above) is this in my flower bed? It grows quickly and has large leaves that close at night. Is it a flowering or fruiting plant, and is it poisonous? I am wondering if I should discard it in case it grows into a tree.
From the appearance of the leaves, the plant is probably a Ludwigia species. Locally, you can see two species, namely the Ludwigia hyssopifolia (Water Primrose) and Ludwigia octovalvis (Primrose Willow). Both plants produce yellow flowers, grow in wet soils and may appear as weeds in a flower bed. They also grow as shrubs and are not likely to damage walls and other structures. They are generally not regarded as toxic plants.
How to tell the difference between dill and dogfennel
I have a plant that was given to me a long time ago. I have taken it to be dill and have used it occasionally for cooking. It had the fragrance of dill. How can I tell the difference between dill and dogfennel plants?
The dogfennel grows as a shrub with upright stems and light green feathery leaves. The true dill grows as a small herbaceous plant with its leaves arranged in a rosette manner arising from a rootstock. Its leaves are bluish green.
For further details, you can refer to the article on the National Parks Board's Flora Fauna Web, Eupatorium capillifolium and Anethum graveolens. You can find it under the tab, Comparison Of Similar Looking Plants, after clicking on the Resources tab at the top right hand side of the homepage.
- Answers by Dr Wilson Wong, an NParks- certified practising horticulturist, parks manager and ISA-certified arborist. 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. We reserve the right to edit and reject questions.