Propagate Indian Borage through tip cuttings
When I bought this plant, it was growing only upwards without any shoots and was so lanky, I had to cut part of it off. Still, it did not sprout new branches. What plant is this? Is it mint? The stems were hardy. Is it an edible or ornamental plant? Also, how do I propagate it? The cuttings did not root, but rotted when I put them in water. The plant has since died.
The plant is commonly called the Indian Borage. Its botanical name is Plectranthus amboinicus and the plant is commonly mistaken for the common mint plant (botanical name: Mentha cultivar).
What you have is the variegated version where the leaves are edged with white. It can be grown as an ornamental, as well as a medicinal and culinary herb.
The Indian Borage is reported to be used as a substitute for oregano and locally, it is best known for its use to treat coughs.
The plant is best propagated by taking tip cuttings, which refer to stems that have a growing tip.
Some plants may not grow so easily when internodal cuttings are used, which are those you have in the flower pot.
Tip cuttings have been observed to produce roots when placed in water.
It is vital to change the water regularly. Do not submerge any leaves in the water as these will rot and contaminate the water.
This plant should be grown in a location with filtered sunlight for at least four hours daily. The lack of light will lead to unhealthy plants with soft, floppy and elongated stems.
Do not take cuttings from such plants as the stems will wilt quickly and become infected easily. Most of the time, they will fail before they have a chance to produce roots.
African tulip tree once often grown in Singapore
This tree has been growing in my garden. May I know its name and origin?
The young sapling appears to be that of an African tulip tree (botanical name: Spathodea campanulata). Its seeds are wind-dispersed and they germinate readily.
The plant can grow into a tree up to 25m tall with rather attractive, orange cup-like flowers.
It was once grown in Singapore's parks and gardens. In the past, children used the tree's flowers as water pistols and its opened seed pods as toy boats.
If this sapling is growing between a narrow gap of a concrete structure in your premises, you may want to remove it so that its roots do not cause damage in the future.
Pomegranate plant needs more sunlight
I had my pomegranate plant cut down as it was diseased. Now, it has some offshoots and most of them do not look like they are pomegranate. What are they?
The young leaves seen on the plant are those of the pomegranate (botanical name: Punica granatum).
The stems and leaves appear light green and may feel soft at this stage. Note that the pomegranate plant requires a site with at least six hours of direct sunlight.
The current location of your pomegranate plant may be too shady.
The lack of sunlight will lead to soft growth where the leaf-to-leaf distance on the stems will be much wider than those exposed to direct sunlight. Such tender leaves will also be prone to attacks from pests.
Singapore Rhododendron a native plant
I have a tall plant growing in the same pot as the desert rose. It is growing taller and I am curious what kind of plant it is. The
surfaces of the leaves are rough. I am also not sure if I should pull it out.
Puah Toh Peng
The plant is likely the Senduduk, which is also known by a number of common names, including the Singapore Rhododendron. Its botanical name is Melastoma malabathricum.
It is a native plant of Singapore that produces attractive, pink flowers. There is also a variety that produces white flowers.
The seeds of this plant could have been dispersed by birds which consumed the plant's ripe fruits.
They could have landed in the soil of your desert rose plant and germinated.
If the plant is still small, you can carefully transplant it with as big a root ball as possible - this will reduce the impact of transplant shock and ensure a higher likelihood of the plant surviving after the process.
The Senduduk prefers a sunny and moist location to grow well.
Lettuce plant infected by a fungal or bacterial disease
Some of my curly kale leaves recently turned yellowish brown at the edges. What could be causing the problem? Is the rest of the leaf still edible after I remove the brown parts?
The leaves of your lettuce plant may have been infected by a fungal or bacterial disease. A closer examination at the laboratory will be required to ascertain the exact causative agent of the disease.
For now, to reduce the spread of the disease, you may want to prune infected portions of the leaves with a sterile pair of scissors. Sterilise the pair of scissors again before using it to prune other plants.
The leaves are edible after cutting away the infected parts.
Ensure your plant gets sufficient sunlight, which is needed for healthy growth. Provide ample air circulation and give some space between the plants. Take care to reduce soil splashes onto the leaves and protect the plants from the direct impact of rain.
• 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.
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