Aloe vera has fungal disease
What causes these brown spots (above) on my plant and why do the tips of some leaves dry up and turn brown?
Your aloe vera plant appears to be infected by a fungal disease, which is common in Singapore's hot and humid climate. The damage on the plant is permanent.
To prevent this from happening again, you can try growing the plant under a clear shelter which shields it from excessive rain, which leads to overly wet growing media. The clear shelter still allows the plant to get sunlight.
Aloe vera needs to be grown under good light to do well. Avoid soil splashes and keep the leaves dry.
Tip: Trailing Portulaca gilliesii a good choice for desert-themed plots
Portulaca gilliesii is relatively new to Singapore.
Its leaves, shaped like rice grains, are highly ornamental - they turn deep maroon when exposed to full sunlight.
The plant produces numerous large, electric pink, single-petal flowers (above).
It grows in a long, trail-like formation, which makes it good for a desert-themed garden filled with rocks and well-draining soil.
It is available only from hobbyist plant vendors at HortPark's Gardeners' Day Out.
The next event is at the HortPark (33 Hyderabad Road) on Sept 10 from 9am to 5pm.
Sticky substance is tree's sap
What is this sticky thing (above) hanging from the tree? Can I touch it?
Tang Siew Hong
The tree is botanically known as Araucaria heterophylla, more commonly called the Norfolk Island Pine.
The sticky substance is its leaking sap and was likely brought on by an injury inflicted on the tree.
Most of the time, the sap would have solidified on the tree. It should not be removed to avoid exposing the tree's tissues to pathogens.
It would be beneficial to get a certified arborist to periodically check on the trunk's structural integrity to ensure it is in a good and healthy condition.
Tecoma stans needs full sun to thrive
What is this flowering plant (above)?
It is botanically known as Tecoma stans. It has common names such as Trumpet Bush and Yellow Bells and grows as a lanky shrub with weak, pendulous branches.
It can grow up to 2m tall and often requires some form of support. It needs full exposure to the sun and soil that is well-draining as it does not tolerate prolonged wet feet.
Prune this plant periodically to encourage branching and a bushier growth habit. Tecoma stans does best when grown during the hot and dry season in Singapore.
Kalanchoe pinnata used in folk medicine
When I was younger, I bled after stepping on a rusty nail. My neighbour used a leaf from a plant that looked like this one (above) to make a mash, which she then used on my wound. Is this the same plant? What is its scientific name and what can it be used for? Is it edible?
The plant pictured is botanically known as Kalanchoe laetivirens. Also commonly known as Mother of Thousands, it produces many small baby plants along the leaf margin and can become quite invasive if growing conditions are conducive.
The plant you mentioned is used in folk medicine to treat wounds caused by rusty nails and is a close relative called Kalanchoe pinnata.
They are only superficially similar in appearance. When you put the two plants side by side, their differences will be obvious.
Kalanchoe species are not edible and they may be poisonous if swallowed. These plants have been found to contain substances that are toxic to pets such as dogs and cats, so keep such plants away from them.
• Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore (www.greenculturesg.com). He is also an NParks-certified park manager. He will speak about growing succulents, starting a miniature garden and more at the Singapore Garden Festival this month. General admission to the festival applies (go to www.singaporegardenfestival.com).
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