Category Archives: Root Awakening in ST Life!

Below are my answers to three gardening questions to the second instalment of the Root Awakening column for Mar 2010.

The first question asked about the identity of a tree found growing in the vicinity of the Regent Hotel on Cuscaden Rd, Singapore. That tree is a popular landscaping candidate that is commonly called the ‘Happiness Tree’ and ‘Philippine fortune tree’. It thrives in semi-shade and well draining soil conditions. Botanically known as Garcinia subelliptica, it is a close relative of the common mangosteen and is a slow-growing, medium-sized tree with evergreen, thick and leathery oval leaves. It has one main trunk and adopts a compact and conical crown. Interestingly, it was once planted to form a windbreak in the Okinawa islands, Japan.

The second question asked about a problem – yellowing leaves – encountered during the cultivation of a chilli plant. It is important to ensure that one’s chilli plant is well hydrated at all times. Plants that have suffered severe drought conditions often develop yellowing leaves which are shed subsequently. There may be a need to water your plants more than once daily if it is grown in a windy and sunny location.

One may also want to take the plant out of its pot to check for soil mealy bug infestation as these pests impair a plant’s ability to uptake water. When there is a prevailing infestation, the roots of your plants will have white patches surrounding them. A safe and organic but rather slow method that can be used to treat infested plants is to use diatomaceous earth (available from Known You Seeds (S.E.A.) Distribution). Diatomaceous earth is an inert, non-volatile, powdered substance made from the skeletal remains of diatoms, which have been processed to form razor-sharp particles which cut into the bodies of small insects. Avoid breathing in the dust.

To treat for soil mealy bugs, carefully wash off infested soil from your plants roots and then repot your plant in a soil that has been mixed with diatomaceous earth. Use about 1 tablespoon per one liter of soil. Note that large chilli plants can suffer from transplant shock during the root washing process.
Soil mealy bugs can be difficult to eradicate and badly affected plants should be discarded. Sterilise pots and soil before using them to pot up new plants.

The last question was about mosquito plants. Note that no plant (common ones include Pelargonium citrosum and citronella grass) in existence will repel mosquitoes by sitting in a pot or a corner in a garden. Many plants touted to repel mosquitoes are due to the fact that they have significant amounts of repellent essential oils in their leaves. The repellent effects will only be observable when their leaves are crushed or heated where the essential oils are released into the air.

In this weekend’s Root Awakening column, answers to three gardening questions were given. The first question dealt with the spraying of pesticides by our neighbours. Note that pesticides vary in terms of their toxicity and all should be treated as harmful. One should advise his neighbor to inform him whenever a pesticide application will be performed so that the necessary precautions can take place. It would also be useful to know the type of chemical that is being applied so that you can do some homework to know what protective measures to take. Some pesticides are very toxic to fish and aquatic life so make sure pesticide fumes do not reach them.

The next question was about a local medicinal herb, which is botanically known as Gynura procumbens. It is a plant that is a member of the daisy family, Asteraceae, which is eaten as a leafy vegetable in some parts of the world. To date, its cancer-curing properties have not been systemically assessed and proven. This plant is also believed to be able to reduce high blood pressure and lower serum glucose levels, amongst others. Further studies need to be performed to confirm such effects. It is best to consult a certified practitioner before consuming such herbs.

The last question queried about the identity of a houseplant with purple foliage. Botanically known as Oxalis regnellii ‘Atropurpurea’, this particular houseplant is known via a range of common names that include Purple Oxalis, Wood Sorrel and False Shamrock. It is native in Argentina, Bolivia, and Paraguay and can be propagated via division of the crown. Grow it in a protected, semi-shaded location away from winds. It prefers to grow in a well-drained soil mix such as one concocted for container gardening. Keep soil moist at all times and not soggy. Fertilize weekly with a balanced fertilizer.

Three gardening questions were provided with answers for this week’s Root Awakening column. The first question dealt with the choice of fruit trees that are suitable for growing in a rooftop garden in Singapore. For this, I suggested some small fruit trees that are more rewarding to grow in pots which include the chiku, kedongdong, guava, jambu and starfruit. Grafted versions of the mango can also be considered. Another fruit plant to grow is the dwarf Cavendish banana. It is important that fruit trees should be located in a location where they are able to receive at least 6 hours of direct sunshine and soil that is kept moist at all times. Note the weight bearing capacity of one’s roof-top before populating the area with large pots of fruit trees.

The second question was about the choice of plants for a east- or west-facing growing location and the range would largely depend on the duration and intensity of sunshine that are available. If the area receives direct sunshine for at least 4 hours daily, one can grow a large range of plants which include flowering shrubs and vines and selected vegetables and herbs. Fruit trees can be difficult as they require longer duration of direct sunshine.

Note that many foliage plants need some form protection under such high light conditions to prevent foliage burn. They can be grown on the lower tier of your growing rack or between taller plants which can offer some shade from direct sunshine. I referred readers to grab the book entitled ‘1001 Garden Plants of Singapore’ published by the National Parks Board for the range of plants that one can grow in a balcony. The light requirement of each plant is indicated by an icon in the book.

The last question was about the lack of fruit set in tomato plants. This is a commonly encountered problem in Singapore. It is important to note that not all tomatoes will be rewarding to grow in Singapore’s climate. Only the smaller fruited cherry tomatoes seem to set fruits well here. Larger fruited ones usually experience poor fruit set as flowers tend to drop off without turning into fruits. To help pollination, it may be beneficial for one to perform hand pollination by using a fine paintbrush to brush each opened flower to help transfer pollen which will increase the chance of fruit set.

Note that the first few flushes of flowers tend to be aborted but fruit set should start soon after that.

The third and last instalment of the Root Awakening column for Jan 2010 was published today.

The first question was about the growing of hibiscus plants from stem-cuttings.  Hibiscus can be propagated via both softwood and semi-hardwood stem-cuttings. Softwood cuttings are taken from soft, succulent, new growth. Shoots are suitable for making softwood cuttings when they can be snapped easily when bent and when they still have a gradation of leaf size (oldest leaves are mature while newest leaves are still small). They usually root faster than semi-hardwood cuttings.

Semi-hardwood cuttings refer to stems taken from partially mature wood. Such stems are reasonably firm, the leaves of mature size and may have some bark on them. Avoid material with flower buds if possible and remove any flowers and flower buds when preparing cuttings so the cutting’s energy can be used in producing new roots. Take cuttings from healthy and disease-free plants. Take stem-cuttings from plants that have been well-watered and do so in early morning when it is cooler.

Cuttings are best around 4 to 6 inches long by using a pair of sterilized sharp pruning shears. Remove the leaves from the lower one-third to one-half of the cutting. Cut large leaves in half to reduce water loss. Dip the cut end of a stem-cutting with some rooting hormone powder made into a slurry.

Stick stems into a new soil mixture that is sterile, low in fertility, and well-drained to provide sufficient aeration. Insert the cuttings one-third to one-half their length into the medium and maintain the vertical orientation of the stem. Cover the cuttings with a plastic bag and place in indirect light. Keep the medium moist until the cuttings have rooted. Rooting will be improved if the cuttings are misted on a regular basis.

Rooting time varies with the type of cutting, the species being rooted, and environmental conditions. Grow cuttings in a pot until they attain a larger size before transplanting to a permanent location.

The second question was about the shrivelling of leaves of a tree. It could be due to hot and dry weather. Under such weather conditions, it may be beneficial to ensure the plant is well-watered and roots are kept moist. Do also apply a layer of mulch around the root zone to ensure it stays moist and cool. If possible, provide some form of shade during this period. It could also be due to a bout of insect infestation and hence it would be necessary to check if there is any and ensure that all pest infestations have been cleared. Any remaining population can re-infest a plant if not properly eradicated. Several rounds of pesticide application may be necessary.

The last question was about the pruning of a money plant. A money plant will not die if its growing tip has been cut. The plant will respond by producing side shoots and this can take any time at least two weeks, depending on the growing conditions. Cutting back a money plant can be beneficial at times as it helps to keep a plant’s growth in check and can help to maintain or promote a bushier growth habit.

The second instalment of the Root Awakening column for Jan 2010 was published yesterday. As usual, answers to three gardening questions were provided.

The first question was about the growing of the flaming beauty (Carphalea kirondron), which is a sun-loving shrub that is also a heavy feeder. It prefers to be grown in consistently moist soil that is enriched with well-rotted compost. One has to watch out for small sucking insects such as aphids, mealy bugs and white flies that may feed on young, emerging shoots. Attacks by these pests can cause new growth to die back. Spray with neem oil or white summer oil to eradicate these pests.

The second question was about a reader’s proble in growing of a rose said to be from Kunming. Note that the rose plant needs to be protected from the tropical mid-day sun. Roses like to be grown in a sunny area with moist, well-draining, fertile soil that is supplemented with organic matter such as compost. One can fertilise plants with a suitable rose fertilizer or water-soluble ones like Gaviota and Phostrogen, made up according to the manufacturers’ instructions. Heat can be a serious problem with roses during the hot season where new shoots and buds can dry up as a result. Grow in pots so that it is easier to move plants to semi-shaded areas during that time.

Also, rose plants are commonly affected thrips or spider mites that commonly attack young growth and new flower buds of rose plants. To eradicate these pests, Condifor (active ingredient is imidacloprid), which is a systemic pesticide has been found to be particularly effective. Before spraying, it is best to prune away affected parts so as to reduce the population of pests.

The last question dealt with the lack of flowers of a yellow frangipani plant. Note that this plant is a sun-lover and one has to ensure his/her frangipani plant receives sufficient duration of direct sunshine. A recommended duration would be at least 6 hours daily. It would be beneficial to feed the plant with a fertiliser to promote flowering that is high in phosphorous content. Refrain from fertilizing your plant with only organic fertiliser which is usually rich in nitrogen that promotes growth of foliage. Make sure that the soil pH is right so that nutrients required for growth are not locked up or in excess which will affect the plant. The optimal pH range for frangipani is from 6.4 to 6.8.

The first instalment of the Root Awakening column for 2010 was published today.

The first question dealt with white insects on kangkong plants and this could be an infestation of white flies. To eradicate these pests, spray plants using white summer oil or neem oil. Make sure you cover every part of the plant thoroughly, including the leaf undersides as well as any spaces between leaves. There is also a need to repeat application of the pesticide several times to ensure all progeny that hatch from eggs laid earlier are also eradicated. Check surrounding plants for any signs of infestations as well. Pests from these plants can migrate over at times. They should be sprayed as well if there is any signs of infestation. Alternatively, this could be a fungal disease called white spot that commonly occur in kangkong plant. Note that the spots are not mobile and cause the upperside of leaves to have yellow spots.

The second question was about the growing of the rangoon creeper in a container. Note that the Rangoon creeper is a big vine and it may not be a good idea to constrain it in a pot as it will be likely to suffer from water stress. A plant that has grown larger with a dense crown of foliage tend to have a higher demand for water as it transpires more. The amount of water that can be retained by the soil in a pot may not be sufficient for the plant’s needs. A plant that has been allowed to dry out may show yellowing leaves or shed its lower leaves. It is hence necessary to transplant your vine into a larger pot. One may want to transplant your plant into ground if it has grown too big. For plants grown inside a small pot, do increase the frequency of watering and apply a layer of compost on top of the soil surface to act as a mulch, which can help to retain water and reduce rate of evaporation.

The last question was about the growing of orchids. It is definitely not true that orchids do not require fertiliser. In fact, many species and hybrids need to be feed to grow healthily and produce flowers. Some fertilisers that are good for orchids include Gaviota (available from Far East Flora).

This orchid is an epiphyte and it is likely to be grown in a porous mixture such as  charcoal chips and this dries out quite quickly. Depending on the growing conditions, it may be necessary to water it at least twice daily, especially it is grown under direct sunshine. The problem described by the reader seemed to suggest that his/her orchid plant may be suffering from heat and moisture stress. One can consider adding a little sphagnum moss around the root zone to help retain some moisture. It may be necessary to increase the frequency of watering too. Do also try to relocate the plant to a less windy area or provide some protection by putting up a barrier to wind by growing them amongst some plants.

Do check out the book published by the Orchid Society of South East Asia entitled ‘Orchid Growing in the Tropics’ for more information on how to grow various orchids in Singapore.

 The second instalment of the Root Awakening column for December 2009 was published today. The first question from a Straits Times Life! reader was about how festive citruses can be made to bear fruit while they are still small and seemingly young. Most of such plants are generally grown on a grafted rootstock. This rootstock is usually a vigorous citrus plant such as lemon and shoots from mature trees that are already flowering and fruiting are taken and then grafted to this rootstock.

The second question was similar to previous questions that have been published. It was about why the inflorescences of one’s orchid plant tend to turn brown and then die away. The problem is likely to be caused by excessive heat and moisture stress. Adding a little sphagnum moss around the root zone to help retain some moisture. It may be necessary to increase the frequency of watering too. Do also try to relocate the affected plant to a less windy area or provide some protection by putting up a barrier to wind by growing them amongst some plants. Check for spider mite and thrips infestations as well.

The last question dealt with the small, cottony insects that appear on a custard apple plant. The pests seen are likely to be mealy bugs. To eradicate these pests, one can spray infested plants using white summer oil or neem oil. Make sure every part of the plant is covered thoroughly, including the leaf undersides as well as any spaces between leaves. There is also a need to repeat application of the pesticide several times to ensure all progeny that hatch from eggs laid earlier are also eradicated. Check surrounding plants for any signs of infestations as well. Pests from these plants can migrate over at times. They should be sprayed as well if there is any signs of infestation.