This is the the last instalment of the Root Awakening column for the month of June 2011. Answers to two questions were provided.
The first question was about why the leaves of a frangipani showed signs of drying up. This could be a sign of a mealy bug infestation. One may want to check the undersides of the leaves for an infestation of mealy bugs which suck sap from leaf tissues. They appear as white cottony masses that congregate along the mid-rib and veins of leaves. Leaves that have been attacked often become warped and deformed and they finally dry up and fall off. Control the population of such sucking pests by spraying the underside of leaves with white summer oil (organic) or any other pesticide that is indicated for treatment of mealy bug infestations. You may want to remove and discard badly infested leaves before spraying to reduce the amount of pests to be dealt with.
Another point to add is to check for infection by the rust fungus. Severely infected leaves will eventually dry up and fall off. One should make an effort to remove all infected leaves as the spores from infected leaves will go into the soil and infect other frangipani plants.
The second question was about curling and yellowing of the leaves, as well as, deformation of flowers seen in the hibiscus plant. The symptoms described may be indicating that the plant is lacking in certain mineral nutrients. To correct the problem, one may want to feed plants with a water-soluble fertiliser that contains chelated elements. Look at the ingredient list on the fertiliser’s label. The correction of a severe deficiency may take many months. The symptoms of any minor element deficiency show up on the new growth with the new and younger leaves being affected. When the deficiency is corrected, the new growth will be normal in appearance.
Note that even with a good feeding programme, nutrient deficiencies can still occur due to changes in soil acidity, organic content and drainage. As Singapore’s soil is often clayey and compacted, it is beneficial to improve the quality of soil by the addition of organic material such as good quality compost. Compost is valued for its soil conditioning value. Incorporate compost into the top few inches of soil to improve its properties.
One more point to add is to check also for mealy bug infestations in the leaves. Infestations by sucking insects will also cause leaves to become deformed.
Here’s the Root Awakening column for the second week of Jun 2011 and answers to two gardening questions were given.
The first question was about the ability to grow plants in a lift landing in a HDB apartment block. Unfortunately, there are not many plants that will thrive under the dimly lit conditions commonly encountered. Note that the ceiling fluorescent lights that are turned on at night in HDB corridors are usually not intense enough to support plant growth.
Many plants will deteriorate after some time after being located in such a condition. If it is possible, do a rotation between groups of plants to be displayed in your lift landing. After being displayed for a week or two in the dim lift landing, you can shift them to a brighter place to recuperate. Note that many sun-loving plants will quickly deteriorate when they are placed in the shade, even for short durations.
To grow a plant successfully in a given location would depend on its light requirements. Its leaves need to be exposed to the light rays of either filtered sunlight or direct sunlight for at least for 4 hours daily, as a general rule of thumb. For most apartment dwellers this would involve putting the plants just next to the parapet and raised from the floor so that they can be exposed to sunlight that streams through into the growing area.
The second question was about the existence of anti-mosquito plants. My answer is no. There is no plant that will repel mosquitoes on its own. The range of plants that are reported to possess mosquito-repelling properties do so only after the leaves have been picked and crushed to release the essential oils.
Here’s the Root Awakening column for this week where two gardening questions were given answers.
The first question dealth with the identities of two commonly encountered shrubs which are great hedge plants. One of them is Syzygium campanulatum and there are two cultivars available currently. One has orangey new leaves whilst another has maroon new leaves. Both the orange and maroon cultivars have become quite popular shrubs for landscaping in Sinagpore. They are best grown in a sunny, well draining spot to ensure the leaves put forth their vibrant colour. Some people prune the shrub regularly to promote new colourful foliage growth.
Another hedge plant identified was Baphia nitida. It is an ‘old school’ plant that has been around for quite some time and is fondly remembered for its use to screen away rubbish points in public housing estates in the past. It is a highly versatile shrub as it also thrives in shady areas.
Both shrubs are easy to grow and relatively fuss-free. But Syzygium campanulatum may occasionally get attacked by caterpillars or beetles.
The second question was about the effect of putting ice cubes on the root zone of a bamboo plant with the hope that the leaves will be greener. As far as I am aware, there is no scientific evidence to support such a claim. Excessive chilling of roots can do more harm than good. Yellowing bamboo leaves can be brought about by a variety of reasons, such as by the lack of certain nutrients, and it is best to find out the root cause and remedy it.
The Root Awakening column for the second week of December 2010 provided answers to two gardening questions. The first question queried on how to go about to start the gardening hobby and be successful in it. My advice given was to first learn more about the plants that one is interested in growing. One should start off by getting their names right and get to know about each plants’ growth requirements. A good reference to look to is the NParks’ publication entitled ‘’1001 Garden Plants of Singapore’. It is a pictorial guide which makes reference by anyone very easy.
To better grow one’s plants, it is best to follow this guideline – grow the right plant in the right location. Understand the conditions in your growing area at home and choose to grow plants that are suited for that area. One should check out and take part in the gardening talks and workshops conducted by HortPark and Singapore Botanic Gardens as these are organised with budding gardeners in mind.
The second question touched on why young fruits of the custard apple tree failed to develop fully. Most would turn black and become aborted. From what I have researched, the custard apple tree is well known to be a plant that prefers a sunny, well-draining location. The symptoms the enquirer has described seem to point to overwatering or a plant that is grown in a waterlogged location. It is advisable to the plant to grow in a location with better draining soil and allow plant to dry out a little between each watering, especially in Singapore where we are located in an area with high rainfall.
Answers to two gardening questions were provided in this weekend’s edition of the Root Awakening column. The questions pertained to problems faced in growing chillis and the bauhina vine.
The problem mentioned in the first question is a common one. Often, the first flushes of flowers in the chilli plant often fall without bearing any fruit. Chilli plants usually has little problem in setting fruits in the lowland tropics. Hence this problem should resolve itself in subsequent flushes of blooms. Otherwise, it may be a case of poor pollination. One can perform hand pollination by using a small paintbrush to brush each flower to help transfer pollen. Other causes could be due to dry air caused by windy conditions.
The second question was about the new growth in Bauhinia kockiana not growing well and tips of older leaves turning black. The enquirer mentioned about once fortnightly feeding. With the information given, the black leaf tips may be a sign that the plant is over-fertilised and hence it is recommended to follow the instructions printed on the label of the fertiliser. In general, Bauhinia kockiana is a plant that will grow better if it is grown in the ground and it is vital to keep the roots cool by mulching it with compost. Avoid trimming new growth as this is where flower buds will be formed.
As usual, asnwers to three gardening questions were given in yesterday’s instalment of the Root Awakening column. The first question asked why there were ants around a basil plant which also exhibited the drying of leaves. I suspect it could be an infestation of 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.
Note that the presence of ants are a signal of a prevailing aphid infestation as they are attracted to the ‘honeydew’ secreted by aphids. Spray with neem oil or white summer oil to eradicate aphids. You may need to cut back some growth to reduce the pests before spraying.
The second question was about the appearance of flying insects in mangoes. It is likely to be a case of fruit fly attack. These insects lay eggs while the tree is flowering. One can help to reduce the incidence of attack by constructing a fruit fly trap using a plastic bottle. Burn several holes in the middle of the bottle using a heated screw driver. Inside the cap, dangle a cotton bud soaked with fruit fly attractant (available from major nurseries) and fill the base of the bottle with some water. Add a little cooking oil to cover the water surface to prevent mosquito breeding. Fruit flies attracted to the fruit fly attractant will visit the plastic bottle via the small holes burnt into it. Some will be trapped and drown inside the small amount of water found at the base of the bottle.
The final question dealt with the lack of fruits in a tall chilli plant. Note that chilli plants usually start to fruit when they are about 3 months old, depending on the variety as well as growing conditions. It is vital that a plant is able to receive sufficient direct sunshine (for about 4 to 6 h daily) so as to prevent the stems from etiolating.
Three questions were provided in this week’s Root Awakening column.
The first dealt with the growing of the florist’s gloxinia. It is a common misconception that the florist’s gloxinia has the same growing conditions as the African violet. This is especially true with regards to its light requirement. Unlike African violets, the florist’s gloxinia require more light to grow well. It thrives under semi-shaded areas outdoors and indoors, it should be exposed to filtered sunshine for at least 6 h daily. Plants grown under shadier conditions will etiolate, i.e. become lanky and vine-like.
The flowers of the florist’s gloxinia are easily affected by fungus disease when the buds or petals are wet. When one is watering a plant, avoid splashing water onto the flowers or buds. It is also recommended to grow a plant in an area with ample air circulation. Affected flowers and buds should be removed promptly to reduce the likelihood of the problem from spreading.
The next question was about the appearance of mealy bugs on a dracaena plant. Mealy bugs can infest plants that are not healthy or they can come from surrounding plants. First and foremost, make sure your plant is grown under optimal conditions. Healthy plants are less prone to problems. To eradicate pests from plants via pesticide spraying, 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. It is recommended to also 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.
The last question was about the growing of mango trees from seeds. It is vital to know that fruit trees, such as mangoes, grown from seeds need to attain their full height and size before they flower and fruit. The fruiting habits of trees grown from seeds can vary as some are more rewarding whilst others may not. It is more reliable to grow grafted fruit trees as these trees have the growing stock of a good fruiting specimen. Grafted trees are generally able to fruit earlier too.
The first Root Awakening question was about flowering and fruiting of jambu and custard apple trees. It is important to note that jambu trees produce bisexual flowers while custard apple trees bear both male and female flowers on the same tree. Flowers that fall without formation of fruits are an indication that the flowers have not been pollinated.
The flowers of jambu are pollinated by bees while custard apple flowers are pollinated by beetles. One should refrain from spraying pesticides in the garden as these chemicals can affect the population of these pollinators.
Excessive foliage on a fruit tree is a sign of over-fertilization with nitrogen fertilizer. Note that many organic fertilizers are rich in nitrogen. To promote flower and fruit production, switch to a flowering fertilizer that is higher in phosphorus content.
The second question dealt with potted fruit trees which came with fruits but produced no further ones after one brought it home. Many potted fruit trees are grafted ones and a grafted tree may come from a branch already about to fruit from the parent plant. This could lead to early fruiting on the grafted branch. The new plant will need to grow until it is sufficiently mature before it gives more fruits. Fruit drop could be due to moisture stress during fruit development. Fruit trees that are not well watered during hot and dry weather can become stressed and they abort their fruits as a result.
It is recommended to lay a ring of organic compost as a mulch around the root zone to help keep the tree roots moist and cool and all times. Water your fruit trees more frequently during hot and dry weather. Compost will break down over time and release nutrients to your trees.
The last question asked about the growing of thyme in Singapore. Many culinary herbs require full sun to grow well. Plants exposed to direct sunshine for at least half a day will produce compact and fragrant foliage for use in the kitchen. Herbs native to the Mediterranean region can be grown in tropical Singapore but they need to be planted in very well-draining soil. Most need to be protected from heavy rain outdoors.
Fresh herb cuttings can be dipped in a jar of clean tap water. Remove the some of the bottom-most leaves to reveal the nodes for rooting. Most stem-cuttings derived this way will root within a period of 1 to 3 weeks and these can be potted up in soil separately. A good selection of culinary herbs can be purchased from HortMart (at HortPark), Oh Chin Huat Hydroponic Farms Pte Ltd and World Farm Pte Ltd.
The third instalment of the Root Awakening column for the month of August 2009 was published last Saturday on Straits Times Life! As usual, answers to three gardening questions were provided.
The first question dealt with cone-like creatures that were found in the soil of a potted plant. I reckoned it could be snails and one can put in some snail and slug baits on the soil surface that will help to eradicate these garden molluscs. One has to be careful to not allow one’s pets and young children to have access to the pellets after they have been applied to our garden plants.
The second question was sent in by a reader who described the presence of brown circles that appeared on his/her plant. Without a picture, I could only guess that they could be brown scale insects and these can be easily eradicated using white summer oil, white oil or neem oil which work by suffocating these pests. One has to remember to repeat the application at periodic intervals so as to ensure that the progeny are also eliminated as well. Apply these oil-based products only on a cool day and after a plant has been thoroughly watered.
The last question was about distorted leaves that were seen in a perilla plant. It is hard to tell what exactly went wrong but from my experience with it, the perilla plant is not exactly plant to grow here. It seems to do better in cooler climates. The poor flavour described by the reader could hence then be due to climate differences. Most aromatic plants need to be grown under direct sunshine to obtain compact growth and maximum aromatic oil production and extremes in temperature can affect it.
Distortion of leaves seen in the plant is not likely to be caused by the heat encountered in Singapore. It could be brought about by tiny pests such as spider mites and thrips which feed on the young leaves. Once symptoms have manifested, no amount of pesticide will help. One should trim away affected parts and then spray the plant to reduce the likelihood of attack. For edible plants, I would recommend white summer oil for spider mites but for thrips, only Confidor is effective. For the latter, being a systemic pesticide which will be absorbed into the plant, one has to observe the witholding period. This time period has to elapse before one can pick the leaves for safe consumption.
Four gardening questions were given answers in the third and last instalment of the Root Awakening column for the month of July 09.
The first question was about the drying of leaf-tips in a rosemary plant. This is a commonly encountered problem in Singapore which is likely to be brought about by excessive soil moisture. The rosemary plant is a native of the Mediterranean region that is adapted to grow in a cool and dry climate. It can grow well in Singapore provided it is grown in a well-draining soil mix. To be on the safe side, it is best to grow a plant in an area that is sheltered from rain and still able to receive direct sunshine for at least half a day.
The second query asked why soft rotting spots were found on a leaf of an orchid. This problem can arise when leaves are injured by water constantly dripping on the same spot on a leaf. Cut away the affect part of the leaf using a sterilised pair of sectaceurs. Remember to sterilise it after cutting the infected leaf. It may be beneficial to seal the wound from further infection by pathogens by coating it with some fungicide powder.
The third question asked why an asparagus plant was found to be turning brown. In general, asparagus plant (also called asparagus fern) should not be over-watered and needs to be grown in a bright place with some filtered sunshine for at least half a day. Its roots should not be allowed to dry out. An asparagus plant can easily dry out when it is grown in too small a pot where its roots can be seen to come out from the drainage holes found at the base of the pot. In such a case, there is very little soil left to help retain water for the plant. Exceedingly low air humidity may also cause leaves to turn brown.
The last question asked where can one purchase white summer oil. White summer oil is fractionated petroleum oil that has an emulsifier added to it. Currently, the gardener may encounter some problems in trying to buy the product from local nurseries as the products sold are not explicitly labelled as ‘white summer oil’. One should look out for the product that comes with the tradename ‘Acalineum’. Please always follow the instructions given on the label of the bottle. Otherwise, do also check out the Materials Safety Data Sheet (MSDS) that can be found online for a similar product.