Gardening with Wilson

This year, National Parks Board (NParks) and National Library Board (NLB)  worked together to present the Bear Fruit (B.F.) series 2009, a process-oriented programme that provides a platform for amateurs and enthusiasts to be inspired and aspire to turn their gardening passion and interest into reality. After a period of about two months, the Bear Fruit (B.F.) 2009 series of activities drew to a close. I was there at the certificate presentation ceremony this evening.

In this year’s series, participants who are largely non-gardeners and come from all walks of life, were introduced into the realm of plants and gardening. After a series of basic gardening talks, participants grouped together to make their first terrariums – gardens inside a sealed environment. In this case, plants were housed inside a glass fish tank. The presentation ceremony featured the various terrariums done by the participants and these will be moved to HortPark soonafter and put on show during GardenTech 2009 (14 to 18 Aug 09).

Guest-of-Honour of the ceremony was Dr N. Varaprasad, Chief Executive of NLB, who presented certificates to the participants for their hardwork and aptitude throughout the series spanning a period of 2 months. Mr Ng Lang, CEO NParks, was present at the ceremony to support the participants and the partnership between NLB and NParks. Resource speakers who shared basic gardening and design tips were myself and Thomson Lim (both from NParks). Like me, Thomson was also there to support the participants.

Senecio macroglossus is a vine that is often featured in houseplant books but is seldom sold in the plant nurseries in Singapore. When it is not in flower, the foliage of Senecio macroglossus resemble those found on an English ivy, which are smooth and fleshy to touch, and have five pointed corners. Because of this characteristic, this vine is referred to via a range of common names which include cape ivy, Natal ivy and wax vine. When broken, both the leaves and stems are said to release a lemony scent.

Botanically, Senecio macroglossus is classified as a member of the daisy family (Asteraceae) whereas the English ivy, botanically known as Hedera helix, belongs to the Araliaceae family.  The plant that I have managed to have a look was the variegated version that had some flowers on it. Each blossom looked like a large, pale yellow daisy flower which is reported to remain open on cloudy or dull days and visited by bees, moths and wasps.

Like many other but not all Senecio species, the seeds borne by this plant are wind-dispersed and look like little sticks with a tuft of grey or white hairs attached to one end (called pappus). These hairs help the seeds to catch the wind. The genus name Senecio is derived from the Latin word ‘senex’, which has the meaning of ‘old man’ due to pappus found on the seeds. The species name macroglossus means large-tongued which probably refers to the large size of each leaf.

Although it is a drought-tolerant plant that is native to South Africa, Senecio macroglossus is suited for growing in Singapore’s tropical, hot and humid climate. Unlike the English ivy which tends to trail over a pot, Senecio macroglossus exhibits a predominant climbing habit by twining its slender stems around supports. When climbing up or sprawling on an area that kept moist most of the time, the stems may produce roots at the nodes along a stem.

In my workplace, we got some Senecio macroglossus plants thriving in a rather shady corner in the nursery. Various internet sources and houseplant books indicated that this vine can be adapted to grow in sunnier eareas. To grow Senecio macroglossus, it is recommended to grow it in a neutral to slightly alkaline, fertile, loamy soil that is well-draining.

To feed it, it is recommended to apply some pellets of slow-release fertiliser that is supplemented with liquid foliar feeding.  In general, Senecio macroglossus is relatively pest- and disease-free. Aphids and mealy bugs may attack developing flower buds or young growing tips. Over-watering or constantly wet root zone can cause the vine to rot.

Senecio macroglossus can be propagated by stem-cuttings or seed. Stem tips root easily when planted in a well-draining soil mix. Seeds are hard to obtain as they are not available commercially. In the house, this vine can be displayed as a hanging basket subject. Due to its climbing habit, it can be trained to scale up a trellis. It is also recommended to be used as a ground cover but I wonder can it survive the heavy tropical rains in Singapore?

For the longest time, I was wondering what caused the young new growth of my peppermint plants to become distorted. The young leaves were consistently smaller, appeared to bunch together and leaf undersides were bronzed.

At first, I thought the culprit was either thrips or spider mites. I cut away most of the aerial growth and then sprayed either white summer oil or neem extract on my plants. Subsequent new growth still exhibited the same symptoms. I took a closer look at the distorted leaves and found no thrips or spidermites. I searched the herb growing books that I have in my possession as well as some websites on the internet but found no leads.

After some extensive searching using various keywords, I finally pounced on a website that offered an answer to what I have experiencing with my mint plants. The page entitled “Information on Peppermint – Verticillium Wilt” was found in an online resource called “An Online Guide to Plant Disease Control” that is maintained by the Oregon State University.

In that particular page, the symptoms of verticillium wilt were described as follows:

“First, upper leaves twist and curl. Leaves are bunched at the top of the plant. Infected plants are stunted yellowish to red or bronze. Lower leaves die first, then the aboveground part of the plant. With flowering or other stresses, stems or plants may die too rapidly for these symptoms to be observed.”

The page also shared that this fungal disease is soilborne and once established in soil is almost impossible to eradicate due to microsclerotia, which germinate and infect roots. The fungus grows throughout the vascular system and up into mint stems. After diseased plant parts die, microsclerotia form and remain several years in soil.

The disease is revealed on various other web resources to be transmitted during cultivation, transplanting, or by flowing water and soil moisture. Verticillium wilt can be transmitted from plant to plant by grafting and budding.

The solutions offered appeared to be either limited in terms of their efficacy or difficult to implement for an average gardener. I guess for now, I have to dump the diseased plants and infected soil. I will then use disease-free plant materials for propagation and sterilised soil mix to grow them from now on. There will be a need to dis-infect all cutting tools to prevent the spread as well.

Gardeners who grow food and medicinal plants would prefer not to use any harmful synthetic chemicals to control or cure pests and disease problems in their gardens. I recently came across an online resource that most organic gardeners and edible plant growers would be looking for.

The website termed “OISAT” (Online Information Service for Non-Chemical Pest Management in the Tropics) contains information on non-chemical pest management that can be used to minimise pest damage in a safe, effective and ecologically sound way in the tropics.

OISAT shares information on various non-chemical pest management practices which include preventive measures such as crop design and layout, cultural practices, management of natural enemies, and mechanical methods, as well as, curative measures such as pest-controlling plants, physical methods, the use of other substances such as soap, and other methods which include a diversity of types of methods not forming a particular category.

The term “non-chemical” for practices and products which exclude synthetic chemical pesticides and genetically altered substances. Non-chemical products, as they are used in the OISAT context, may be processed on the farm but also manufactured commercially. The non-chemical commercial products, which are not excluded, are biopesticides, which are permitted in organic agriculture.

Information is cateogrised into three main sections. Under the tab “Crops”, one would be able to find non-chemical pest management practices according to the cropping season of the major crops, indicating key pests for each growth stage and plant part.

To find methods specific to a particular pest or disease, one can click on the “Pest” tab. One can expect to see illustrations or photographs of a particular pest and disease and the recommended non-chemical management methods.

The actions of some non-chemical management methods cover a wide spectrum of pests or diseases, click the tab labelled “Control methods” to find out what other pests and diseases a particular method also help to treat or eradicate.

OISAT is brought to netizens by PAN (Pesticide Action Network). PAN is a network of over 600 participating nongovernmental organizations, institutions and individuals in over 90 countries working to replace the use of hazardous pesticides with ecologically sound and socially just alternatives. PAN was founded in 1982 and has five independent, collaborating Regional Centers that implement its projects and campaigns.

Click on the following URL to access OISAT:

http://oisat.org/

Argyreia nervosa, referred to via a range of common names including elephant climber, elephant creeper, elephant vine and silver morning glory, is a member of the Convolvulaceae (morning glory) family. Native to India and Burma, it was once a popular landscaping candidate in Singapore.

This perennial vine is particularly valued for its rapid growth rate and large size that it can grow into. The young shoots of this plant can extend several centimeters daily and the plant can grow up to 15 m long. Hence, Argyreia nervosa is often used to quickly cover up an area, such as a trellis or a long series of railings of a boardwalk. The visitor to the coolhouse at the National Orchid Garden in Singapore would have noticed this plant.

Argyreia nervosa is a distinctively furry plant. Its mature leaves are heart-shaped and have a light velvety feel. New growth of this vine is densely covered with fine, silver hairs that it appears as if they have been silver-plated. It is no wonder that it is a plant that is featured in HortPark’s (Singapore’s gardening hub) Silver Garden.

A friend shared with me that one can actually pick a young leaf still adorned with its silvery coat and press it between the pages of a thick book. The silver colour of the leaf will be preserved and can be laminated with a piece of cardboard to make a nice bookmark or greeting card.

Argyreia nervosa is reported to be very well adapted to a dry tropical climate such as areas near rivers and creeks but with a distinct wet and dry season. It is not naturally found in the wet, humid tropics. The silvery hairs found on the new growth is perhaps an adaptive mechanism that the plant has evolved to reduce water loss in such a climate.

This vine also produces pretty flowers at the vine tips. Hence it is advisable to not frequently cut back the growth of this plant if one desires to see its flowers. Each flower is shaped like a trumpet and resembles those produced by the common morning glory. When in flower, the blossoms add interest by punctuating the largely green background of leaves with lavender.

Besides ornamental value, Argyreia nervosa possesses medicinal properties. The roots of this flowering vine are traditionally used to treat rheumatism and arthritis whereas its leaves are applied to wounds and abscesses. Its seeds possess psychedelic effects.

Ruellia colorata is a spectacular flowering shrub that belongs to the Acanthaceae family and same genus of another flowering shrub, Ruellia brittoniana. It is native to Brazil and is well suited to growing in tropical Singapore. Not widely planted in Singapore at present, one can visit HortPark to take a look at this plant. A colony of this plant can be seen being grown just behind the black metal gates that lead to the gardening hub of Singapore. 

It is known via a range of common names which include colorama, wild petunia and lobster claw. For those of us who have seen its flowers, one would feel that the last common name - lobster claw – seems to fit the profile of this plant best.

This plant produces striking inflorescences terminally at the tip of each growing point. Each inflorescence is rather large in size and covered with large bracts that are orange-red in colour. Without the need to imagine, each inflorescence resembles a cooked lobster claw. 

Similar to the many other ornamental flowerings shrubs from the same family, the true flowers of this plant peek out from the back of each bract but are rather short-lived. The enduring beauty of inflorescences is due to the durability of the floral bracts. Ruellia colorata have leaves that are glossy and lanceoate in shape with a distinct sharp tip.

Despite its beautiful flowers, Ruellia colorata can be a difficult candidate to manage in a landscape. This plant is a scandent shrub and adopts a trailing growth habit. It sheds its lower leaves after some time which reveals an unsightly tangled mess of stems  at the base of the plant. Hence it is essential to prune back this plant after each flowering. This operation will encourage the plant to produce side shoots which will help to maintain a bushy growth habit.

Ruellia colorata is a candidate that can be planted in a semi-shaded location where it can receive some filtered sunshine. I read before on a website that it can be grown in shade outdoors! In HortPark, this shrub is grown under canopy of a taller tree and seems to perform relatively well and flowers.

Like many other woody flowering shrubs, Ruellia colorata should be planted in a well-draining location with fertile soil that is kept moist at all times. It benefits from having a layer of compost as mulch around the root zone which keeps the roots cool and moist, and decomposes to release nutrients over time.

Note that this plant does not tolerate waterlogged conditions. After pruning, fertilise plant with a balanced fertiliser to encourage vigorous growth of foliage. Once the foliage is well developed, add a dose of flowering fertilizer to promote the production of the lobster claws.

Lemon balm is a delightful herb that can be grown easily in Singapore. Here, we can buy very well-grown pots of this herb from most nurseries. There is little need to grow them from seeds or buy fresh herbs from the supermarket! For those of us who want a zest of lemon fragrance in our food or want a cup of lemon balm tea, all that needs to be done is to harvest a few leaves from the potted plants we grow at home.

Although a common herb, how many of us have seen the flowers of the lemon balm plant? Nurseries only stock young vigorous growing plants that are often not in flower. Our potted plants at home may often be showing new growth due to periodic harvesting of their foliage for culinary uses. For a long time, I have never seen the flowers of this lemon-scented herb in real life other than occasionally pictures of them in various herb books or websites.

For those of my friends who know me, I grow many Mediterranean herbs because I appreciate them for their growth form and scent. I don’t know how to use them in the kitchen. Due to this strange habit of mine, my pot of lemon balm plant had the luxury to grow at its own leisire and recently, it had decided to flower and put forth a flower spike. I thought to myself – luckily, I did not cut it back for propagation!

The flowers of the lemon balm are not something that we would go ‘wow’ when we see them. They are best described as inconspiciuous  because each flower is tiny, white in colour and produced in a whorl around the axil of the leaves. They are neither showy nor colourful.

It is no wonder why many herb gardeners advise others to trim away the flower stalk once we see our lemon balm plants are showing the first signs of flowering. The flowering process demands much energy from a plant and a flowering plant would concentrate all its resources in the reproduction process in the expense of its foliage. Because the lemon balm plant is mainly grown for its leaves, hence we would not want our plants to flower.

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.

My contribution to the second edition of the e-newsletter of the National Parks Board (NParks) was published recently. I wrote on the roselle plant (Hibiscus sabdariffa), which is quite a commonly encountered plant nowadays. It is so-called the famed ‘Ribena Plant’ in Singapore because its calyces are picked and boiled in water to yield a sourish drink that tastes like the real thing.

To read this article, click on the following link which will lead you to the page of the e-newsletter where the article is featured:

http://www.nparks.gov.sg/cms/nparksenewsletter/issue2/gardening/gardening-discoverroselleplant.html

There are several articles that focussed on Lifestyle and Conservation. Click on the following link to read further:

http://www.nparks.gov.sg/cms/nparksenewsletter/issue2/index.html

I have been rather busy with work lately that I have not been able to find time and gather enough inspiration to pen gardening feature articles for my Green Culture Singapore website. Here are some articles that I have managed to put together for your reading pleasure. Just click on the links to download the pdf files!

Green Culture Singapore Feature Articles (Apr 09)

In the month of April 09, I wrote an article on bird’s nest ferns, which are tropical ferns commonly grown as garden and indoor plants. In it, I described three common species and their cultivars that are often encountered. I also wrote an article that contains my thoughts after reading a book entitled ‘Jekka’s Complete Herb Book’. It is a fantastic publication that opened my eyes to Western culinary and medicinal herbs.

Getting to know Bird’s Nest Ferns

Bird’s nest fern is a common name given to several related species of ferns in the genus Asplenium and several species and their cultivars are commonly sold as foliage houseplants. They generally grow as a tight, nest-like clump with an unbranched rhizome where broad, undivided, green fronds emerge. Read this article written by Wilson to know more about the three different Asplenium species and their cultivars and how to cultivate them at home!

URL – http://www.greenculturesg.com/articles/may09/may09_gathering.pdf

 
Jekka’s Complete Herb Book

Eager to learn more about various Mediterranean and Western herbs? You may want to take a look at the work by Jekka McVicar, one of United Kingdom’s foremost authorities on herbs, published in association with the Royal Horticultural Society. Read this book review by Wilson to know more what the book has to offer as well as whether it is relevant to a herb grower who resides in the tropics.

URL – http://www.greenculturesg.com/articles/apr09/apr09_jekkaherbbook.pdf

Green Culture Singapore Feature Articles (May 09)

For the month of May 09, I was blessed to be able to get some help from two of my discussion forum members to help write an article each. Xuan Hong penned an article that focussed on the growing of slipper orchids which contains the information that were shared in his gardening talk on the same topic. Petunia Lee kindly wrote her thoughts after attending a recent members’ gathering for Green Culture Singapore members.

Learn to Grow Slipper Orchids

Slipper orchids produce attractive flowers with their characteristic pouch-like lips that resemble a lady’s slipper. Although these plants may be mistakened as pitcher plants by having a pouch, it is a common misconception that slipper orchids are carnivorous. Read this feature article written Lim Xuan Hong, one of Green Culture Singapore’s young orchid growers, where he clarifies this confusion and shares how one can grow these alluring orchids in the tropics. This article is a summary of the talk which he delivered on the same topic on 23 May 09 at HortPark.

URL – http://www.greenculturesg.com/articles/may09/may09_growslipperorchids.pdf

GCS Gathering on 23 May 09

Green Culture Singapore had its first gathering for Year 2009 on May, 23 at Varisty Park Condo’s Function Room. The gathering was a memorable one for many of us. Unlike previous gatherings, this one was initiated by two members, Green Baron and Ah Kee. Read this feature article written by Petunia Lee, one of our very active and talented forum members, where she shares her thoughts and insights.

URL – http://www.greenculturesg.com/articles/may09/may09_gathering.pdf