15 October 2017

Favourite Nectaring Plants #14

Butterflies' Favourite Nectaring Plants #14
The Golden Dewdrop (Duranta erecta)

A male Plain Tiger feeding on the attractive purple flowers of the Golden Dewdrop

Our fourteenth butterfly nectaring plant in this series is an attractive flowering bush, the Golden Dewdrop (Duranta erecta). This plant, with its lush green leaves, purple flowers and golden yellow fruits, is often cultivated in many parks and gardens in Singapore as hedge or as a colourful accent to the horticultural palette in landscape design.

The Golden Dewdrop is certainly not considered a "weed" or a wildflower, unlike the last couple of plants featured in our Butterflies' Favourite Nectaring plants series of articles. Often preferred by gardeners for its showy terminal clusters of purple flowers - known as racemes, the Golden Dewdrop is also unique in that its clusters of yellow globular fruits are also featured as part of the aesthetic value of the plant.

A flowering Golden Dewdrop bush at an urban garden

The genus name of this plant is in honour of Castore Durante da Gualdo, a fifteenth-century physician, botanist and poet of the Italian Renaissance. Amongst Castore Durante's major botanical works were the Herbario Nuovo, published in 1585, which is a description of medicinal plants from Europe and the Indies (East and West) and Il Tesoro della Sanità, published in 1586, is a collection of folk-medicine remedies for the family, with practical rules for hygiene and dietary suggestions.

The specific epithet erecta means "upright" in Latin. The plant is also known as D. repens, from the Latin for "creeping". The latter name was originally used to identify smaller-leaved varieties of the species. In some literature, the Golden Dewdrop is also called D. plumieri. However, in contemporary botanical references, the name Duranta erecta has been the most widely accepted taxonomic name for this plant.

It is considered an exotic plant in Singapore, but is common and found in many public and private gardens. Interestingly, the Golden Dewdrop is registered as an invasive weed by many councils of Australia. It is considered a fast growing weed that is spread by birds from domestic areas to natural reserves. It was introduced and marketed as a hedge plant by commercial nurseries in Australia. Many people now fight to keep this thorny pest under control. It is highly ranked in the most invasive weeds in Australia.

Plant Biodata:
Family: Verbenaceae
Synonyms:Duranta repens, D. plumieri
Country/Region of Origin: Tropical America
English Common Names: Golden Dew-Drop, Lilac-flowered Golden Dewdrop, Pigeon Berry, Sky Flower, Brazilian Sky Flower
Other Local Names: Kachang Puteh, 金露花, 假连翘, 小本苦林盘

The Golden Dewdrop is a sprawling evergreen shrub and can even grow into a small tree of up to 6 m tall and can spread to an equal width. The shrub is usually well-leafed and used as boundary hedges or even for topiary in themed gardens. A mature plant has thick woody stems growing erect from the ground but new leaves grow prolifically and spreads rapidly. There are a wide variety of cultivars available, including 'alba', 'aurea', 'Aussie Gold', 'Gold Mound', 'Geisha Girl', 'sapphire showers', and 'variegata'.

The serrated-edged mature leaves of the Golden Dewdrop

The leaves are light green, elliptic to ovate, opposite with serrate or entire leave margins, and grow up to 7.5 cm long and 3.5 cm broad, with a 1.5 cm petiole. The leaves are soft when immature, but becomes a darker shade of green with thicker lamina when mature. Foliar venation is net-veined and each leaf ends in a sharp tip.

Axillary thorns along the stems.  Danger! Keep away from these sharp needle-like thorns!

Mature specimens possess axillary thorns, which are often absent on younger specimens. These thin, needle-like thorns are particularly sharp, and a photographer who is unaware of this "vicious" weapon on the plant, can suffer some particularly painful encounters. It should also be highlighted that the leaves of the plant is toxic, and combined with the thorns, it is best to be cautious around this plant.

Flower buds and flowers of the Golden Dewdrop

The bisexual flowers are light-blue or lavender, produced in tight clusters located on terminal and axillary stems referred to as racemes. The flowers bloom almost all year long. The plant grows best in full sun, where it blooms abundantly, but also tolerates semi-shaded locations. It should be pruned regularly to encourage new growth.

Fruit cluster of the Golden Dewdrop

The fruit of the Golden Dewdrop is a small globose yellow or orange berry, up to 11 mm in diameter and containing several seeds. These berries of the plant contains toxins, and are confirmed to have killed children, dogs and cats. However, it appears that some birds eat the fruit without ill effects, and indeed the seeds are dispersed by birds.

The golden yellow fruit of the Golden Dewdrop which probably gave its common name to the plant.  Pretty, but poisonous!

The berries may look pretty and almost delicious, but they are certainly to be avoided. Phytochemical analysis of fruits yielded alkaloids, glycoside, saponins, and tannins and poisoning is consistent with alkaloid-type reactions. When the fruits ripen, they turn black and shriveled. The seeds are contained within the fruit and are usually dispersed by birds that ingest them.

A selection of Swallowtails feeding on the flowers of the Golden Dewdrop

Now we move over to our butterflies. The Golden Dewdrop is a reasonably attractive butterfly nectaring plant, particularly in the urban parks and gardens. When the purple flowers are in full bloom, and where the garden is butterfly-friendly, many species are usually attracted to the flowers to feed. The larger Papilionidae love the flowers, and amongst the urban dwellers, we have seen the Common Mormon, Common Rose, Lime Butterfly, Common Mime and even the speedy Common Bluebottle feeding on the Golden Dewdrop flowers.

Some Pieridae butterfly species that like the Golden Dewdrop flowers

The Pieridaes also like the flowers for nectar, and the fast flyers amongst the Emigrants are often seen stopping to feed on the purple flowers. Striped Albatross is also a frequent visitor - both males and females, and the ubiquitous Common Grass Yellow. The high-flying Painted Jezebel drops down from its aerial acrobatics to refuel at the Golden Dewdrop flowers.

Many species of Crows and Tigers are attracted to the flowers of the Golden Dewdrop

The large Crows and Tigers are regularly seen feeding on the Golden Dewdrop flowers. Amongst those city residents seen are the Plain and Common Tigers, Dark and Blue Glassy Tigers and even the odd King Crow and Striped Blue Crow. Up north in Malaysia, the Dark Blue Tiger and Yellow Glassy Tiger (both of which are recorded as seasonal migrants in Singapore) have also been observed at the purple flowers of this plant.

Some Nymphalid butterflies that love the purple flowers of the Golden Dewdrop

The urbanite Nymphalidaes also take to the flowers of the Golden Dewdrop, and amongst them, we have observed the Tawny Coster, Blue/Peacock/Chocolate Pansy and Leopard at the flowers of this plant.

Amongst the Lycaenidae, I have only seen the Grass Blues stopping to feed at the Golden Dewdrop flowers, although it is a mystery why more urban species like the Common Tit, Peacock Royal and Cycad Blue, all of which have been seen flying in the vicinity of the plant, do not quite prefer the flowers as a nectaring source. Perhaps other observers who have photograph these Lycaenidae feeding on the purple flowers can share your encounters here.

Small skippers that feed on the flowers of the Golden Dewdrop

Finally, amongst the skippers found in our local parks and gardens, the most common species found at the purple flowers of the Golden Dewdrop is the Small Branded Swift. Other species observed feeding are the Lesser Dart, Palm Bob and one or two of the Awls.

So the next time you are out enjoying yourself at a community garden or a butterfly garden where the Golden Dewdrop is cultivated, do keep a keen eye on the pretty purple flowers of this plant and watch out for the butterflies that stop and feed at this favourite nectaring source.

Text by Khew SK : Photos by Chng CK, Foo JL, Huang CJ, Khew SK, Lee KH, Loke PF and Cindy Yeo.

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