Edinburgh's spicy glasshouses

From the gloom of a wet Edinburgh autumn dawn, Louise opened a door into an unsuspected world. Above rain thundered on glass roofs, below a humid, steamy and scented jungle stretched before me, thicketed with unfamiliar leaves, escaping roots, lurid flowers and huge glowing seed heads.
 
Pushing away the dripping foliage that crowded us on every side, Louise Louise and HelenGalloway, Glasshouse Supervisor welcomed me to the Royal Botanical Gardens’ National Collections of Zingiberaceae.
 
Edinburgh’s stately botanical gardens house 7 National Collections, largely originating in tropical and subtropic forests – Aeschynanthus (climbers from the subtropics), Boesenbergia, Vireya rhododendrons, and members of the Zingiberaceae family - Curcuma (turmeric), Globba, Kaempferia, and Zingiber (culinary ginger). The Botanic Gardens also contain other spectacular members of the Zingiberaceae which are not yet in National Collections – the Alpinia (Ginger lily) and Costus. Examples of all of these are displayed in naturalistic plantings in the big glasshouses open to the public. In the longer established houses the visual effect is overwhelming – lush jungles canopied with flowering climbers, pillared with tree trunks smothered in epiphytic shrubs, and thickly carpeted with brilliantly patterned foliage from which luminous flowers and seed heads emerge. Flowers and moisture drop on your head, you find yourself checking your shoulders anxiously for exotic insects …
 
But beyond the sliding doors marked ‘No entry - Staff only’ is the private world of the scientific researchers. Here thousands of plants are not laid out for visual effect but to a more prosaic plan. The plants seem to fight the imposition of order on them – overflowing their benches and reaching for the glass ceiling; roots sneak out of pots across the graveled benches, throwing up new shoots whenever their keeper, Helen, turns her back. A species that seeds prolifically into its own and neighbouring plant pots has to be isolated in the midst of another genus, rather than benched with its own kind – Helen explains that this is so that any progeny can be easily spotted and removed before they cause confusion. Helen’s charges are propagated solely by vegetative means to ensure the genetic purity of the offspring.
 
Each pot is labeled with barcode, name, origin and other details – Louise Unidentified zingiberpoints out plants collected on trips to Indonesia and Vietnam and across Asia over the last decade including some she has found herself. Helen, in whose skilled hands these plants are nurtured, explains that many of the plants have not yet been fully identified – a Zingiber, yes – but which one?
 
Many arrive as dormant rhizomes, and Helen must wait months until they recover from the trauma of collection, storage and travel, before characteristic shoots and flowers emerge. She must guess what they will need in terms of growing medium, nourishment and water based on the observations of the person who collected the original. So one plant, which Louise discovered embedded in a rock face, was happily potted up in a tall, narrow rose pot to replicate the deep slits into which its rhizomes had grown – had Louise not seen for herself how the plant was growing, experience would have suggested that the rhizomes should have been laid on the surface of a standard pot.
 
Today researchers are increasingly using DNA for identification and classification of the Zingiberaceae but it is a slow and costly process. Some may be as yet unknown to botanists and already on the brink of extinction as their rain forest homes are bulldozed for palm oil plantations. With the loss of habitat goes the loss of folk knowledge about these plants – their uses for flavouring, foods and medicines. Louise points out the edible ginger Zingiber officinale, with the familiar ginger ‘root’ – in fact a rhizome growing above the ground (which finally explained to me the mystery of why supermarket ginger is earth-free!). No-one would grow Z. officinale for its ornamental value, but there are other more glamorous species.
 
Two hours fly past as Louise and Helen guide me round their charges and the rain slackens and the sun breaks through. I can’t wait to return to see the Vireyas in flower and … well there’s so much to see at every season of the year at Edinburgh’s extraordinary tropical core.

Images:
From top: Costas varzeatum
Louise and Helen 'behind the scenes'
Globba winitii
Curcuma aurantiaca
Unidentified Zingiber
Zingiber officinale - culinary ginger
All copyright Nicola Savage

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