Sunday, 11 June 2017

Steppe Lively!


Blimey, it has been some time since I last published a hortic post here. I’ve been very busy working, studying and writing ‘stuff’ elsewhere!

Anyway, having had a nudge from a colleague recently, I managed to find a vacant and warm afternoon in which to visit the Dunnett-designed rooftop gardens at the Barbican centre in London.

Having had the challenge of replacing the somewhat out-dated plantings of the 1980’s, Nigel Dunnett (Professor at Sheffield University) and his team began planting the Beech Gardens back in March 2015.  

The original planting featured areas of lawn, bedding (Yikes!) and bold architectural plants such as Phormiums and Cordylines. These had rather outgrown the site, requiring heavy irrigation and brought many structural problems to the site also. Ageing design, over-mature plants and leaky irrigation prompted the City Corporation to have a radical rethink. 

The Barbican ‘complex’ is a funny ol' place. I’ve visited it many times over the years, mainly to see cultural events at the Barbican Arts Centre. Built during the 60’s & 70’s, it’s a rather mysterious maze; a monochromatic greyness with three imposing towers, guaranteed to get you lost within its long walkways and tall walls of brutal architecture.


Registered as a listed building (or buildings), no changes could be made to the design of the existing beds and borders. 
So, with multiple aims of creating a self-sustaining community of plantings, which would provide all-year-round interest and satisfy the needs of its residents, Dunnett set about creating an oasis of naturalistic plantings all sat within a tough and demanding environment.
 
Layers and layers of sumptuous plantings!
Of course, the site itself is an elevated one, open to all the elements, and with strong winds funnelled throughout its architecture. Soil depth is also an issue with some plants being anchored in little more than 35cm of soil. So, mindful of the lack of irrigation, soil depth and exposure to the elements, it was to the natural landscapes of the world’s steppes that Dunnett turned for guidance and inspiration.

Steppes occur around the globe, and are to be found in the rain shadows of mountainous regions: the foothills of the Rockies stand as a good example of a landscape that, in recent years, has provided many a contemporary garden with a variety of naturalistic-looking plants: Rudbeckias, Echinaceas and many ornamental grasses. 

Temperate Grasslands, North America, KS2 Geography
Oh give me a home, where the buffalo roam......!!


Steppes also provide plants with a pendulum-swing of extreme weather conditions – bitterly cold winters and boiling hot summers. Steppe plants need to be tough and resilient, able to withstand the feast and famine approach of a weather system of extremes. Very often these plants sit within very thin soils, fighting to hold on to both nutrients and moisture. Sounding more like the Barbican every minute!


Nigel Dunnett devised a 3-teired design solution to the Barbican plantings: the use of Steppe plantings for the driest, most exposed parts of the garden. A shrub-steppe idea, allowing for plants (trees & shrubs) to be used where deeper soils were available, and  some light woodland planting for the shadier areas of the garden. He also factored in layers of succession,  with both colour and form coming in waves throughout the year: as one herbaceous layer dies down, so does another level of material rise up to give a completely new feel and look.

As I say, I saw the gardens in early June, and they looked pretty darn spectacular to me! I saw zillions of Alliums, all flowering atop of their drumstick stems. I saw masses of Salvias and Sisyrinchiums in amongst countless self-sown silvery and white Lychnis.
 

The green bracts of the Euphorbias contrasted with the purple Allium heads and nestled among the many Blue Oat grasses - Helictotrichon sempervirens. There were the butterfly flowers of Gauras dancing around the heads of Libertias and many a yarrow blending effortlessly with the pin cushioned flowers of the Knautias – how very lovely!



Personally, and with my current study interests in mind, I find the entire subject of a Dunnett-designed landscape absolutely fascinating. Without doubt, they (the Sheffield School) are the latest incarnation of naturalistic garden design. They experiment and trial seed mixtures - as opposed to plants - in order to create beautiful and sustainable, layered and successional, perennial plantings, that require little in the way of maintenance.


As I say, it's not a subject I know a huge amount about, but I find the subject fascinating none-the-less. I also love witnessing, mainly from my arm chair, the evolution of our ever-increasing journey towards more naturalistic gardens.  





Anyway, I’m heading back to my study and my books now, so this might be my last post for a good while.

Meanwhile, thanks for reading… and if you do get a chance to get to the Barbican this summer, please do so. You won’t be disappointed.

All the very best. 

Marc

Le Jardinier!

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