New perennials and eco meadows for New Zealand

 

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Pic 1: Piet Oudolf’s planting at Scampston Hall Gardens, UK. (photo Nick Robinson)

 

Europe and North America are ‘ablaze’ with a wave of colourful, pollinator friendly perennial planting. The work of designers like Piet Oudolf, Tom Stuart Smith, Sarah Price, James Hitchmough and Nigel Dunnet has brought big scale planting with herbaceous perennials into two very important areas: the low maintenance landscape and the wildlife landscape.

 

It’s true: perennials are no longer to be associated with tedious staking and dead heading, annual lifting and dividing, manuring, and constant weeding. And yes, these stunning visual feasts are also a paradise for pollinators and other desirable wildlife. Perennial planting, in diverse colourful meadows and masses, now embraces natural form and seasonal cycles of growth and decay with seed heads and winter appearance very much part of the attraction.

 

Dutch plantsman Piet Oudolf became very successful thanks to his bold and unusual use of colour and winter effects. He started his career as a plant nurseryman, and his arrangement of plants echoes the intensity and boldness of plants laid out in nursery stock beds – large sweeps of texture and colour. His clumps and drifts of plants typically include robust perennials plus the careful use of grasses to counterpoint the vibrant flower colours and sculptural forms. Oudolf helped to popularize a new range of robust herbaceous plants and grasses that offered these qualities.

 

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Pic 2: Piet Oudolf’s planting drifts displaying his characteristic colours at Trentham Gardens, UK. (photo Nick Robinson)

 

But new perennial design in not just about which fashionable plants to use – what marks it out it is knowing the ecology that lies behind the horticulture – what naturally grows well with what: how to create lasting, balanced combinations or, as I prefer to call them, plant ensembles. These are also designed to be rich garden habitat, attractive to wildlife, particularly pollinating insects.

 

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Pic 3: James Hitchmough’s layered meadow mixture at Oxford Botalical Garden, UK. (photo Nick Robinson)

 

Recent developments have focused on ecologically based mixes of perennials by James Hitchmough and, in the case of Nigel Dunnett’s work – also annuals, both forming a meadow type planting. These mixtures are designed to perform through much of the year with interest refreshed as each new layer of foliage and flower emerges through the previous one. As gardener Thomas Rainer remarked:

 

“I began to think about plant composition differently. Before, I always understood one plant as inhabiting one place. But this new succession approach meant that multiple plants can inhabit the same space; they just emerge at different times. Some plants last, while others disappear entirely.”   

 

For me, this seasonal emergence and layering is the key to getting the most value from planting. Even in the northern parts of New Zealand where the seasons are less marked there is a vibrant sequence of flower, foliage and fruit colour through the year. This can be artfully employed in planting design – winter bulbs like scented Narcissus, South African spring bulbs, summer emergents followed by autumn flowers like asters some of which, such as red hot pokers – Kniphofia, flower well into winter. With care, all these can dwell in the same patch of ground, the foliage and flowers on one disappearing or reducing as those of the next emerge.

 

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Pic 4: An ensemble of summer perennials by Nick Robinson at Pakuranga, Auckland. Agapanthus inapertus, Phlomis russeliana, Libertia cranwelliae, Dietes bicolor and Rudbeckia fulgida (photo Nick Robinson)

 

One successful and simple example of this which I have used successfully on a number of occasions is the combination of bugle – Ajuga ‘Jungle Beauty’ for foliage at ground level and spring flower, merging (non-invasive) Agapanthus and Liriope for summer flower, and kaffir lily – Schizostylis coccinea (now called Hesperantha coccinea) for autumn and winter colour. These four species grow very happily together, occupying complimentary niches in space and time – try it!.

 

This kind of plant knowledge takes a while to acquire but leads to very satisfying and easy to maintain results because there is so little opportunity for weeds to get established. It means we can use perennials with confidence over larger areas (the diversity is in the mix and the seasonal succession) and we can get multiple values from small bits of garden in small urban spaces.

 

 

 

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Does natural = native? Does native = natural?

We live in a biodiversity hotspot (to find out more about what make this the case see the Conservation International website and especiallyhere. What makes us so important to global biodiversity is of course the range of native flora and fauna found nowhere else, and the fact that this unique New Zealand plant and animal life is at risk from loss of the habitats and damage to those that survive.

So we need to take great care of our special plants and animals, partly by protecting the places where they grow. But gardens and gardeners are also a valuable part of that conservation effort: many of our rarer plants are now common in gardens and public plantings. The three kings vine is probably the rarest plant in the wild in the world – only one plant has ever been discovered in the wild, growing on one of the Three Kings islands, but this species is now a common climber on fences and trellises in gardens. We still need to protect it in the would but it is important to know that at least the plant’s genes are safe in the gardens of New Zealand. Another example is the blue shore spurge, Euphorbia glauca – less immediately endangered but still in need of conservation effort. This is also popular in gardens, not least because of its distinctive foliage qualities and colour. The photo below is a stunning example of how combining this plant with other striking blue foliage specimens brings out the very best in its aesthetic colour and textural qualities.

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Photo 1: The rare native Euphorbia glauca combines superbly in a colour and texture inspired assemblage including Agave attenuata, Crassula ovata (Jade plant), Yucca species and others.

This is a classic example of the effective horticultural use of our native plants in combination with popular exotic garden and landscape species and varieties. Although it may look rather different in visual character, the next photo also shows a horticultural use of natives. This is a lovely bit of planting at Fern Glen Garden in Birkenhead, Auckland, a native plant collection. This composition does not include any exotic species but, with its careful arrangement of species from different habitats it is, in that way, just as artificial as the Euphorbia, Agave and Crassula.

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Photo 2: Planting at Fern Glen Garden: alpine hebe species, the threatened forest grass Anementele lessoniana, Olearia and the swamp loving Phormium tenax make a well composed assemblage. This is good for plant conservation – but is it a “natural” association?.

This crafted planting helps to conserve the gossamer grass – another threatened New Zealand plant but cannot be said to be ‘natural’ because it is artfully contrived and because these plants would be very unlikely to be found together in ‘the wild’. So is it really so different to the use of natives in gardens along with exotics?

This answers the first part of my title question – native does not, necessarily, = natural. Now for the second: can we be natural without being native? You might be wondering what exactly is the point of these distinctions – perhaps they are a bit academic but the idea I want to convey is that when we are looking for naturalness and wildlife habitat in urban landscape and gardens the answer does not always come in the shape of New Zealand natives. In fact I am going to argue that one of the best way to use them is to mix natives and exotics in a new naturalistic way to create a garden buzzing with insects and melodious with birdsong. Is this heresy? Tell me what you think.

We know how the tuis and other nectar feeding birds love many of the exotic trees like silk oak (Grevillea robusta), banksias and gums like the winter flowering Eucalyptus leucoxylon ‘Rosea’ Exotics, even weeds, can actually be valuable for wildlife too, especially the bees and other pollinating insects that are so essential for our gardens and food production. Bees are currently suffering alarming decline worldwide, including New Zealand and need as much pesticide free food plants as we can provide. Bees and other pollinators love nectar and pollen-rich flowering trees such the red gum Eucalyptus ficifolia, the willows in early spring, and even Hakeas, as well as many herbaceous flowers including echinaceas, asters, cosmos, foxgloves, persicarias and so planting these provides much needed food and shelter for this valuable wildlife.

Gardens full of exotic flowers can be so rich in biodiversity that a Sheffield University research project in the UK found that urban gardens could host a greater diversity of plant and animal species by area than some national nature reserves.

Perhaps surprisingly, these kinds of plants can perhaps be successfully combined with NZ natives as long as we are careful to match growth habits and aesthetic character. A recent garden in Te Atatua, Auckland by Philip Smith of O2 landscapes and another in Westmere both illustrate an innovative approach to combining rare natives with exotic plants, for colour interest and habitat value.

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Photo 3 : An Auckland garden by Philip Smith of O2 landscapes. This planting at the top of a limestone wall includes unusual natives such as Melicytus obovatus, Melicope simplex and Hibiscus richardsonii plus the deep maroon flowered South African Pelargonium sidoides and white-flowered form of Tulbaghia fragrans,

This Westemere garden is a lovely example of restrained design using refined plants but the more exuberant exotics can also be successful in very natural looking plantings. Consider figure 4: an apparently random collection of weedy wild flowers – mostly, but not entirely, exotic which have formed their own meadow-like pant community in the front garden of an Auckland garden. And indeed ventured out to replace the typical close-mown and spray-edged berm with a bio-diverse, colourful very low maintenance paradise for pollinators – It was a-buzz with bees and other insects when I took these photos. These plants are vigorous and ecologically well balanced, so very little cutting back or dividing is needed and a few weeds do not detract from its beauty. Could more of this type of planting be an alternative to hectares of mown grass and hectares of woodchip? I think so.

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Photo 4: A semi spontaneous, naturalistic meadow of perennials plus a few shrubs and trees. This includes asters, cannas, feverfew, cosmos, shasta daisy, stachys and a num

ber of other daisy family perennials. This occupies not only the front section but also the road berm and offers a great delight to all passers-by.

I will take a closer look at ways of creating flower-rich lawns and diverse urban grassland in a future article. Lawns full of bee friendly and beautiful flowers rae very suitable for our climate and ecosystems.

 

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Ecological design models for New Zealand urban areas

I think there is a  need to move ecological design in NZ beyond the twin poles of revegetation on the one hand and garden design with natives on the other. I have been thinking about how to do this and, during my ‘sabbatical’ at University of Sheffield, saw how effective a tool was the modelling of ecological design on wild communities but without the automatic adherence to the ‘indigenous’ plant menu.

To do ecological design in urban areas we need to look for vegetation communities in the wild of New Zealand that are adapted to similar climate, microclimate and ground conditions to those found in the design site. What makes it more interesting and, in fact, more achievable is when those conditions are extreme – drylands, wetlands, nutrient poor lands, eg gumlands etc.

Gumlands bracken and sedges - the basis of a design assembly for impoverished soils. (click to enlarge)

Gumland ferns and sedges and shrubs – could be the basis of a design assembly for impoverished soils. (click to enlarge)

We are more familiar with the various wetland conditions found in many urban stormwater management systems and how these can be used to develop diverse wetland communities. Much urban landscape exists in close proximity to hard materials – concrete, asphalt, brick, etc.- Rather than remove all this and replace with topsoil at great expense can we use the pioneer vegetation of locations like Rangitoto lava beds? In the unique and distinctive Rangitoto vegetation can we see inspiration for city landscape

Rangitoto colonising vegetation. in the most extreme conditions of drought  and salt water.

Rangitoto colonising vegetation in the most extreme conditions of drought exposure and salt water.

Ecological design is about designing with plant communities rather than plant species. The basic unit of design is the community or ecosystem (the community plus its physical environment). It is the way we put these together that can create the diversity  and intensity of vegetation and habitat that we need and enjoy in urban areas.

complex layering in established coastal forest creates attractive and intense detail.

complex layering in established coastal forest creates attractive and intense detail. (click to enlarge)

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