Even when successful, however, they came with a big “but” — British wildflower
flora is limited, and looks good for only a short period: May to June.
Additionally, many gardeners and other users of the seed mixes found that on
anything but the poorest soils, vigorous grasses took over, and the
proportion of flowers slumped heavily after a few years. Some of us in the
business began to look at other ways of creating large-scale,
low-maintenance plantings.
Wildflower meadows (when they work) are low-maintenance because the same
management operation (i.e. mowing) is applied to the whole thing. Individual
plants do not receive care, any more than the individual grasses in a lawn
would. Hitchmough had a dream: what if it were possible to create ornamental
plant combinations which could be treated in a similar fashion?
Imagine the creative possibilities: “I am interested in ‘calendar
vegetation’,” he says. “A lot of natural vegetation is visually very dull,
but if it looks good on a calendar then it is good. Real people haven’t been
on [ecology] courses.
I want an aesthetic that anyone on the street would think is attractive.”
It was in Australia that he began to make the connection between horticulture,
ecology and culture: “I was there for 10 years, doing research in Melbourne.
There is a very attractive, but almost extinct, West Australian habitat, a
grassland, which would look great in urban parks, and we had to work out how
to recreate that.”
At the University of Sheffield he turned his attention to a number of
wildflower communities that he believed could be used as a blueprint for the
creation of public urban plantings with the all-important “wow factor”. So
he began to look at central European meadows, moved on to North American
prairie and, most recently, South African montane grassland.
If the last one sounds exotic, it is where many traditional British garden
favourites hail from, such as montbretia (Crocosmia species), agapanthus,
dierama and red hot pokers (Kniphofia).
North American prairies are even more familiar to us — think “prairie” next
time you tend the border with its autumn-flowering asters, goldenrods
(Solidago species), rudbeckia, helianthus and helenium. It is these plant
communities that we see echoes of in the Olympic Park.
Seeds of an idea
How do you go about making an ornamental prairie or South African grassland?
The answer, Hitchmough insists, is seed. Think about the difference between
a wildflower meadow and a garden border. The former has hundreds of plants
per square metre, the latter, maybe nine or 10. The density of an
established meadow renders it relatively impervious to weeds: the openness
of the conventional border makes it hugely vulnerable.
For many of the Olympic Park plantings, Hitchmough has bought seed from
commercial sources. He then designed a mix, and sowed it into a substrate
that has to be as free of weed seeds as possible. The result is initial
plant densities of about 150 plants per square metre.
Unlike situations where plants are used, he explains, “seeding creates a more
genuine community where plant ecological preferences and competition between
plants decide where individuals grow.” In other words, the resulting
vegetation will be far more resilient than anything started off as plants.
The maintenance regime is designed to be as simple as possible. In
Hitchmough’s words, it should “do something uniformly across the whole site
that disadvantages the plants you don’t want and advantages those that you
do”. Mowing, familiar to anyone who has grown a wildflower meadow, is the
obvious example, but timing is critical. An August mow of an early-flowering
plant combination, for example, “checks the growth of taller competitive
dominants, lets light in and returns the system back to where it was in
spring”. Fire, too, can be a useful maintenance tool, with flame-gunning (a
weed-control technique familiar to organic growers) in February or March,
which kills “pesky annuals like cleavers and short-lived perennials such as
many willowherbs. It defoliates perennial weeds, so increasing the relative
competitiveness of the chosen species.”
I have tried a variant of this at home, and can testify to its simplicity and
effectiveness; most perennials will survive a light scorching — after all,
prairies and many other flower-rich habitats regularly experience flash
fires.
Flood prevention
Alongside Hitchmough’s work in the Olympic Park, his colleague Nigel Dunnett
has contributed colourful annual seed mixes and planted drainage “swales”. A
swale is a shallow depression designed to capture and hold water temporarily
after heavy rain, allowing it to soak into the ground, rather than run off
and cause flooding.
They are a key element in the new technology of what has become known as SUDS
(sustainable urban drainage systems). Swales at the Olympic Park are planted
mostly with wild-flower species that can survive occasional inundation but
which don’t actually need high moisture levels to flourish.
The third member of the team is garden designer and plantswoman Sarah Price,
whose role has been to work on the visual impact and spatial arrangement of
the plantings. “I’ve tried to weave together what James and Nigel do, using
bands of planting, making repetitions, merging their different planting
combinations,” she says. “I’ve used a lot of grasses and perennials with
good seed heads, as they have a long season.”
Examples are the grass Panicum virgatum, which has an impressive midsummer to
late-winter presence, and the perennial Veronicastrum virginicum with firmly
upright flower spikes that turn into statuesque seed heads and stand well
into the winter.
“I added many of my own palettes into the mix,” says Sarah. “Many are now
intermingled expanses of planting that look like meadow rather than strips.”
Sarah Price’s contribution is very much about providing structure and
coherence to what are extremely varied planting schemes, but doing so with a
light touch, so we appreciate it almost subliminally. Those who saw her
Daily Telegraph Chelsea Flower Show garden will get the idea.
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