Cool plants for hot gardens
Silver foliage and light effervescent flowers take the edge off summer’s glare, writes Neil Ross.
For all the bright colours of summer, it’s always the quiet corners of the garden tenderly stippled with greens and whites – the sparkle of sun and cool shadows of crimped ferns – which I return to and find the most beguiling.
At a walled garden last summer, as I passed through a gate onto the dark side, I happened to look back and was met with a wall draped in a frosting of climbers which were reaching out arms of privetscented powder-puffs.
Pileostegia is a fantastic evergreen climber and makes a nice change from the hard-to-beat star jasmine (Trachelospermum jasminoides).
In front, a large urn was planted with Hosta plantaginea, which has classy scented blooms like small bunches of lilies. In the heat of summer, all this lovely green foliage and white flower was as welcome as a dish of vanilla icecream on a hot day.
You could have a stab at this effect with other umbellifers such as Queen Anne’s Lace (Ammi majus), a tall summer annual, but you will have to plant a fleet and they are easiest raised in modules where you can sow them in twos or threes.
The biggest challenge with creating a summer snowstorm is that white, doled out too liberally, can take on the glare of car headlights – almost bleached out in strong sunshine. So if you want to add some cool milkiness, go easy on the big impact flowers such as ‘Annabelle’ hydrangeas and delphiniums, and tuck your frosting away into shaded corners where it can quietly pulsate and add much-needed illumination.
Imagine not a dinner room of mashed potato but instead, an English flower meadow in midsummer – all foaming with cow parsley and dandelion clocks – with seahorses of hogweed and meadowsweet rippling through swaying grasses. Meadowsweet (Filipendula vulgaris) would grow happily over here but classier still would be white thalictrums, though again you need to go for the effect wholeheartedly, throwing a truckload of plants into your patch.
Any white self-seeders are always to be made welcome such as Nicotiana alata with its evening scents or white cosmos (poached egg flowers but delicate foliage). I can’t seem to get rid of feverfew from my garden but I love the way it, too, puts itself about the place, settling into corners and looking perfectly at home just as real snow would. I have a little lime green euphorbia which has the same nomadic habit and when the two get together, the effect is as cooling but invigorating as a peppermint sundae.
Silver foliage is another good way to create a bit of frosty summer effervescence and is easy to find on various variegated plants, but it’s worth sniffing out some more unusual specimens which have strong leaf shapes as well as ghostliness. Just resist going overboard as white flowers are best seen against plenty of green and not confused with too many stripes and streaks.
I’m always looking for plants to repeat around a lawn or down alongside a path to provide muscular foliage punctuation, and Artemisia ‘Valerie Finnis’ is one of the few perennial plants with a silver leaf that makes itself noticed from a distance.
In a similar way, Jerusalem sage (Phlomis fruticosa) really shines but this is a big beast so you will need a large garden to use it to best effect. – NZ Gardener