Seaside gardening

Anyone who has tried to establish a garden on sandy soil knows the expense and despair involved, but there is another way and it will help the local environment at the same time.

“People with beach houses have it all – salt winds, sandy soils and prolonged dry spells. There’s a real need for people gardening in the coastal environment to be helped,”’ says Mark Dean, who in 2011 retired from the business he founded with wife Esme, Naturally Native, a wholesale nursery.

“This country has an incredible palette of native plants. Why don’t we use them?”

Naturally Native provided the plants for the top garden at the 2008 Auckland Flower Show, designed by Trish Waugh and Sue Peachey of The Landscape Design Company at Athenree.

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Moved by Tides. Photo: Sandra Simpson

‘Moved by Tides’ was devised as a border between wild plants and a garden planted in a dune system that used only native plants.

Mark, who is president of the Dunes Restoration Trust, says that correct gardening of dunes pays off both for sand stability and to create a sheltered space for more delicate plants.

He advises planting coastal species in the “calm time” of autumn so roots are well established by the summer, and to use successful native plants from the area to create shelter and frame the view.

Mark began growing Spinifex sericeus (dune tussock) in 1997 when he offered space at Naturally Native’s Whakatane nursery to a government-funded trial. “We learned you could grow it in root trainers if you found the right seed – but there are very few viable seeds in spinifex heads and you need both male and female.” Seed is collected in February.

“Marram, which is an introduced grass, tends to create steep dunes. The sand piles up behind it so you have dunes that are moving inland.

“Spinifex, which is native from North Cape to about Dunedin and also to parts of Australia, traps the sand between its runners, which grow down the beach, so builds dunes towards the sea.”

Mark says the value of spinifex was apparent after storms in June 2006 – a thick layer of sand was blown over the grass verge and road at Mount Maunganui’s Main Beach where there was no spinifex. But where there were trial plots in front of Domain Campground, there was little discernible sand movement.

Spinifex and pingao (Desmoschoenus spiralis) are the first plants to go on the foredune followed by, say, Carex testacea (sedge). In the dune’s hollow are plants like Muhlenbeckia complexa (pohuehue), flaxes and rushes with coprosmas and manuka on the back dune.

“If you plant a dune properly you drive the wind up and over,” Mark says, “and it’s in the lee that you can do what you like – I’ve seen one where the lady had the cottage garden she’d always wanted.’”

Euphorbia glauca is a native plant that has all but disappeared in the wild, “[it’s] only in places goats can’t get at it”, Mark says, but hopes it is poised to make a comeback as a garden plant.

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Euphorbia glauca. Photo: Sandra Simpson

“In the 1890s it was claimed to be the third most-common sand-binding plant in New Zealand. But the beaches were used for driving stock and what wasn’t grazed out was finished off by rabbits. There is a form on Motiti Island that they’re trying to reintroduce.”

He notes that where there was even a slight amount of vegetation or a small dune between the 2004 Boxing Day Asian tsunami and buildings, damage was reduced.
“There was a real lesson to be learned from that – dunes are a defence and need to be maintained.

“People have a tendency to throw their grass clippings into the dunes or their weeds and you end up with a real mess that does nothing to stabilise the dunes.

“We might as well garden them in an appropriate way rather then struggle with pansies. I believe Aotearoa should look like Aotearoa and not England or South Africa.”

Mark’s pick of plants for a coastal garden include the tropical-look puka (Meryta sinclairii), karo (Pittosporum crassifolium) with its red flowers, Cordyline (cabbage tree), houpara (Pseudopanax lessonii) which provides summer food for birds, toetoe, prostrate Coprosmas (acerosa has orange branches, acerosa Red Rocks red), Brachyglottis greyii (Cook Strait daisy), Hebe hulkeana (New Zealand lilac), divaricating Muehlenbeckia complexa (pohuehue) and Poor Knight’s lily (Xeronema callistemon).


Xeronema callistemon. Photo: Sandra Simpson

Mark was awarded the prestigious Loder Cup for his services to conservation in 2011. Read about that award here.

  • This article first appeared in the Bay of Plenty Times and appears here with  permission. It has been slightly edited.

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