The beauty of New Zealand broom has Margaret Barker entranced.
I had a conversation with a visitor to the garden. “I love your native broom,” said the visitor. “Me too,” I replied.
It’s such a gorgeous golden colour,” the visitor continued. “That’s not a native broom. Ours are pink,” I said.
“But we saw it… golden… all over the hills.” “That’s a noxious weed,” I added. “Oh no. It’s not a weed. It’s beautiful.” I put my head down and got on with it. Our visitor had been looking at the Scotch broom ( Cytisus scoparius) and, it is attractive in the landscape, but such a weed. It populates open areas on river flats, hillsides and verges of bush tracks. On warm days, seedpods explode, sending seeds many metres in every direction.
Our actual native brooms are rare.
Many are endangered in the wild. They comprise 23 species which range naturally from the north of the North Island to Stewart Island, from the mountains to the sea, but with a concentration on the drier, eastern South Island.
They range in form from creeping alpines to small trees, with only one climber, Carmichaelia kirkii.
Except for this climbing broom, carmichaelia grow in open, sunny, well-drained positions. They enjoy nutrient-poor soils because, like other members of fabaceae or pea family, they are able to fix their own nitrogen from the air through nodules on the roots. Most have pink- or purple-streaked flowers. A few are cream or creamy yellow.
New Zealand brooms are worth growing not just for these fleeting flowers, but for the textural value of their stems. As with most plants, attributes other than flowers are what you look at for most of the year. They are leafless and photosynthesise through their flattened stems which are decorative in themselves.
Marlborough pink broom ( Carmichaelia glabrescens) has a frenzy of pink blooms like candy floss in early summer.
I have planted it with a same-coloured clematis which wanders through the broom as its host. There are red roses and pink monarda nearby. These companion plants, the exotics, all enjoy good, rich, moistureretaining soil. The broom, on the other hand, requires sharply drained, nutrientpoor conditions. However it thrives up against the brick wall – perhaps the wall’s concrete foundations are to its liking. This confection is fleeting. The broom’s flowers don’t last but its weeping grey-green foliage, like a waterfall in arrested motion, adds value to the garden picture for all of the year.
Nationally endangered is our weeping tree broom, Carmichaelia stevensonii.
The specimen I planted at Larnach Castle at the back of the rock garden 40 years ago now makes a telling, structural statement. It is in light soil on sloping ground and in a rain shadow from the rain-bearing southerly winds.
Weeping tree broom can grow to 10m. I am looking forward to my one reaching these heights. It had better hurry up.
At the risk of being a bore, I’ll say it again: Why not intermingle our New Zealand native plants with exotics. I’m not talking here about revegetation – an important but separate issue – botanic gardens or national collections. I’m talking about your home garden looking attractive throughout the year.
Having a little native garden separate from the rest is apartheid. Plants are not going to catch something nasty if they mix with “foreigners” (plants from the rest of the world). Don’t be like the Ku Klux Klan; let’s integrate.