Coastal pleasures on offer

This week, the spotlight has (literally) been on Castlepoint as the beachside community, and its many friends, has celebrated the centenary of the switching on of the lighthouse that graces its reef.

The lighthouse was showing its true colours at times over the weekend but, at other times, was lit with a variety of bright lights, surely making it a shipping hazard, as sailors, drawn by the display, could have been lured siren-like on to the rocks.

Castlepoint is a wonderful place for a variety of social reasons but, for gardeners and lovers of native plants and wildlife, there are other reasons to venture out eastwards, as the reef and the remarkable castellated hill that Captain Cook called Castle Rock are home to some interesting and garden-worthy plants.

Prime among these is the Castlepoint groundsel, Brachyglottis compacta.

There are many species of Brachyglottis in New Zealand, among them a cluster of yellow-flowering, evergreen shrubs of coastal habits, but there are also inland, and even mountain species, the best known of which is the rangiora, B. repanda.

Castlepoint's daisy is a bushy, evergreen flowering shrub of low growing habits - about a metre or so - and the only place it is found in the world is on the limestone cliffs at the beach. It has oval-shaped leaves about 2-4cm long which are green above and white below, with slightly toothed edges. The flowers are yellow and appear in summer.

As you would expect, this is a brilliant plant for dry places and will flourish through the worst Wairarapa droughts in hot sunny places, its golden flowers following by wispy white seedheads.

Wairarapa is also home to the similar, but subtly different, B. greyii, which is found in coastal areas to the south, from about Flat Point around to the mouth of the Orongorongo River. It has slightly greyer leaves, but retains the silvery down on the underside, and gives a greyer appearance than the Castlepoint species. It has an even better display of golden flowers, making this particular species popular overseas.

This is another great shrub that does well in hot sun, coping well with poor soils. We have struggled a bit with this plant as it is planted in rubbish soil, a piece of land previous owners filled with road scrapings.

The soil is heavy and wet in winter, and these plants are not keen on those conditions.

As you might expect, these species have been crossed, and they are the parents of several interesting hybrids including the popular Brachyglottis Sunshine, which is another hardy form with grey leaves and a super abundance of yellow flowers.

Overseas there is a variegated form of this plant but it is hard to see how it could be an improvement.

Otari Cloud is a similar hybrid and has heaps of bright golden flowers over grey foliage.

I suspect these plants have become muddled in the horticulture trade and buying any one of them might mean you end up with one of the others.

There is one form that is quite different - Brachyglottis Leith Gold is a Dunedin-raised form with a mix of the attributes of its parents, having large leaves that are similar in size to rangiora but having the colour and texture of B.greyii.

This interesting plant has a fairly open habit, again halfway between its parents, and it carries panicles of small yellow flowers, intermediate in size between the tiny flowers of rangiora, and the larger flowers of the Wairarapa species.

To get the biggest leaves, it is necessary to grow this in some shade, but it will cope with full sun otherwise.

Among the other interesting plants at Castlepoint is a creeping Pimelia, largely found among the sand dunes at the foot of the reef, alongside various grasses and tussocks.

I have always known it as the sand daphne, P. arenaria, but I understand the botanists are now saying it is an unknown species, related to the aforementioned.

Either way, it is a pretty little thing, with small grey leaves, not unlike some of the spreading hebes, with pointed foliage and racemes of white flowers.

There are more than 30 species of Pimelia in New Zealand, but they are not usually found in garden centres, and you are more likely to stumble upon some of the pink-flowered Australian hybrids.

If you are looking for a small groundcover, you could do worse than go for our native hybrid Silver Ghost, which is an attractive silvery groundcover. The flower heads are much larger than any other groundcover Pimelia and the plant will grow to about 30cm.

It is a great plant for walls or the edge of the border, but also looks great cascading down the side of a large terracotta pot. I should think it would look great with the chocolate-coloured succulents that seem to be all the rage at the moment too.

During the week, I have had butterflies on my mind. It has been a good year for monarchs and I nearly tripped over one early one morning while I was running home from the gym. It was on the footpath and I only just saw it before my big feet would have crushed it.

As I stumbled around to avoid it, it blithely took off, flying between my flailing legs, away to safety.

There is a connection with our story - there is special Castlepoint moth too, an unnamed species of Notoreas found only at the beach, a pretty little moth with black-and-white-striped wings, coloured with burnt orange.

The moth features on the front cover of the picture book published to coincide with the lighthouse's centenary - A Beam of Bright Light, written by local writer Ali Foster and illustrated by the equally local artist Viv Walker.