Sunday, January 25, 2009


It is one of the quirks of history that our gardening ancestors learnt their craft in the cold lands of the Northern hemisphere. The plants they most valued were those they were most familiar with – the Rhododendrons, Camellias, and roses.
We have followed the tastes of our British founders, to a large degree, when it comes to the garden. I wonder how different our gardens would look if we came from a different gardening heritage.
Take our fascination with the Rhododendron. It is regarded by many gardeners as the ultimate tree or shrub. It is available in a wide range of colours, it is dependable, some varieties are a challenge to grow, and it is delightfully evergreen.
But if we inherited the gardening traditions of another, warmer clime, I wonder whether we might not be cherishing another plant that we tend to be a bit pretentious about – the wonderfully flamboyant tropical Hibiscus.
Among the many species and hybrids of this wide-spread genus, there must surely be the loveliest of all the summer flowering shrubs for the New Zealand garden, with amazing flowers held on tidy plants.
They are, of course, frost tender, and most varieties will need careful placement. In our inland towns they will need to be placed against a north-facing wall, preferably in full sun, and with well-drained soil. All varieties hate clay, and will not thrive at all in water-logged soils, so it pays to completely replace the soil if you are stuck with gardening on clay – or grow some of the smaller varieties in pots.
We have grown a couple of shrubby hibiscus for many years in containers. They are slightly neglected – they are never fed and seldom pruned – and I am sure we could do a let better if we spent a bit of time on them.
Firstly, we should be feeding them in spring/ early summer. Once established, Hibiscus are relatively hungry feeders, and will respond well to a good application of a general fertiliser. A slow-release form, designed for trees and shrubs, would be even better.
Hibiscus only flower on new wood (like roses, come to think of it) and a regeneration of branches each year is needed. Just prune back at the same time as you are pruning the roses in July/August, and they will respond with a flush of new growth that will bear flowers from December through to winter.
Hibiscus can cope with a very vigorous pruning. If they are starting to get a bit leggy and woody (they look very uninspiring when they do) just cut them back. Within a year they will have bounced back with a whole lot of new growth, and more crops of flowers.
Most varieties branch near to ground level and make attractively thick growth. If you have a mind to, they also can be trained to make wonderful espaliered shrubs.
A childhood neighbour grew a luscious pink Hibiscus against her chimney – it grew right up to the gutter of the house and threw large single flowers all summer long. I think the frost was probably training it, as I do not recall her ever trimming it.
The most common Hibiscus seen in New Zealand are the Fijian varieties. They are smaller growing, bushy shrubs, and are slightly hardier than their Hawaiian counterparts.
Perhaps the most common varieties are ‘Suva Queen’, with her double pink flowers, ‘Agnes Gault’, a single pink that was probably what my childhood neighbour grew, and ‘D J O’Brien’, semi-double tangerine.
Hawaii has a number of native species which have been crosses with the older forms to give a new race of plants. They are tenderer than the Fijian types, and need more sheltered growing conditions. This far south, they probably do best in a conservatory in all but the warmest sites.
‘Golden Belle’ has rich bright yellow flowers in abundance; ‘Hawaiian Sunset’ is cerise pink with yellow edges; and ‘Nathan Charles’ had large flowers of crimson red.
Some of the Hawaiian forms are not very vigorous on their own roots and thus need to be grafted.
The Fijian and Hawaiian varieties have been crossed and recrossed, and there are now literally hundreds of varieties around, many of them bred in New Zealand and Australia. It would pay to have

Monday, January 19, 2009

More time on the river

The Mangatainoka River

This weekend I journeyed north to Putara, to take the next steps along my river walk. I walked in to the headwaters of the Ruamahanga by going up the valley of the Mangatainoka (of ‘Tui’ beer fame) then crossing a ridge to Roaring Stag Hut.

Roaring Stag Hut

It was blowing real hard there, and the swingbridge was rocking as I gingerly crossed over it. The wind took my hat on the way. I managed to sneak up-river and downstream shots as I went over.

I jumped into the river bed there and rock-hopped another two hours down to just below Cleft Creek, the point I started my journey last February. On the way out, I used my still camera to take this video of myself crossing an un-named stream – reportedly the largest stream in the Tararuas without a name.


When our elder son spent time here over Christmas, his girlfriend insisted he show her around our garden. They are new gardeners, always difficult in flats, and they have concentrated their efforts on vegetables – but Ana was keen to see how much plant knowledge is absorbed by someone brought up in a nursery.
He did not do too badly, managing to name about half the flowers in the garden, and even surprised me by remembering the name of ‘Strawberry Parfait’ Dianthus. I assume it must have been the association with a dessert that kept it on his mind.
One of the Head Gardener’s favourite plants had them guessing though. She has a few clumps of a perennial growing in one of her gardens, with tall stems that are foaming with small mauve flowers at this time of the year.
The geneticist son had no idea what it was. His research scientist girlfriend thought it might be a different coloured form of “that filler you see in florists’ flowers”. She was thinking of Gypsophila of course, but the two plants have only a passing similarity to each other.
The plant that had them flummoxed was a Thalictrum, one of more than a hundred species in a large genus found over much of the Northern Hemisphere, with representatives also in tropical South America and southern Africa. They are essentially plants of damp or shady places (unlike the Gypsophilas). Their common name is “meadow rue”, but this is a little confusing as they are not closely related to the true rues, but are members of the vast Ranunculus family. The garden forms generally grow to a metre and a half.
They are dainty yet robust plants, usually with maidenhair fern-like foliage, and are ideally suited for a woodland garden, or a border with other tall perennials. The flowers are also valuable for picking, if you can bear to take them off the plants.
One I like is T. auilegiifolium – with divided leaves looking much like a Granny’s Bonnet, and heaps of tiny mauve flowers in early summer.
T. delavayi flowers later in the season, but also has a myriad of light mauve flowers. There is a stunning white form – more commonly found than the mauve one, and called with great imagination, ‘Album' – as well as an amazing form with double flowers. ‘Hewitt’s Double’ has masses of tiny little pom-pom like flowers. It is great for floral work.
A newer variety is quickly becoming a favourite among perennial gardeners – the intriguingly-named ‘Black Stockings’. In a way it is a stock standard Thalictrum – blue-green foliage, thousands of mauve flowers – but these flowers are held atop black stems. It makes a wonderful display in the garden.
There are a number of yellow flowers species. The most commonly found one in New Zealand is T. flavum. It has blue-green foliage and masses of light yellow flowers at about this time of the year.
The Thalictrums are generally no-fuss plants. They will do best in slightly heavy soils that retain moisture. They certainly look best in reasonable sized clumps, and are easily propagated. They look great when grown with other large perennials, especially those with large leaves

Sunday, January 11, 2009

Blue spires

For the last few weeks I have been writing about some members of the sage family – some of the many garden Salvias, both for the herb and ornamental gardens.
In my back garden I have a bit of a problem with a plant that is sometimes called a sage, the “Russian Sage”, Petrovskia atriplicifolia ‘Blue Spires’.
I love the effect this plant has in the garden, with its long spires of mauve-blue flowers springing from finely divided ferny-like silver branches.
This is a great, no-fuss plant; it is not fussy about soil conditions, does not worry about pH levels, and is also very drought tolerant. Mine grows in a semi-shaded spot among other perennials, but I suspect it would be best in full sun, along with most other silver-leaved plants.
Its growth habit is a problem though. It is a sprawling shrub, although usually grown as a perennial. I planted mine too close to the edge of the bed and it sprawls across the other plants near it and then lazes across the perimeter of the lawn.
This year I decided I had to do things better by it. I have always cut it back hard after flowering – and by hard, I mean very hard. At the end of the season it has branches about a metre and a half high, with a slightly larger spread, and I cut them almost right off, leaving stubs of about 20 cm over the winter. Russian Sage is very hardy and will not be damaged by such brutal action over the winter.
This encourages the plant to make good growth in the following spring – too good, in fact, as the soft growth flops all over the place later in summer. This year I remembered early enough in the season, and I nipped all the growths in the bud – tipping them when they were about 30 cm high. It has made an enormous difference. The plant has responded with better branched stems, and a better flowering effect at lower heights.
During the pruning, I found the foliage has a strong “herby” scent – reminiscent of wormwood or one of the other Artimesias – and not that pleasant! Still, I am sure it is now doing good work in the compost pile.
It would be fun to experiment with plantings to associate with this plant. I have it growing with some purple Delphiniums and a clump of the lovely Penstemon ‘Alice Hindley’, as per the photograph above, but it would look even better with pink coloured flowers I think. It also combines well with lavenders and other silver foliaged plants.

Sunday, January 04, 2009

The end of the holiday season

My all-too-brief season holiday is drawing to a close.
We have done the usual Kiwi Christmas things – eating too much in the warm weather, buying too much rubbish – but we have also taken part in some family rituals. One of those was our annual trip to Pukaha, Mount Bruce Wildlife Centre. This time we had two PhD students – our evolutionary geneticist son and his partner, a neurophysiologist – and one playwright, our younger son. The highlight was not the kaka feeding, from whence this photo comes, but the discovery of a tiny rifleman, high on the ridge overlooking the centre, at the ends of a new track.
Our other annual tradition is a beach visit, usually to Mataikona, a rugged beach east of here. The geneticist and I spent a lot of time searching in the rock pools for blue starfish, crabs, shrimps and his beloved snails. Also had some time to fly kites in the light wind.
Somehow the archive does not sound as appealing as flying a kite in the breeze…

Common sage and pineapples

I have already achieved the first of my New Year resolutions – I have planted out my plant of common sage, bought from the friendly herb seller at my local car boot sale. It is many years since I grew this sage, and I am not even sure I know why I have kept not it in the garden.
It can hardly be that it is hard to grow. Common sage, S. officinalis, is one of the easiest of all herbs. It is a small woody perennial, or sub-shrub perhaps, that needs only a moderately sunny place in the garden to succeed. It will flourish in most soils, but prefers slightly less fertility than most other plants. If grown in very rich soil it tends to grow too floppy and lax, and will not last so long. It will do best if restarted every four or five years, as it tends to get a bit woody. It is simplicity itself to grow from a summer cuttings, as it strikes with alacrity.
If you like an ornamental sort of herb garden, there are a number of forms with coloured leaves. The purple leafed variety is probably the best known, but there are also golden-leaved and variegated types around too. These are perfect if you are looking to plant a herb garden on a parterre pattern.
In the kitchen, common sage is probably most-often used in the preparation of poultry or pork stuffing, although it can also be used in sauces and drinks. It has a variety of medicinal uses too – in fact, a recent trial suggests it might be useful in the treatment of Alzheimer’s disease. As a matter of interest, the very name “Salvia” comes from a Latin word meaning “to heal,” and “sage” means wise.
I mentioned last week that I had planted a red flowered sage, a dwarf from of the once-ubiquitous ‘Bonfire’ salvias. Not everyone is keen on this plant, thinking it too much a blob of red pigment.

Most people would agree that another red flowered sage, the Pineapple Sage, S. rutilans, is a plant of a totally different kind. It is much larger for a start! If growing in suitable conditions it will happily grow to two metres in a season. It is a slightly frost tender perennial, but it will not matter if it gets slightly hit by cold over the winter as it will happily grow back to two metres the following summer.
And what a two metres it will grow to, with long stems of the most deliciously pineapple-scented leaves, topped with spikes of bright red flowers in summer. The flowers will be raided by bees, and children for that matter, all in search of the honey-like nectar stored in the long red tubes at the back of the flowers.
The leaves can be chopped up and used in salads – both green and the more fruity varieties – and can also be used as a garnish. The flowers are also edible, making a great splash in summer salads as well as giving a honey-sweet taste.