Sunday, September 24, 2006

Little Aussie battlers

One of the amazing things about the plant world is the sheer diversity it contains. The term ‘plant lover’ can cover an enormous range of interests.
I had thought my plant interests were fairly well defined, and that I was of an age when I was not going to fired by a sudden enthusiasm for a new class of plants. Then, just last summer, I found myself getting all excited about native orchids.
I have always like visiting orchid shows, although I have been resolute about not growing too many plants as I have enough trouble keeping my other enthusiasms under control. I like looking at the large-flowered cymbidiums and other forms, but it is the small-flowered species that get me.
Last summer I made a few forays into the ranges near home and found that the highlights of my journeys up into the alpine herb fields were the various orchids I found on the way up, and sometimes even on the way down!
When I go to an orchid show I make a beeline for the more unusual species on display.
I have a fascination with the Australian Dendrobiums, and it will be the display of these trans-Tasman beauties will be the first stand I visit. These are relatives of our native Winika cunninghamii, with delightful tiny flowers of typical orchid shape.
Our Australian cousins have a much bigger range of species and hybrids to choose from. The species that grabs me the most is the charming little rock orchid D. kingianum (more properly now called Thelychiton kingianus – really!). This grows wild from northern New South Wales up into Queensland, on rocks usually, as you would expect, but also sometimes on trees.
It is a small growing plant – maybe around 20 cm high – and has up to seven flowers per pseudobulb. These flowers are now available in a huge range of colours from white through to seep purple, although most are in the pink range.
Although these guys are not frost hardy they will stand quite cool conditions and are easily grown. If you can grow Cymbibiums you can grow these guys as well. Being dwarf they do not need large pots and will thrive in small plastic containers. At the shows there are always some huge clumps of these plants, in large pots, and the sight of hundreds of these flowers fluttering over the dwarf foliage is really something to savour.
D. speciosum (now also a Thelychiton) is a cousin of the rock orchid, and will readily form hybrids with it, but has a completely different form. It has tough leaves to about 40 cm high, topped by racemes of white to cream flowers, up to 120 flowers on each stem. The flowers are often finished of by purple markings on the labellum. It is a charming plant, with the large racemes drooping and displaying their flowers freely. The flowers are deliciously scented as well – very noticeable in an enclosed hall.
As you would expect, these two plants have been hybridised, and not just by keen orchid breeders either – they will cross in the wild when their growing areas overlap. The hybrid is known as D. delicatum, and is quite variable, but in the wild it is usually creamy coloured with purple markings on the labellum. The flowers are intermediate in size, and not carried with the abundance as D. speciosum, but are nonetheless still numerous. In cultivation these have been crossed with some of the darker forms of D. kingianum, with a bigger range of colours now available.
All of the above are quite straight forward to grow. Their main need is for absolute drainage – they will not grow in soil, or even in normal potting mix. In the wild they are lithophytes (they grow on rocks) and they need very sharp mix. The standard mix is composed of very coarse pine bark chips, or something similar.
During the growing season these plants will need watering most days but in the winter the watering can be held back to about once a week, or even less.

Tuesday, September 19, 2006

The best native climber

Reports have been coming in to me that the clematis is in flower on the Rimutaka Hill road. Friend after friend has been telling me that the trees are wreathed with the shining white flowers of Clematis paniculata, so this weekend I made a short trip out into the countryside to see whether the rumours are true.
Sure enough, the puawhananga are in flower and what a brilliant sight they make – surely the most brilliant of the native clematis, and also one of the most attractive of all native flowering plants.
There are hundreds of Clematis species scattered all over the temperate world, and of course, very many more hybrids and varieties. New Zealand has its share of these species and they include some very interesting plants, but the star is the puawhananga.
For many years this was hardly grown in gardens even though it was widely known. That may be due to simple sexual discrimination. Female and male flowers are borne on different plants. The male flowers are bigger and more attractive. In the past nurserymen have tended to offer plants that have been gathered from the wild and they take a long time to flower, then, when they do flower, the flowers have not been of the best quality.
Fortunately, nurserymen have learnt how to grow these beauties from cuttings (it is not easy from wild plants) and now we can have selected forms with known characteristics.
Probably the best of these is ‘Serenity,’ selected from wild plants growing in Canterbury and with flowers that can be over 110 mm wide.
To grow any Clematis paniculata properly you need to bear in mind the conditions it favours in the wild. To put it crudely, it needs its head in the sun and its bum in the shade.
In the wild, these plants grow in the litter at the bottom of the forest floor. They grow in friable humus-rich soil that is both cool and, usually at least, moist. In the garden, they need similar conditions, with perhaps a deep mulch on the soil. It pays to plant this near a tree or shrub that it can scramble up, although it will grow perfectly well along a fence. If grown along a fence do remember that it will need a cool root run and cannot cope with hot and dry soil conditions.
In the wild these plants grow with very long stems – in fact, it is sometimes very hard to track back from the flowers to see where the roots are. As they wander through the scrub, they tend to lose many leaves from the lower portions of the stems and this can be a problem in the garden if the plant is grown along a fence.
‘Serenity’ is, as you would expect from a southern plant, a hardy form of this species but a hybrid based on C. paniculata is even hardier. ‘Purity’ also originates from Canterbury and is perhaps one of the hardiest of all evergreen flowering climbers.
It flowers later than ‘Serenity’ – mid-October rather than mid-September- and its flowers are slightly tinted, indicative of its hybrid origin. The flowers have a distinct green colouring when first open, but fade to a pale cream if grown in light shade. In full sun the flowers turn pure white.
Again, this needs a deep cool root run to succeed well, but once established can cope with extensive periods of drought. However, it cannot cope with a dry and warm site so plant in under shrubs or trees for best display.
This is better than ‘Serenity’ for fence line plantings as it has long flowering stems that droop down, giving a dramatic floral display. If you decide to grow it along a fence line just bear in mind that this one loses foliage along the stem too, so it probably pays to cut it back by about a half after each flowering.

Wednesday, September 13, 2006

Blooming weepers

Over the past couple of years, I have been watching the progress of a couple of newly planted trees just down the road from our garden with great interest. The house was sold and new gardeners came. They kept much of the planting but they replanted a bed alongside their driveway, which had previously featured a row of standard ‘Iceberg’ roses in a box-lined bed. I like ‘Iceberg’, but I believe the row of standard white roses has been overdone in recent years, so I was intrigued to see what was going to replace the roses.
I would never have guessed what the new plants would be though – a couple of weeping peach trees.
Of all the various flowering fruit trees, the peaches are the least planted nowadays, although at one time they were very popular. My grandparents had a spectacular deep pink variety in their garden and it was a delight each spring. I think the best upright form of this tree, though, is the pure white double flowered ‘Iceberg.’ The white is intensely pure, as the name would suggest - it glistens.
From this tree came the weeping forms grown in New Zealand, ‘Cascade’ and ‘Pink Cascade’. ‘Cascade’ was the first weeping form to be released in New Zealand, and has the pure white flowers of ‘Iceberg’ – or at least, it mostly does. The plant is not stable as it throws pink flowers on some branches, so the effect is slightly softer. The growth form is gently weeping and when planted against a dark background, as the tree down the road is, the effect is very dramatic.
The light pink ‘Pink Cascade’ was selected from the white form, and has the same growth habits. The colour is fairly stable, although it does seem to throw the occasional rogue flower.
You do need to exercise a little care with flowering peaches in the garden on two counts. Firstly, they are rather prone to the same diseases that fruiting peaches are, in particular leaf curl. It probably pays to spray copper oxychloride at bud burst to keep this pest in check.
The other potential problem is silver leaf. This disease can attack large trees, usually when they have been heavily pruned. If an infection is noticed quickly enough, use of the natural remedy Trichopel will keep it at bay. Otherwise it is a case for the chainsaw I am afraid, as this disease will rapidly spread.

Tuesday, September 05, 2006

Wild freesias

We have been on holiday recently, in Rotorua and Gisborne. We were booked into a motel out at Wainui Beach, a couple of minutes past Gisborne city, and the beach proved too much of a temptation to us when we arrived. We quickly got into beach clothes and made out way across the road and down onto the long sandy beach.
It did not take too long for us to get tired, so we retraced our footsteps towards our entrance to the beach at “Sandy Cove.” I was surprised to discover that a large colony of wild freesias had established itself along the dunes at the entrance of the beach, and I spent some time among them, smelling and photographing.
I was aware that Freesias have established themselves in parts of Australia, and are regarded as weedy pests in Victoria and in South Australia and West Australia, but I have never seen such a large colony growing in the wild in our country.
As I would have expected, the colony at Gisborne seems to be largely formed of hybrids from F. alba, and most of the flowers are white, with a significant proportion having purple-backed petals, although there are also some creamy coloured forms, and some lovely mauve-flowered plants too. I even found a few with very attractive markings.
They reminded me very much of the large plantings my mother used to have in a very dry spot facing north, under her bedroom window. In this hot bed, a jumble of bulbs, mainly from South Africa, battled it out with each other for floral supremacy. The Freesias were regular winners in early spring, and a wide range of small flowered hybrids, in muted tones, flowered each year.
I am sure the Gisborne plants are fence-jumpers as I saw a number of wonderful borders filled with the white Freesia ‘Burtonii’ in beachside gardens on another stroll through the Wainui village. I guess the predicted global warming might mean this plant could become more of a problem in beach areas, but it was great fun to see these plants growing wild.

My own Freesias were in flower when we arrived home from our trip. I have pots of the golden double flowered form ‘Yvonne’, and of the deep purple single form, ‘Blue Navy’ –well, they were labelled ‘Blue Navy’ when I bought them, a double form, but they are actually singles.
I also have ‘Attica,’ another modern hybrid, this time white, growing in a pot. This variety has bulked up quickly but its growth rate is nothing like that of the old fashioned ‘Burtonii’ that most gardeners are familiar with.
This was a chance sport of F. refracta alba, and arose in the Nelson garden of a Mrs Burton, after whom it is named. For many years this was by far the most popular Freesia in our country. Its creamy flowers, with their bright golden spot and absolute absence of any purple staining, made this enormously popular. Over recent years this variety seems to have lost its vigour and it is harder to find in garden centres.
Some years ago I was given a double-flowered form of F. refracta alba. I have never seen this offered in nurseries, so it has probably only been passed from bulb lover to bulb lover. It is small flowered and has a messy centre but it is an interesting old plant.
The Freesias at Wainui Beach have colonised so well because they carry prolific amounts of seed – except ‘Burtonii’ which is sterile. The gardener can use this proclivity to their own benefit buy raising crops from seed. Most reputable seed companies stock at least one mix of these and they are easy and fun to grow.