Tuesday, January 22, 2008

African beauties

In the middle of summer, when the heat really goes on, we need plants that are going to cope with extreme temperatures, and with lowered moisture levels. It should come as no surprise that many of the plants we look to provide us with colour and life in the mid-summer garden will be coming from the drier areas of the word – South Africa, Australia and the drier parts of the Americas.
I have a particular fondness for the various South African daisies – and there are very many different species available.
Last year’s Ellerslie Flower Show did not feature many flowers, with foliage and decorations being more predominant, but there were tubs of wonderful Osteospermums in full flower.
These flowers have only been very popular for the past twenty years or so. They are commonly called “Cape Daisies” - although they do not have that name to themselves as other members of the vast daisy family are also known by that name – and were once known under their old botanical name Dimorphetheca.
Twenty years ago there was a very restricted range available – mainly white and mauve-pink – and they were grown as seaside perennials, although they are almost hardy in our part of the world. They were also used a lot on banks and walls, as their prostrate habit made them very suitable for such use. They were sunny weather plants, the flowers not opening in cloudy days, or in poor light.
Then the whirligig varieties appeared on the market. These had many spoon shaped petals, and were quickly popular.
Then the Dutch plant breeders got hold of them, seeing a huge market for improved varieties to be used as summer bedding. They have vastly increased the colour range and have also introduced reliability and disease resistance.
The spoon-petalled varieties are released under the name of “Nasinga”, and are available as white, cream, pink and purple. The thinnest part of the spoon is considerable thinner than in older varieties and the flowers look startling – almost space age if you know what I mean. They will not be to everyone’s taste but they are certainly eye catching.
The colour range among the other varieties now includes white, pink, lavender, purple, copper-purple, yellow, cream and apricot. Many of the varieties have two-toned flowers, usually with brighter, deeper colours on the outside of the petals. “Warembo Arwen”, with yellowish flowers, and “Nuanza,” with copper purple flowers, are the ones that I like the most.
These will do very well for summer bedding, as previously stated, but they are also fabulous for growing in hot, dry beds, and, even more so, in containers. They will not mind drying out too much, and will cope in soils with poor fertility. They do not like shady areas, and demand full sun.
Gazanias are also deservedly popular daisies, and have been popular plants in New Zealand for a long time. There are many un-named forms floating around, and many seed grown forms. I like to change my containers every year, trying our new varieties to see whether they are useful for the garden. This year I planted up a pot of a new Gazania called “Stars and Stripes.” These have bright flowers with deep coloured stripes, but I have to say that they are nothing extra special, and a few cuttings from almost any wild gazanias would have done as well.
I planted these with a much more interesting choice – a cereal! I had seen the millet “Purple Spear” in a garden centre the year before and been tempted, but this time I could not resist it. It grows like a dwarf sweet corn, but with deep green foliage edged with purple. The flowers are held on deep purple stems, and are even deeper purple, with golden pollen. I planted a few of these in the centre of a pot of Gazanias, and the effect is great. This plant would also work very well if mass planted, with golden or silver foliage to set it off.
There are some stunning new Gazanias on the market, with bigger and fuller flowers, and denser growth. The best of these are from an Australian breeding programme and have been available in New Zealand for a couple of years now.
“Sunset Jane” is a lovely variety, with coloured, fully-double flowers in shades of
honey, amber and burnt orange. It forms a rounded clump with grey foliage and is s stunning plant with subtle colours.
“Montezuma” is also a fabulous plant, with glorious flowers that change as they age. When young they resemble a wagon wheel with lemon-to-gold fine petals radiating from a bold centre. As they mature, the petals broaden and open to reveal a stunning purple shade with white tips. The leaves are green in this case.

Monday, January 14, 2008

One of my obsessions during the teen-age years (one of the more socially acceptable one!) was a passion for science fiction writing. I have long ago out-grown the fascination, but a little residual memory of it catches up with my every now and again.
It also catches up with my younger son, Owen, who has love of theatre and film – one of his favourite shows is the musical version of the odd “Little Shop of Horrors”.
The unifying feature of much of the science fiction I used to read, and the slightly camp story of a nerdy florist with a problem plant, is that within both genres, flesh-eating plants are the norm.
My guess is that many of the plants that feature in this fiction are based on one or two real plants, the perennially popular Venus Fly Trap in particular.
The Venus Fly Trap comes from very swampy soils in both North and South Carolina in the United States. They are such iconic plants for botanists and gardeners alike (as well as sci-fi writers obviously!) that they are endangered in the wild.
They come from wet soils with very poor fertility, and have developed methods to obtain their nutriment needs from the environment. The “traps” are especially adapted leaves with a series of special hairs protruding from the surface. When an insect lands on the leaf, and moves across it, it springs the hairs, which act as triggers to close the leaves. The insect needs to move across a number of hairs – just one will not trigger the process_ presumably an evolutionary defence against wasting energy trying to digest dirt and dust.
The “trap” has guard hairs on the outer rim, and if the insect that triggers the hairs is too small to be nutritionally viable, the leaf will not close properly, allowing the insect to escape. Similarly, if the trap is triggered by a stone of piece of bark, the leaf seams to be able to recognize this, and it opens again after about twelve hours, and ejects the foreign object.
If the leaf traps an insect, such as a fly, the process goes into overdrive. The guard hairs, cilia they are called, hold the prey within the leaf, which closes tightly enough to be water-tight. The plant then secretes digestive juices (rather like the chemicals our own stomachs use!) which break down the soft, fleshy parts of the insect, leaving the hard exoskeleton behind. When the prey has been digested, which takes from about five to ten days, the juices are re-absorbed and the trap opens again. The dried-out skeleton is exposed to the wind and soon blows away. No-one is quite sure how the plan achieves this trick, as it obviously has no muscles or a nervous system- the best guess is that differences in fluid pressure are at work.
This is a popular plant with young men. When I worked in the retail end of the horticulture trade, we had a steady demand for these insect-eating plants from such customers. Every now and then, one of the local boarding schools would have a craze on them, and we would have lots of fifteen year olds looking to buy them.
Fortunately they are not very hard to grow as long as one or two points are kept in mind.
Firstly, these are plants from warm and moist climes, and need similar conditions to grow well, especially over summer. Ideally, they should be grown in poor, wet soil, so the best bet is to use a mix of sand and sphagnum moss. Do not add any fertilizer nor any lime, and make sure the rhizome is flush with the top of the mix. Just keeping the water in the saucer underneath the pot should keep the humidity about right.
The plants need good light and warmth, but you will need to be careful to avoid exposing them to full sun near a window as they will wilt in extreme heat, especially if they are a little dry. One solution might be to grow a plant in a terrarium, where the humidity levels will be naturally high.
These plants come from areas with cool winters, so they will need a period over winter when they can have a rest. That is simply a matter of ensuring that they are a little cooler, and the watering can be slightly less during this time too.
You cannot use a Venus Fly Trap to keep the flies under control in the house, as each plant only requires about two small flies a month. I imagine that many plants are killed by inquisitive young men feeding the plants with pieces of hamburger, fried bacon and luncheon sausage.

Friday, January 11, 2008

Spikes and all....

I have an intriguing old book on my shelves, a settlers’ guide. It is a compendium of all sorts of information for new settlers heading west across the vast North American landscape. The publishers assumed that there would be a demand for a book that could guide these new adventurers on all aspects of their lives, and they filled the large volume with information on all sorts of things.
There were plans for homesteads and dovecots; information on different cereal crops; details on aspects of veterinary care; sketches of rudimentary surgery needed in times of accident; recipes for fireworks, and of course, a section on gardening.
The gardening section is largely concerned with the provision of foodstuffs for the family, but there are also some pages devoted to ornamental horticulture.
The first time I glanced through these pages I was amused to find a new classification for plant types. This book does not group plants according to their family or genus – instead it states that there are only four types of trees - columnar, round-headed, pyramidal and weeping. It is certainly an interesting way to divide plant types.
This classification system was bought home to me again recently as I have been contacted by a few people about rosette forming plants flowering for their first time, and wanting identification of these plants. In our climes it is almost always one of two plants that people are talking about.
The first of these is one of the most spectacular of all flowering plants, the so-called “Sapphire Tower”, Puya alpestris. This looks for all the world like some kind of weird cactus as it grows. It forms a rosette of greyish-green leaves, symmetrically arranged, and edged with hideously sharp spikes. As the plant matures the rosette gets larger until it is about two metres across.
It then throws up the most amazing flower stem. At first the stem looks like a large silvery asparagus spear, but it grows rapidly until it is about two metres high, then the flowers themselves appear along the stem.
The colour of the individual flowers is almost impossible to adequately describe. I have seen them called “iridescent, peacock bluish-green” by an author, who then confessed that he found the flowers impossible to describe, and said the colour could not be found on any colour chart.
These flowers are set off my bright orange anthers, and last about three or four days, although a succession of flowers will give a relatively long flowering season.
This exotic beauty is in fact of the vast bromeliad family, hailing from Chile, making it a distant cousin of the pineapple. It seems to be quite hardy in our area, as I have seen plenty of plants growing out in the open. Most bromeliads are very particular about having good drainage so I suspect that would be its prime cultural requirement, and plenty of summer moisture.
It is not often seen in garden centres, but if you are looking for a really exciting accent plant for your garden, it is well worth hunting this beauty out. Do not plant it too close to the front door though, unless you are trying to discourage door-to-door salesmen, as the spikes will happily spear anyone or anything that gets to close.