Sunday, September 27, 2009

Orchid season

There are some immutable constants in this universe; the speed of light never changes, pi is always the same, and each glasshouse, no matter how big it is, is always about 20% too small.
I thought I had addressed the smallness of my glasshouse (or polycarbonate house to be more exact) a summer or two ago, by expanding it by one fifth, but now I find, miraculously, it is still 20% too small.
Last weekend I pricked out this year’s crop of Pacific Coast Native Irises, and got the potted tuberous begonias out from under the glasshouse benches. They had spent the winter there, having a dry rest on their sides but it is now time for them to be kicked back into life by being watered.
I was scrambling for space. I had to shuffle around the various potted special plants, and even then could hardly fit everything in. I was especially keen to make some room because a friend had offered me some pots of one of my favourite plants, the little Australian Dendrobium orchids. As much as I tried, I just could not find any space at all.
That is a pity because this is the time of year for orchid societies to mount their spring shows. The Masterton show will be held on October 3 and 4, while the Hawkes Bay society will be holding their Sarcochilus show on November 7 in the Taradale Town Hall. The Masterton show will feature a large sale of very affordable orchid plants, and I was thinking I could expand my collection
I have a particular fascination with the Australian Dendorobiums – ‘dendrobes’ as orchid lovers call them.
They are derived from a number of epiphytic (growing on the bark of trees) and lithophytic (growing on rock faces or boulders) species, and they are smaller growing species (usually less than 30 cm) with reliable spring flushes of many flower spikes.
Again, they will do well in a special growing house with shade cloth walls and a solid roof to keep out the worst of the winter rains. Failing that, a nice north facing verandah will do fine. They enjoy the winter sun but need to be kept shaded over the hottest months.
I find they respond well to a small application of a long-term fertiliser. I know specialist growers go to all sorts of trouble, making up special feeding mixes for different times of the year, but for the average home gardener it is probably not that necessary – you will get perfectly fine results from the standard formulae.
Plants should be kept moist year round, although they can be allowed to dry oput a little in the middle of winter. Do not let them sit in water though, and make sure the pots are kept off the ground, as earthworms will enter through the drainage holes and make a mess of the bark mix.
The best-known species is he Australian King Orchid, Dendrobium kingianum, now officially Thelychiton kingianus. It is arguably the easiest Dendrobium to grow. It is the fastest growing and the most forgiving of all the Australian orchids, which makes it ideal for the novice grower. It ranges in colour from true albino white to a rich cherry purple, with bicolour shades of white with a rich violet eye. Breeders are currently working on lemon shades, true salmons and unusual sunset colours as well.
Take advantage of the opportunity to get along and see what specialist orchid growers are up to in their shows. Be warned though – you might find your glasshouse (or verandah) is about 20% too small.

Sunday, September 20, 2009

I have been thinking about English playwright Denis Potter this week, as the first flush of Japanese flowering cherries hit their peak. In a famous interview with the novelist Melvyn Bragg, Potter, who had recently been diagnosed with the cancer that was to kill him, described the view out his window, looking onto a plum tree in full flower. He said what he saw was “the whitest, frothiest, blossomest blossom that there ever could be”.
The past few weeks have been brilliant for blossom lovers. The relatively warm weather of August pushed cherries into flower a little earlier than usual, and they somehow managed to flower through a week without any substantial wind. And the effect has been magic, with huge clusters of flowers gradually building to a crescendo, then slowly going past their peak, and silently dropping confetti-like petals on to the ground beneath. If only every cherry flowering season could have been like this!
No wonder the Japanese go to such trouble with the Cherry Blossom Festival each year, as they since the 7th century. The festivals are held throughout the country to celebrate the arrival of spring. They are so important the national weather forecast includes a blossom forecast leading up to the celebration.
These trees have it all. In the main, the foliage is clean and attractive through the main growing season, often with the bonus of interesting new leaf colour in the spring, and a correspondingly exciting autumn colour later in the season. Even in winter, many of the varieties have interesting branching patterns only made obvious when the leaves have fallen.
Most of us think the very full double pink cherries when we think of flowering cherries, but interestingly enough, it is mainly the single white forms the Japanese treasure. They especially value these for the midnight viewing sessions they participate in.
Probably the variety they most treasure is ‘Taihaku’. This forms a tall growing tree with a large rounded crown, and has the most spectacular large single white flowers. These saucer-shaped flowers are slightly fragrant, best noticed in the warmth of a calm afternoon.
‘Shirotae’ is the famed Mount Fuji cherry, which forms a flat-topped tree with tiered branches that often droop to the ground. The pure white flowers are sometimes single, sometimes semi-double, and are scented of hawthorn.

Sunday, September 13, 2009

I took a lovely walk through our local park at lunchtime last week. My primary purpose was to go and check on the irises growing in the bed my grandmother donated to the town many years ago. I had weeded the bed a few weeks before, and knew the first of the flowers would nearly be out. Sure enough, there were a few flowers on the lovely gold and yellow form of Iris bucharica. This pretty species is the easiest of the Juno section – bulbs, but with persistent roots. It will grow in any well-drained soil and a sunny site, and is great for flowering in early to mid spring.
But it was not the irises that really took my eye – or my nos. It was one of the deliciously fragrant Viburnums wafting its delicious scent around the sheltered part of the park where it was growing.
I had been in a friend’s garden earlier in the week and was amazed to see four or five V. x burkwoodii growing around a relatively small garden. My friend loves scent and her garden featured a number of Michelias in heavy bud, so I can only imagine how fragrant her garden will be in a week or so.
V x burkwoodii is undoubtedly the most popular of the scented Viburnums. It has tight clusters of pure white flowers at this time of the year, with soft fragrance that I have seen described as being reminiscent of baby powder. It is certainly one of the few semi-deciduous shrubs that has retained its popularity over the years, and is perhaps among the top two or three scented shrubs grown in New Zealand.
It is a hybrid raised in Britain, between V. utile and V. carlesii. The former is an rare species in New Zealand, and I have never seen it offered. V. carlesii is usually findable and is a very fine deciduous shrub, growing about two metres high, although the specimen in the park was only just over half that. It was covered with the most delightful pink-budded flowers, opening to white, and scented even better than V. x burkwoodii in my opinion. It is hardy and, surprisingly, does well near the sea, but has never achieved the popularity of its child.

Sunday, September 06, 2009

The spring vegetable garden

September is a busy time in the vegetable garden, as the main planting and sowing season kicks in for most of us. By now you should have the soil well prepared and ready for the upcoming season. I generally do not use green crops, preferring to add a lot of compost to the soil but either way, you should have all this humus well dug into the garden by now. Make sure to keep the pH level up at the same time, by applying a good dressing of lime. The bacteria that break down the humus also tend to lower the pH, and frequent applications of compost can quickly diminish the pH level. I find a good guide is to use about a handful of lime to the square metre each year. If you have any doubts about the pH level of your soil, most garden centres have kits which you can quickly check it with.
It is also time to start sowing carrots, parsnip, beetroot, silver beet, peas, swedes and turnips. Most of these need a relatively high pH and lack of success with beetroot in particular is often caused by lack of lime.
We have very free-draining soil in the vegetable garden, created by years of composting. This suits most root crops very well, but it also seems to suit the carrot rust fly perfectly. Over the years I tried various advertised chemical remedies, but I have to say we did not really get the problem under control until I started using a blocking method. I created a large cloche, but instead of covering it with glass or clear plastic I used some white shade cloth. The cloche is made to fit snugly in our garden beds and has proven very effective at protecting our carrots.
Last year I decided to lift the cloche a little higher, as it had been constraining the tops of the carrots. I built a small wall (about 100mm high) to sit the cloche on. Later in the season I lifted the cloche, thinking the rust fly time had passed, but alas, I discovered that the flies found the carrots and severely damaged our winter harvest. I will not be caught out this season.
Most vegetables taste much better when just picked from the garden, but that seems to apply much more so for carrots – they are sweeter by a long way, and also far tastier. I like to grow one of the smaller types – a Manchester Table type – but last year trialled a couple of F1 hybrid varieties from my local garden centre. I have to say they both performed very well (until the rust fly found them) and I will be repeating the trial this year. If only someone could make a variety that was rust fly resistant.
Beetroot is a very reliable growing vegetable that that has a number of uses in the garden. The young leaves can be used in salads; slightly older leaves can be boiled or steamed, much the same as silver beet; the young roots are delicious when roasted whole, and of course, the mature roots have a delightful taste of their own. Those brought up on canned beetroot will find the taste quite different – not as sweet and slightly earthy - but they are very easy to grow as long as the pH level is high enough. There are lots of varieties to choose from now. As well as the cylindrical red type most of us are familiar with, there are cylindrical varieties, and there is a good range of coloured forms – orange, yellow and white for example.
Some garden centres sell beetroot seedlings now. Make sure you have enough soil depth to plant the entire root (it is quite long for such a small plant) and this will work fine. If you do not have a lot of garden room, the round varieties can easily be grown in a container.