Seven days from the winter solstice – Tikorangi this week

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The white form of Dahlia imperialis

The last tree dahlia of the season is in bloom. Dahlia imperialis alba plena is the towering giant of them all, way up in the sky, not blooming until well into winter so particularly vulnerable to frosts and winter gales. I took this photo yesterday to show those in other climates the intensity of winter light that we get here on sunny days. It is different to those who garden where the winter sun hangs lower in the sky. We are not tropical; I don’t want to mislead. It is almost mid-winter and can be quite chilly. However, it is a lot less depressing to the spirits when you live somewhere with this clarity of bright light, even on the shortest days of the year.

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Miscanthus ‘Morning Light’ shimmering in the late afternoon light

IMG_7040We are now well into what Piet Oudolf refers to as the ‘fifth season’ and the new Court Garden brings me much pleasure, especially in the late afternoon when the sun is dropping lower and shines through the miscanthus grasses. I have used a lot of miscanthus running through the garden in waves and the plumes shine in the light and wave gently in any breeze.

IMG_7031IMG_7039I have finally found a place where this large yellow salvia can grow with sufficient space and it is a late autumn – early winter highlight. We have never had a name on this variety so if any readers can identify it for me, I would be grateful. It stands a good two metres tall so it is a large plant to accommodate. *** Now identified as Salvia madrensis, thanks readers.

Tips and techniques for the week:

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Stipa gigantea after a major thinning exercise

  • I took a before photo of this block of Stipa gigantea in the new Court Garden but I appear to have deleted it when I was filing photos. It looked fine at the end of its first year but I knew it wouldn’t stay looking fine and it was already too congested to allow the plants to fountain out and show their natural form. Last week, I took out well over half the plants and gave them away. I did have to lift some of the remaining plants to centre them to their own space but I am much happier with it now so it was worth the effort. I haven’t grown this stipa before and hadn’t realised how much space each plant needs. I am hoping this can now be left alone for a few years at least. It has a white field daisy growing between which I have learned I can get two, maybe three successive flowerings from spring to autumn if I cut it back to the base rosette at the right time.

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    Layering up the prunings at the back, more or less out of sight

  • Out of the ‘I thought it would be a straightforward job that would only take a day and a half at the most but actually took four full days and still isn’t quite finished’ school of thought, I spent this week clearing the wilderness of boundary plantings that separate the caterpillar garden from the boundary with the neighbours’ wool shed and yards. People with big gardens will understand that you have areas which get planted and then mostly left to their own devices. It is one of those jobs you finally tackle when preparing to open the garden to the public again. Nobody will notice I have done it, but they may well have noticed had I not. Over the years, it had become largely impenetrable with self-sown camellias, layered hydrangeas, native seedlings, especially kawakawa and various mounds of vegetation where I had emptied the wheelbarrow of prunings that I didn’t want in the compost heap. It amazes me how far I can get with a sharp pruning saw. Because there was so much of it, I dragged all the debris to the back and layered it by the boundary fence. At some points, it is quite a bit higher than in this photo. It can gently rot down there, adding humus and carbon to the soil and is a lot lighter on labour than carting it all away to compost and mulch. It is a technique we are using quite extensively now and is a tidy, unobtrusive way of dealing with excessive amounts of garden waste. That said, it is a big garden technique, rather than one for small town gardens.

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    On track to be an undulating, curvy hedge like a moving caterpillar

  • I have started a major clipping round on the hedges in what we call the Caterpillar Garden. The hedge is Camellia microphylla, already nearing the end of its flowering season. The plants were pretty neglected -raised from seed and cuttings many years ago and then left to kick around the old nursery until we were ready to use them. We planted them two years ago and the hedges, laid out in the shape of the basket fungus, are still a bit patchy. Mark’s plan is to clip these hedges into mounded, free-form shapes like an undulating caterpillar in the style we associate strongly with UK designer, Tom Stuart Smith. I am doing the first clip this season and have told Mark it is his job to come through and do the final clip of the top to get the mounding shapes he wants.
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    The straight-edged, hard clipped approach

    Most of our clipped hedges here are very straight sided with the top meeting at right angles. Lloyd does them with a string line to keep the lines straight and the hedges a uniform width. He has a good eye for these things. But after spending a fair number of hours clipping and shaping the caterpillar hedge, I can tell you that it is a great deal easier and more pleasurable to work with a more organic shape and form than that military regimentation of the sharper-edged hedges. Informality is much more forgiving than formality.

Escaped root stock

Many years ago, neighbours planted a row of flowering cherry trees on their roadside. Mark and I were discussing how long ago and he thought somewhere over 30 years, maybe even more. I recall when they first went in and they struggled for at least the first decade. There used to be quite a few more but these are the survivors.

We are not good territory for prunus and these were in a particularly exposed situation – windy, in other words. They may not have been planted very well but that is just a guess. To add insult to injury, I asked Mark if he could remember seeing them flower because it suddenly occurred to me that I had no memory of them in bloom yet we drive past them every time we leave our property. He couldn’t remember either so I guess we can conclude that the flowering is not anything remarkable at all, possibly occurring at the same time as the trees leaf up for spring. I shall try and take more notice this spring. They do at least colour up in autumn.

Two different growth forms on the same plant – one upright and one spreading

We can’t identify the variety but it is clearly not well suited to our climate and conditions. However, it is a named cultivar because these are grafted plants. How do we know? Take a look at this one in the row. It has the same spreading form as all the others but in the middle is this upright shape. That is escaped root stock.

There are many reasons for budding or grafting onto the roots of another plant. Some selected varieties don’t grow well on their own roots or can’t be struck easily from cuttings. Depending on the chosen root stock, it can either increase the vigour of the plant or it can dwarf it and slow it down. Fruit trees are often put onto dwarfing stock. If material of the chosen cultivar is in short supply, budding or grafting can make it go a lot further with a higher success rate in propagation. While it takes more technical skill to bud and graft than to take cuttings and the selection of appropriate root stock is very important, it is possible to get a higher percentage through the propagation process and to reach a saleable grade faster than from cuttings. Many plants are budded or grafted, Budding, by the way, is usually easier than grafting. Once the bud or graft has taken successfully, the original growth from the root stock is removed entirely.

When I looked at the base of the plant, it was clear that the upright section all came from one strong shoot close to the base – outlined here in red

Problems come when the root stock puts up a shoot that is allowed to grow and that is what has happened to this tree. Occasionally we get asked why somebody’s magnolia has two different types of blooms (one that flowered both yellow and pink comes to mind). It is always escaped root stock and while it may have a certain novelty value, it does not make for a good long-term plant. The root stock – which is commonly grown from seed and only chosen for its strong growth and good root system – on most plants is stronger growing and it will overpower the chosen plant variety in time.

I think this cherry tree may be well past the time when removal of the escaped root stock is an option but, to be honest, when the cultivar isn’t worth growing anyway, this may not matter much in the greater scheme of things. But I recommend that if you ever see strong growths rocketing away from the base of a tree or shrub, it may well indicate that the plant has been budded and it is best to remove escaping root stock when it is young.

Winter in Tikorangi

Finally, because it is indubitably winter here now, being June, I give you a Tikorangi winter. Vireya rhododendron ‘Jiminy Cricket’ in full bloom with a mandarin tree and Braeburn apple. It was this very mandarin tree that convinced me to live in Tikorangi. In my Dunedin childhood, the occasional bag of somewhat green, expensive mandarins was always seen as a treat. Tinned mandarin segments were reserved for decorating the Christmas pavlova. This tree showed riches the likes of which I had never seen before.

 

Things that go bump in the night

I was quite taken by this sight of epiphytes on a cornus tree down in the park. It is a natural occurrence here that I have written about before  – the establishment over decades of a matrix of interdependent growths spread by wind and birds which can thrive because of our particular climate.

Mark then asked me if I had seen the maple lawn. I hadn’t but there was the result of a branch on high collapsing under the weight of epiphytes, clipping the maple tree for which that small enclosure is named.

What you are looking at is somewhere close to three cubic metres of collapsed branch and epiphytic growth so there is a lot of it to clear. We had been watching that branch but as it was a good eight metres up and almost certainly rotten, the dangers of trying to remove it were potentially greater than leaving it to nature to take its course.

Even more two dimensional than it was just last week

I am amused by the small maple with its wonderful gnarled form. It has been somewhat one-sided for many years. In spring and summer, it forms a curtain of fine, burgundy foliage from its top to the base, but mostly on the side that faces the light. Now it is fully two dimensional. What few branches were on the shady side were snapped off by the falling debris. All I will do is trim any ugly, snapped branches back to the trunk. We can live with a fully one-sided maple tree.

This, too, will fall in due course

There is more to fall from above but it seems unlikely that will hit the little maple unless the remaining trunk snaps at the base. The tree beneath those epiphytes is a fairly unremarkable Australian native that neither Mark nor I can name, though Mark surprised me with the random information that he understands it has some culinary uses in traditional Aboriginal diets.

Sometimes I think that I forget to look up so this lovely sight above surprised me afresh, as it does every autumn. There is much to be said for a multi-layered garden as long as you keep looking at the various layers and not just at ground and eye-level.

Autumn at Tikorangi

Paint it black – the wisteria bridge

Tanalised pine

Two weeks ago, I mentioned that Lloyd was reconstructing this bridge. Twenty five years ago, it was built from untreated macrocarpa that we just left to weather naturally. Now it is tanalised pine and I am not a fan of tanalised pine in its raw state as a construction material in the garden.

Monet’s green bridge

Monet’s bridges at Giverny are painted green. It is not a shade of green I like. In fact, I sniffily refer to it as ‘lavatory green’, on account of it being the colour that Mark’s mother thought was suited for lavatories (and kitchens) back in the 1950s and 1960s when she was choosing the colour palette for both her new house – where we live now – and the beach house they built.

Poet’s Bridge, Pukekura Park (photo credit: Wiki Commons)

Locally, there appears to be a penchant for red bridges. I attribute this in part to the decision to paint what is known as Poet’s Bridge in Pukekura Park fire-engine red. Pukekura is the much-loved public gardens in the heart of New Plymouth.

The domestic version of a red bridge in a local garden – stained, not painted, by the looks of it

There also appears to be some idea that red bridges evoke the exotic Orient – well, China and Japan at least. This red bridge is a tidy little construction I photographed in a local garden.

A genuine Chinese bridge, festooned

When I went through my photos from our one and only trip to China (we will probably never will get to Japan now), I had a mental image of a red bridge but I see it was Mark and me on a bridge festooned in red ribbons.

The bridge at Yu Er Park was of somewhat showier design, but not red

Other Chinese bridge photos I had were more like this.

Our bridge gone black

Well, our bridge is now black. It is a bit blacker than I wanted it. Mentally I was thinking more charcoal off-black but it will fade because we have gone for stain, not paint. I am wary of painting anything in the garden because once painted, it has to be repainted as the paint peels and deteriorates. Stain can just age gracefully.

I hadn’t factored in the rather stark contrast of bird poop on the black surface but I am sure it will all find its natural balance over time. We have yet to tie the wisteria canes back in and that, too, will soften the sharp black lines. And one of the wisterias is white ‘Snow Showers’ so that will distract from the bird poop when it is flowering.

I am fine with the decision to go black and the bridge is a great deal more solid now than it was. There is no danger now of a bridge timber or railing giving way beneath the weight of an adult body.

Invasive plants

I don’t know its name. I am guessing it is a species.

Remember this pretty aster I showed in March? I loved its profusion and lightness. So did the bees and butterflies love it. But I was worried that it was too large and too dominant immediately by the path so set out to reduce its bulk and spread. That was illuminating. The initial divisions that I had planted were now so dense I had to cut them into squares to get them out but that was fine. What worried me was how far and how fast it was s p r e a d I n g. It had probably colonised its way out about a metre all around by sending out long runners below ground. The runners will put up a small rosette of leaves maybe every 20cm but they keep running and they are certainly aren’t going to let the roots of other plants deter them. Nor indeed were the stone edging or compacted path a deterrent.

That is about two years of growth in the pink tub and on the path and just from one patch.

By the time I came to the second clump, I decided on total elimination and that turned into quite a major operation. The first clump, I just tried to reduce and thin somewhat but I am pretty sure I may have to carry out more drastic action next year.

I am trying some in a confined drum and will see how that works. It is such a lovely plant in leaf and flower that I want to keep some of it but I really don’t want it invading large areas. Come to think of it, it may be the same aster that took over the Missouri Meadow at Wisley, choking out most of the other plants.

We inherited several old tanks with holes in the bottom that I am now using to contain plants that look dangerous

We are extremely cautious about invasive plants in our garden. Make that our country, not just our own garden, because garden escapes of invasive plants are a major problem in the wild. I like to shock overseas gardeners by telling them that it is actually illegal to grow the giant gunnera where we are in Taranaki. It became a noxious weed on the coastal cliff tops near Opunake where eradication was such a huge issue it was banned altogether. Our soft, warm-temperate climate makes plants which may be called ‘vigorous’ or ‘strong growing’ in harsher climates downright invasive pests here. And it is not just gunneras. Agapanthus, flag iris, campanulata cherries, the bangalow palm (Archontophenix cunninghamiana) , erigeron daisy, pampas grass, perennial sweet peas, Fuchsia boliviana  – our country is littered with plants that are a great deal more prized overseas but either discouraged, banned from sale or banned entirely in some areas here.

My gardening friend from Christchurch, Robyn Kilty recommended Calamgrostis ‘Overdam’ as a possible alternative to C. ‘Karl Foerster’ which had become dangerously strong growing here. I looked it up and found I can indeed buy it but the description from one producer included the terrifying words ‘may be invasive’. Make that ‘will be invasive’ in our conditions. Where Robyn gardens in Christchurch, such plants are not a problem with their cold winters and hot dry summers which restrict growth. There is no such brake on their growth here.

Some plants invade by seeding too freely. To some extent, that can be controlled by dead heading if the plants are lower growers. We dead head most of our agapanthus here and I dead head the likes of crocosmias. Or choosing sterile varieties can eliminate the seeding problems, especially when it comes to trees.

This white daisy – name unknown – is vigorous without being invasive. If cut back hard, it flowers a second and even third time which is very obliging of it.

Some plants invade by putting out runners along the ground which then make roots. Wisteria are a prime example of this and believe me, you do not want to plant wisteria unless you are willing to restrict them and prune them at least once a year. Somebody once told me that the largest plant in the world is a wisteria which has layered its way along. I have no idea if that is true but I wouldn’t be surprised.

And some plants, like the aster (and indeed the calamgrostis) invade by determinedly spreading their roots below the ground. They are way more problematic though you can resort to spraying with herbicide if you use it. The underground spreaders tend to be very strong indeed, choking out the competition and getting their roots intertwined with anything in their way.

I have kept six plants of Calamagrostis ‘Karl Foerster’ to see if I can contain them by root pruning them once a year with a sharp spade. I think I discarded 18 of them and digging those out was a major effort, I tell you, after only one year in the ground. I had to barrow in quite a few loads of soil to fill the holes that were left.

Mark is going to try some of the aster down in the park meadow where the competition from other plants is greater and the area is mown twice a year so that may curb the rampant growth. If it doesn’t, he will have to reach for the herbicide.

A profusion of aster that looked as though it had the potential to turn into a takeover by aster