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

Autumn, the first magnolia bloom of late winter, a bridge and the lovely tree dahlias

Autumn down by our stream 

Metasequoia glyptostroboides or the Dawn Redwood in our park

It is indubitably autumn here. The deciduous plants have coloured and are dropping their leaves. The nights are cool enough for us to have entered the time of the year when we light fires in the evening. True, the daytime temperatures are still around 19 celsius and we are enjoying one of our prolonged calm, mild and dry autumns. But autumn it is.

The first blooms open already on Magnolia campbellii in Waitara! On May 15!

This meant I was a little surprised when I ventured out of our home bubble last Friday to see the first blooms opening on Magnolia campbellii down in our local town of Waitara. The tree hasn’t even dropped all its leaves yet but there are several blooms already open. Being right on the coast and surrounded by urban concrete and seal, the temperature is warmer there than in our garden. We won’t see the first blooms on our M. campbellii, which is the same selected clone, until the start of July. Each year I talk about that as the harbinger of spring and the start of a new gardening year for us. I am not sure I can keep saying that having seen it coming in to bloom so early. This is one of the reasons why M. campbellii is not suitable for cold climates. Certainly it will flower later in colder temperatures but it is still so early in the season that it can be taken out by frosts. Waitara is pretty much frost-free.

The wisteria bridge as it was last November when our little dot of a grandson last came to stay

The big project this week, for Lloyd at least, is replacing the decking and railing on the wisteria bridge. That man is worth his weight in gold, I tell you. The wisterias – white Snow Showers on one side and Blue Sapphire on the other – had grown so gnarly and strong that they finally brought the railings down. Now they are both lying on the ground, I can see how big they are and will reduce them by at least fifty percent before we tie them back in, keeping them to a single old trunk and one or two new replacement whips.

Built on an old truck chassis that is outlasting the macrocarpa decking

Dredging the memory banks, we worked out that it is 25 years since the bridge went in. It was constructed by a visiting German engineer who was odd-jobbing around the place. The structural frame is an old truck chassis that was galvanised before it was put in place. That is still in perfectly good condition. It is the timbers that have finally given up the ghost. Initially Lloyd wondered if we could get away with just replacing the uprights and railings that were clearly rotten, but as he deconstructed the bridge, it became clear that all the timbers needed replacing. The original wood used was all untreated macrocarpa (Monterey cypress or Cupressus macrocarpa) so it has done very well to last 25 years.

Progress is being made with new decking and railing supports

Fortunately, ours is a well-stocked establishment with large sheds filled with many useful resources that we may need one day, so we just happened to have a stock of suitable tanalised pine to replace the timbers. Because of my aversion to the appearance of tanalised pine in the garden, it will be stained dark charcoal and I expect it to look very smart. This may even be by the end of the coming week because Lloyd is a project-oriented person. Once he starts something, he likes to keep to the one task in hand until it is completed. This is not a personality trait either Mark or I have and we recognise the advantages of it in other people.

Dahlia imperialis way up in the sky. The white form comes even later in the season.

The tree dahlias are in bloom. Goodness but these are challenging plants to have in the garden. They are magnificent in bloom, that is true. But placing them in the garden is difficult. They are brittle, rampant in growth, frost tender and way too large to stake. Some of ours can tower up to four or even five metres in the sky so they are dependent on surrounding plants to hold them more or less upright. If they fall over, they then smother everything around them and If I go in to try and support that low growth away from surrounding plants, they snap off in my hand. Then when they are dormant, they leave a big gap.

These are certainly not plants for everybody and every garden and there are good reasons why you rarely, if ever, see them for sale.

From a previous season, ‘Chameleon’ I think at the front and ‘Orchid’ (which I hope we haven’t lost but I can’t see any flowers of it yet where I think it should be) at the top. Both Keith Hammett hybrids.

But is there a lovelier autumn sight than their blooms set against a blue sky? We only have half a dozen different ones – the pink and white forms of the species D.imperialis and four from breeder, Keith Hammett. ‘Chameleon’ is a good performing, more compact hybrid of Keith’s that does not shoot for the sky so is more amenable as a garden plant with pure yellow flowers in abundance but it still needs plenty of space.

One autumnal wind will blow the taller ones over but they are a seasonal delight while they last.

A beautiful deep colour on one of Hammett’s hybrids growing through the raspberry coop.