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Pinus radiata was first introduced into Australia in the early 1850’s but was not commercially planted in large numbers until the 1960’s.  Since their implementation as a commercial timber crop, Australia has planted around 740 000 ha of the pine.

In plantations, seed produced by the pines germinates readily and many seedling pines can be found around areas where plantations are present.  As Australia doesn’t have any true pines native to it, these plantation escapees are the closest thing to the yamadori pines of other countries that we have.  In fact, the radiata is such a vigorous grower and reproduces so easily that in many states it is declared an invasive noxious weed species.

Pinus radiata or ‘The Monterey Pine’ although prolific as a timber species around the world is not commonly used in global bonsai circles. This is perhaps because it is a little quirky when grown as bonsai.

They have a lot of traits that make them ideal for bonsai. Fantastic bark, vigorous growth, highly flexible and the availability of ‘wild’ stock to be dug up all add to their bonsai credentials.

The needles of a mature Radiata bonsai

I have been growing a number of Radiatas and I am still yet to find the magic bullet for refining them.

Black pines seem difficult to grow until you understand their growth patterns and then prune, candle cut and needle thin at designated times of the year. The result of working within their growth habits produces neat and small needles and a large amount of back budding.

Radiatas I have not found as easy to master.

When I first started growing them I was told how easily they back budded and that you would have ‘almost too many buds’. This sounded too good to be true, and during the subsequent years of growing them I unfortunately found this to be the case.

The other problem I find with them is their needles. They can often be long, twisted and curled, but on some trees (one of mine being a key example) I have noticed shorter, neater and straight needles appear after the previous year’s unruly growth. This gives me hope that I may be able to work out a way to evenly force a neater shorter needle length by working with the tree’s growth cycles.

I have received a whole range of advice on taming this species. This has covered a whole range of often conflicting techniques, see below:

  • Treat them like a black pine
  • Treat them like a white pine
  • Pinch them constantly like a juniper
  • Wire one side completely, then later wire the other side
  • Pot them in an open mix
  • Pot them in a heavy mix
  • Break candles in half
  • Remove new growth totally

Over the next couple of posts I hope to generate some discussion with other growers that may dispel some myths and share successful techniques with the wider bonsai community. So if you know anything about Radiatas or grow them at home and are having similar problems please send me an email (Look under ‘contact me’ in the left side bar) or add a comment below.

To get people thinking I have included an old golden statements article to kick off the discussion that was written by Nancy Eaton on Mr Katsumi Kinoshita back in 1984. I used it as a starting point for my trees. Have a read and let me know what you think. Does the way you grow radiatas differ from those of Mr Kinoshita? I would love to hear about it. Next week I will begin to post about my experiences with the species and some of the things that have shown good results and others that have not been as successful.

Click to enlarge.

Click to enlarge.

Click to enlarge.

Click to enlarge.

Following on from yesterdays post I thought it would be good to include some examples of approach grafts that were at Taisho en while I was studying. The two examples below are using approach grafting for two different reasons. The first is grafting roots onto an upper section of a trunk to shorten a bonsai. The other is using the technique to both replace foliage and graft on new roots.

What do you do when you want to shorten the trunk of a species such as Tsuga that doesn't aerial layer well? Approach graft!

Here you can see some new roots being grafted to a Tsuga trunk. The roots have been wrapped in cloth and are both watered and fed as if in a standard pot.

The taxus tsuga above was an interesting bonsai with an un-interesting lower trunk. The image of the bonsai could be greatly improved by shortening the trunk and hence roots were approach grafted onto the trunk.

The below juniper was undergoing a major change too. It was a tosho or japanese needle juniper (Juniperus rigida). It was very large stock extending about 2-2.5 meters in length. It had some great movement and excellent jin/shari. The future for this tree was to break it up into sections. By grafting new roots and new foliage along the live vein at key points the large piece of stock would be able to be broken down into 3 or 4 bonsai, all with nice movement and good foliage. Shimpaku juniper was grafted onto the tree instead of more tosho as it is a more popular species and therefore easier to sell once the separation is complete.

As you can see this is a large piece of stock that is both too big to become an exhibitable bonsai (by Japanese standards) and the foliage is that of needle juniper which is not popular in Japan at the moment. How would you improve this material? Approach grafting.

In this case roots are being grafted onto a section of live vein in order to allow the entire trunk to be split up into smaller individual bonsai.

Hopefully from these two posts you can see the possibilities that this technique can provide. The ability to manipulate your stock and bonsai is a powerful tool in the bonsai artists arsenal. Shortening trunks, adding branches and changing foliage types can be controversial in some bonsai circles but I think that when push comes to shove the results speak for themselves.

I have been quite lucky that I have been able to visit a number of Japanese nurseries (SEE HERE). I love seeing the high quality trees and amazing level of finish and polish that these trees posses, but what I have also found very interesting during these visits is looking  into the back of house areas where bonsai are in various stages of transformation.

Air layers, grafts and other techniques are all on display out the back of most nurseries. It not only gives you a look into these techniques but also gives you some ideas on what sort of material to apply these techniques to.

One such technique is approach grafting.

A needle juniper is slowly changing its clothes. Soon it will be a much more valuable shimpaku. The white lump is the rootball of the scion which is wrapped in towel to protect its roots.

While I was studying at Taisho-en I was able to see this technique used to improve a range of stock. Shimpaku were given smaller foliage. Needle junipers were given shimpauk foliage. Roots were moved closer to the foliage to shorten trunks. It was obvious that after only a short stroll through their back of house that this was a valuable technique.

The technique itself, whether you are grafting on new roots or new foliage, is rather simple.

  1. Find a scion whip of the same species around 1-2 pencils thick and slice a sliver of bark off opposite sides at the point you want the whip to be grafted.
  2. Cut a channel in the trunk the same depth as the whip is thick.
  3. Widen this channel with a sharp knife to ensure clean cuts. The width of the channel should make a snug fit for the cut down section of scion.
  4. insert the scion into the stock trunks channel. Ensure that the cambium layers meet up accurately along the top edge of the channel cut.
  5. Fix the scion into the channel so it will not move or become miss-aligned. You can tie it with grafting tape or use a nail or two, screw etc.
  6. Cover it all in some type of sealant and wait for it to take.

I drew up a quick diagram to help explain the technique a little.

The scion whip can be from several sources. It could be a long branch doubled back on itself and grafted into the trunk, or could be a small whip that is growing in its own pot. If your scion is of the second type you may need to wrap the root ball in hessian or towel if the root ball ends up in a strange position after being grafted.

How long does the graft take to be successful? That is a difficult question. It is species dependent, growth dependent and also depends on how well you aligned the cambium layers in the first place. Although you can have success with poorly aligned cambium layers in this technique due to the face that both scion and stock support themselves before the graft takes, it is much faster to align the cambium correctly from the get go. I would say that most approach grafts would need one to two years to take. After that you could begin to reduce the original foliage over time and slowly let the new grafted foliage take over.

All in all it is a very useful technique that can be use to get you new roots, new foliage and generally improve difficult stock.

In the next day or so I will be posting a few examples to further illustrate the technique.

To see some real life examples have a look at “Approach grafting 2”.

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