Tuesday, 26 December 2017

Post 248 Next stage for the air layered Clerodendrum

In my last post I covered the air-layering of this large trunked Clerodendrum hetrophyllum. This picture shows the air-layering in progress with the dam still in place around the cut site.

And then after separation and repotting. I also trimmed back the branches and foliage to reduce the dehydration load on the tree, having reduced its root capacity.

 Now just two weeks later and every branch cut is reshooting, with multiple shoots at each site.
This is typical of Cleros and it is one of the reasons why the species is such a good bonsai subject. An abundant capacity to shoot back on bare branches makes for easy bonsai development.
At separation it had a very good root supply and so in the last two weeks and has firmed up nicely in the pot. It's prime time to get on with the next stage of the rejuvenation work.

 Looking into the basic structure of the tree there is a straight section of the upper trunk which visually conflicts with the rest of the attractive taper and movement.

The branch structure is also pretty poor. Not nearly enough branches is the common failure of many bonsai. That trunk really deserves better and so I'm going to have to start again from scratch. When the tree was collected there were branches cut off leaving a number of flat faced scars and deadwood. The existing branches developed from the callus tissue that formed around these old cuts.

In repeating that process of branch renewal it is likely that new branches will again come from callus around new cuts and I may not get enough branches again. If that happens then I'll use grafting to get the right number and location of branches. I have lots of cuttings struck in small pots ready to go for just that purpose and over the next couple of weeks will get them ready for hairpin grafting.

 Here you can see the section of trunk that has to go. The branch to the left of the intended cut will provide an opportune apex.

 Branches coming off.

 And more.

 Removing that trunk section down to the left hand branch stub.

 Final view from the front.

 From the right.

 From the back.

 And from the left hand side. There are lots of cuts on the trunk. Some are from the removal of recent branches and some from the scars from the original removal. I've carved out concave cavities in all of them and then sealed (not shown here) them all with cut putty to seal them up and assist recovery. With peak summer temperatures and plenty of water I'm expecting it to produce new shoots within a few of weeks.

Sunday, 10 December 2017

Post 247 Air layering of a Clerodendrum

This is a story about the air layering (or ground layering) of a large club tree, a Clerodendrum hetrophyllum, that was done at a club meeting on Sept 23.
The 'Clero' is a fantastic species for bonsai in this part of the world. It's a native of Reunion in the Indian Ocean and it came to tropical coastal Queensland in colonial days as a hedging plant for gardens. Since then it escaped the confines of gardens and is somewhat feral in a number of locations. But its still a great species for bonsai, robust, shoots back, small leaves and great fibrous bark.

The first three pictures are of the trunk of the tree from a number of different directions.

  Suffice to say the nebari was pretty poor, comprising of very large primary root structures and no fine root development and trunk flaring. It was this poor appearance that was the motivation to complete an air layering or ground layering, to build a quality nebari to match the trunk.

  This is the start of the work. Once a line was drawn around the base, the cut could be made.

  Having cut and removed the ring of bark, plastic sheeting was placed over the surface of the potting mix to make with a tight fit against the trunk of the tree. The purpose of this sheet is to minimize any upward root invasion of the planned layer potting mix. Without this barrier the tree's roots would rise up into the potting mix placed around the cut and confuse the signals about the layers success.

  Here the dam (just a cut off garden pot) is placed and filled with regular potting mix.

  This is a picture of the tree 11 weeks later on December 9, just before stage two of the layering - the separation.

  The first indication of success of the layering is roots just below the surface of the potting mix. With the plastic sheeting in place it is unlikely that these roots have come up from the original root mass.

  By just lifting slightly the dam wall the second favourable sign is more root evidence.

  Taking the dam away entirely reveals very healthy and abundant root development.

  Here the surface is raked away from the trunk to reveal very good root development from all around the trunk.

  The pot was then tipped on its side to look between the plastic sheet and the layer cut to confirm the roots have come from the layer cut, making separation possible. Here you can see the major components of the original root structure where they have been cut through. There was a handsaw in the previous picture but this cut needed a chainsaw.

  This picture shows the root development from the layering. To prepare for planting the roots were gently raked out radially from the trunk so that as they develop and gain weight they will be aligned to create an attractive nebari.

The final picture shows the tree returned to the poly box to grow on and stabilize. The branch structure was trimmed back to reduce any wind load and also to reduce any dehydration pressure from the much reduced root mass. At this point the tree is just experiencing what any other tree would during a spring root prune and will no doubt respond in the same way, with abundant growth. After a month or so for new roots to grow and stabilize the tree, the next stage in the rejuvenation can start - building a new branch structure - one that reflects the broadleaf character of the species and will leave the future bonsai looking like a tree!