More banksias

A couple of my smaller bonsai banksias started to develop dieback in some twigs toward the end of spring.

Many people would assume that, because these are banksias, the dead shoots would be the result of phosphorus toxicity. My experience with this genus led me to a completely different conclusion.

I have noticed that banksias have very dense fine roots that develop very quickly. Here’s what I found when this one was removed from the pot.

It definitely needs repotting.

First, trim back any long, fresh shoots.

When I cut through the root ball I found exactly what I was expecting – a dry patch in the middle.

That area is dry despite a thorough water last night and again this morning. The roots are so crowded that water has great difficulty penetrating which means the tree starts each day without a full pot of water. The dead shoots have nothing to do with P toxicity. They simply show a lack of water.

The remaining roots were trimmed quite a lot.

Note that there are no visible proteoid roots on this banksia because it gets regular fertiliser. Proteoid roots appear when banksias are short of nutrients and tend to disappear when the trees are fertilised regularly so paradoxically, regular fertiliser actually helps reduce the chance of P overdose for banksias.

Then back into the pot with fresh mix.

My experience with banksias as bonsai shows that the roots grow so fast that these need repotting every year to prevent them becoming root bound and having difficulties with water absorption. Fortunately they also seem very tolerant of the repotting process during the warmer months. This repot was carried out during a string of 40+C days in early January. New shoots continued to grow and more buds have sprouted since the repot. As usual, the freshly repotted tree went straight back to its usual position on the bench. The area is covered with light shade cloth this year but no other ‘aftercare’ was given.

I’ve found banksias to be very rewarding for bonsai. Why not have a try? Shibui bonsai normally has banksias available in a range of sizes including field grown trunks – see our banksia catalogue – hhttp://shibuibonsai.com.au/wp-content/uploads/2018/12/Banksias-2018-1.pdf

Banksias as bonsai

Summer has proved to be a good time to repot banksias and a couple of the shibui bonsai banksias were due for it this year.

When I first started to grow banksias for bonsai they were not very successful. Most just lasted a year or two then suddenly died. Given that banksias have a reputation for being quite sensitive I just thought the genus was not suitable then I started to see some great banksia bonsai and gradually pieced together a couple of important facts about banksia bonsai. Continue reading

Trident nebari

Spreading basal roots, known by the Japanese term ‘nebari’ is considered very important for maple bonsai. Surface roots are prominent features of old maples, pines and elms so these features are also valued in bonsai of these species.

Nebari should, ideally, spread evenly all around the base of the tree, showing enough to give the tree the air of age and stability. Continue reading

Repotting natives

I usually repot any native plants in November or December. There were plenty that needed doing this season because I had not repotted for a couple of years. I find that many native plants grow lots of fine roots in the pots and quickly get to the stage where there is no room in the potting mix for water or air to penetrate. This mans that it becomes increasingly difficult to keep the mix hydrated and I have lost quite a few trees because I have not repotted often enough. Continue reading

re-potting Callistemon ‘waterswept’

December is summer in Australia so here at Shibui Bonsai it is time to re-pot some of my native bonsai and potensai.

I started the day with my Callistemon ‘ waterswept’ bonsai. This one was slip potted into the current pot a few years ago but has not had a proper re-pot for quite a few years. It has finished flowering so it was time to stop procrastinating and get on with it.

before

 

Here is the tree before. The design is based on trees that grow in the bed of the nearby Ovens river with roots clambering over the rocks in midstream and all the growth battered downstream by frequent floods.

 

 

 

 

spent flowers

 

This one only produced a few flowers at the top of the tree this year. All the flowers have finished so it is a good time to re-pot.

rootball

after re-potting

After root pruning it was re-potted back into the same pot.
Potting mix is my standard mix with standard osmocote added.
I forgot to take a picture of the rootball after root pruning but the pile of old mix and roots I cut off will give you an idea how much the root ball has been reduced.

after pruning

After potting the tree back into its pot it has been given a final trim to remove the old flowers and any excess branches.
To get flowers next summer I must now leave the new shoots to grow and mature because Callistemon flower only on the shoots that grew the previous season.
Finally the tree is given a good soak in water then put back on its stand which is in full sun most of the day.