So what is Post flush hardened pruning? When is it and why is it so important? For all our decidious bonsai we are desperately waiting for the time to get our brand new bonsai scissors out and start cutting. We all want that lovely bonsai shape and we are all want it NOW! So why must we be so careful and why must we always ask ourself one important question:
What am I trying to achieve?
Firstly, we need to understand that the period to get the most out of your pruning is at a time after the bonsai has had the greatest opportunity to restore all of its energy levels utilising the spring ‘solar panels’ (leaves). The leaves will have fully opened and formed cuticles to protect themseves from external elements. There is very little new growth and the tree is telling you ‘I have enough stored energy’ to get bigger. This is usually around the last week of May / first week of June.
But before we commit to the pruning process we have to understand what we want to achieve and ask these questions:
- Do I want the branches to develop & thicken?
- Do I need to heal new wounds?
- Is my bonsai unhealthy or recovering from a major re-pot?
- Has my bonsai shown poor Spring leaf production?
- Is my tree still in early development?
- Do I want the trunk to thicken?
If the answer is ‘yes’ to any of these then you will be leaving the tree alone or reducing the level of pruning to just specific zones. Certainly, if it is unhealthy or recently repotted you will probably just leave it. Remember, for most of our decidious trees there will be a second opportunity in late summer / early autumn.
So show me what to look for:
Although these images give you an idea of what to leave alone please remember that you will always know your tree best. Where branch development is required then I generally prune the apex and allow all of the energy to be directed toward the area I need improving.
So let’s get pruning…
Dawn Redwood
The Dawn Redwood is a deciduous conifer and is treated differently. The time for pruning is when the new growth stem has begun to turn a reddish colour indicating that it is now forming lignified tissue.
This is the only time of the growing season when you will prune this variety. Pruning any later than the middle of July allows insufficient time for new growth to harden off (it will drop in autumn).
In this image you can see two shoots that have elongated beyond the desired shape. However, the left hand shoot is green and therefore must be left alone OR removed if not wanted. The right hand shoot is ready BUT there are no new shoots on it to prune back to…
In this case the smaller right hand shoot is left alone whilst the dominant central shoot is clearly showing development of 2 sets of new growth and a growing tip.
If I wanted to thicken this branch then I would not prune but allow the growing tip to keep on going…
I have chosen to cut back to the first set of new growth. This should encourage buds to form behind the site of the cut. My aim is to build new shoots into branching and develop some ramification.
The standard advice applies with reference to the ‘rule of 2’. Any junction where more than two shoots originate should be pruned to reduce the prospect of inverse taper through swelling of that area.
The pruning is now complete and I have managed to keep a couple of the harder shoots for cuttings.
I have also cleaned out any unwanted new growth from the trunk and branch crotches.
I do not reduce the length of individual fronds.
That should be all I do until I decide on bud selection in the early spring of 2022. This is also when I will wire out the growth established this year.
This is the first of a series of articles I am posting this week covering the pruning principles for a number of different bonsai in my nursery.
Tomorrow we get to grips with the Trident Maple and Japanese Maple.
Happy pruning 🙂
