Its surprising just how quickly you can achieve good results with these beautiful plants.
From a small cutting a pretty good shape and design can be achieved with the proper care and some careful wiring. This article will deal mainly with getting the plant to grow fast during development. One of the important factors is to know the characteristics of the variety you have chosen to grow.
Here is a Satsuki azalea 'Kanuma-no Kagayaki'. In 33 months, from a cutting just 7 inches high in December 2020 to the 24 inch high tree in September 2023. This is a fairly fast growing variety which thickens readily. With some more good fertilising and being allowed to grow freely the trunk will now start to thicken up nicely.
The best way I have found to achieve a good sized tree is to allow the young cutting to grow a single stem until the required height is achieved.
Remove flower buds to channel all the energy into growth.
Remove all side shoots until the main trunk is at the desired height. I find this a difficult thing to do as I also wish to use the side shoots as propagating material. When they have grown long enough to provide a cutting I cut them off but my results would be even faster if I removed these shoots before they developed and took energy from the leading shoot.
Regular feeding of organic fertilisers such as Bio-Gold or my own organic fertiliser and chemical fertilisers like IB4 and Miracle-gro ericaceous, and not root pruning the young trees it should be possible to achieve at least 2-3ft in height in just one or two growing seasons and from there another foot or two can be grown in the third season. It is possible to speed that up too but I don't have the facilities of growing in an open growing bed of azalea soil such as Kanuma or my own azalea mix. Only once the required height is achieved is it time to concentrate on thickening the trunk followed by developing the branches.
Watering is vital to azaleas. make sure to keep the plant evenly watered. Regularly use a full submersion watering to ensure that the soil immediately under the trunk (the 'SHIN') is well watered.
Test your watering technique by watering normally with a watering can or hose and immediately afterwards submerge the pot and soil completely in a large enough bucket. Watch for the bubbles which will indicate areas of soil that did not get wet using the can or hose. the more bubbles you see then the more you need to improve your watering technique.
Its still a good idea to use the submersion method regularly anyway.
Below is another example of the same technique using the variety 'Aozora'. From December 2020 to May 2023. This variety is not as vigorous as Kanuma-no-Kagayaki but is has a similar flower. It will also take longer to thicken up. The important thing is to keep the plant growing vigorously in order to develop quickly.
If the tree begins to lose this vigour it will take forever to develop it into a tree. The best way to maintain the vigour is to allow the really strong shoots to grow freely and then to prune the new shoots hard when appropriate, while keeping in mind your overall design goals.
Another good variety is 'Asuka' which grows fairly fast and thickens well too. A slightly different shape of flower with more pointed ends to the petals. Again this variety thicken fairly quickly so good results can be achieved in a short period.
Shinyo-no-Tsuki is a variety I have not had much experience with. It does grow vigorously and thickens fast too although it is not quite as fast as other varieties. It does seem to be prone to bud drop if the surrounding air is too damp early in the season.
REPOTTING
Another thing that makes a huge difference to developing azaleas is repotting. This is where a lot of people make a big mistake. I repot azaleas in spring because it is simply safer.
Many say that they should be repotted after flowering but this puts the process in late spring/early summer when the weather is much hotter and management of the trees afterwards will be critical. It puts a huge stress on the trees when they can least deal with it.
One missed watering in the heat will mean almost certain death for the tree. Azaleas will not tolerate drying out and will suffer greatly if the soil is allowed to dry out too much.
I use pure Kanuma soil on azaleas that have come from Japan and have always been grown in it.
For my young plants and trees I use my azalea mix which is based on a recipe by Robert Callahams, an expert in the field of azaleas. I have found the performance of this soil mix to be remarkable. The trees love it and grow extremely well in it.
This is the recipe. 2 or 3 parts Melcourt Potting Bark : 1 part Kanuma : 1 part Pumice : 1 part Course Perlite.
Don't be tempted to plant your trees in training into bonsai pots. If you do that it will take you 20 years to do what you could have done in 4 or 5 years. Choose a pot that is in proportion to the plant.
Sticking it in the middle of a huge training pot is a bad idea too. The pot full of soil will retain a lot of water and the tree will be sat in a soggy environment for prolonged periods because the roots have not occupied the soil in order to take up and use the water.
Also, don't use a mesh pot or pond pot. These tend to dry out far too quickly and the azaleas will not do well under such conditions.
If you repot too frequently you will slow the progress of the developing tree for a period while the tree recovers from the disturbance. This can cost you many years in the development stages.
So, before you stress the tree with a repotting session, watch for signs of the growth and vigour slowing down. Water will not percolate into the soil properly if the plant is root bound. That doesn't mean that if the water doesn't drain instantly it must be pot bound. If you can stand there and watch as the water soaks in and drains through it probably doesn't need repotting.
If it is still growing well and making the vigorous, straight shoots that confirm that, then dont repot the tree.
Keep the trees cool in the hot summer times. When the weather is sunny it is all to easy to forget that the pots of bonsai get very hot in the sunshine. In hot weather a tree will shut down in order to preserve water. This means that they will not be transpiring as normal, and therefore unable to cool themselves through evaporation of water from the leaves. Obviously this will stop the growth which we want to avoid.
I have measured the surface temperature of pots at 55C on some of the hottest days. Your trees roots will not like this one bit and you may see signs of this heat stress with symptoms of dieback in the apex and some other branches although it is not immediately apparent. You will see it later when it seems that things are going very wrong with the tree. Azalea are 'surface rooting' plants and usually most of the roots are in the top few centimetres of soil.
So, in the hot weather, move your trees to a shady spot and keep them cool with a regular misting.
I will write another article covering the topics such as pruning, shaping, flower removal etc. at a later date.
I hope you find this article helpful. Please feel free to leave comments and add your experiences to the blog.
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