Flowering Shohin-bonsai are a challenge for many Shohin-bonsai growers. The shaping of flowering and/or fruit bearing trees or shrubs are most often deeply connected with the nature of the flowering tree. Fruits or berries are the outcome of flowers; therefore the flowers must be present and preserved to develop fruits. Not all flowers develop fruits or berries of interest, but the Crab Apple is an example of fruits of beauty and therefore worthwhile to strive for when searching for a flower and/or fruit bearing tree.
The challenge is to be able styling the bonsai in a satisfying shape preserving the trees ability to develop flower buds. By pruning often the flower buds are lost if this is not done at the right time, and in the right way.
Trees and shrubs either develop their flower buds in the same year on new growth, or at branches grown the year before. This is absolutely essential to know and observe. Also take in account that flowers develop most where light reach the branches, and produce a greater number of flowers on younger branches.
Flowers on previous years growth
Generally speaking trees and shrubs that develops their flower buds the year before the flowers opens, should not be pruned after the period these flower buds are set in summer and autumn. As a thumbs rule, do not prune this type of tree after July, in order to preserve the flower buds for next years flowering. If the tree still not flowers it can have a number of reasons. Stop pruning earlier to test if the flowers buds may have been pruned away by too late pruning.
Also notice that some trees avoid setting flower buds if they are in strong growth, using energy on branch setting in stead of flower production.
Flowers formed on current years growth
Trees, like Potentilla, form their flower buds on the current years growth, so depending on the growth habit avoid pruning tow or three months before flowering, so new growth can be left for flower buds to develop.
Practise and observation
It can be a challenge to find out precisely how a tree is treated correctly to develop flowers. Practise and close observation is essential to know your tree. But with practise you will know when to stop cutting so flowering is not ruined. Let your tree grow for a period and observe the development of the buds, how they emerge and when they open.
Notice that in periods you will need to prune for shaping the tree without taking care of flowering, because flowering is only for developed trees. Flowering slows the growth, and therefore not for training periods.
The styling of flowering trees
Flowering Shohin-bonsai may have a looser and a little more natural (looser) look compared with the more accurate and tightly formed bonsai like Junipers and Pines e.g.
The flowering Shohin-bonsai will look so because it is part of getting them to flower, leaving branches untamed for a period to form flowers. At the same time the styling adds the very essential feeling of the season, and a natural styled tree with flowers/fruits/berries add the beauty and natural feeling so very important for the Shohin-bonsai presentation.
Shrubs wanted because of their bark colour, like red-twig dogwood (Cornus sericea), the new shoot growth has more brilliant colour. Routine pruning at the base encourages new shoots, which have the desired red colour.
Spring-flowering trees and shrubs bloom on one-year-old wood (on the new growth from the previous summer ). Buds develops during midsummer and through fall, preparing for the following spring flowering, so if you prune branches and twigs after that, in autumn or winter, the flower buds will be removed, causing flowering to fail. Spring-flowering shrubs can be thinned in early spring before flowering or growth starts, or right after blooming ends.
Spring-flowering shrubs examples:
Rhododendron (Rhododendron lysolepsis), Satsuki Azalea, Deutzia (Deutzia gracilis), Crab Apple (Malus), Berberis (Berberis thunbergii), forsythia (Forsythia spp.), cherry (Prunus), quince (Chaenomelea spp.), spireas (Spirea var.), viburnum (Viburnum spp.), beautybush (Kolkwitzia amabilis), lilac (Syringa spp.), honeysuckle (Lonicera spp.), peashrub (Caragana spp.), and weigela (Weigela spp.), Hawthorn (Crataegus), i.e.
Summer-flowering trees and shrubs bloom on the new branches that grew earlier in the growing season of the same year; that means spring growth in the current year will flower later the same season if left unpruned after first basic pruning early spring. Summer-flowering shrubs are also pruned by thinning or rejuvenation in the early spring before growth starts.
Summer-flowering trees and shrubs examples: Cotoneaster, Snowflake (Weigela hybrid), Euonymus (Euonymus planipes), Blue mist spirea (Caryopteris x clandonensis), coralberry (Symphoricarpos), mockorange (Philadelphus spp.), potentilla (Potentilla spp.), Bumald and Japanese spirea (Spiraea x bumalda and S. japonica), Annabelle and Peegee hydrangea (Hydrangea arborescens ‘Annabelle’ and H. paniculata), shrub althea or rose of Sharon (Hibiscus syriacus), snowberry (Symphoricarpos albus), Boxleaf Honeysuckle (Lonicera nitida) i.e.