Care and Cultivation of Bonsai

The determination of whether a bonsai tree is an "indoor" (tropical or sub tropical trees) or "outdoor" (suited the cool temperate climate of the UK ) variety is important to guarantee its' continued health and is simply a reflection of its hardiness.

Indoor bonsai are trees or shrubs that grow naturally in warm climates and will not usually survive outdoors during our cold winters. Because of their vigorous growth, water and repot more frequently.

Outdoor bonsai are temperate climate trees which are much hardier than "indoor" varieties. Some outdoor bonsai require extra protection in winter dependant upon their natural hardiness when grown in pots.


The most common cause of failure when growing bonsai is lack of water. When watering, apply to soil surface until water is observed to drain from drainage hole in the bottom of the pot. Water before the soil surface is fully dry. During the growing season, it may be necessary to water once or twice daily. During winter months, regularly check soil conditions and water as necessary.


Fertilise healthy trees once every two weeks during the growing season. Do not feed newly re-potted trees for at least six weeks. Use a balanced liquid fertiliser at the recommended dose, or a granular slow release feed. Excess feeding can damage bonsai.

Soil Composition and Re-potting

Bonsai pots in general are designed to allow adequate drainage and avoid water logging. Typically, pots have drainage holes and feet to permit circulation of air beneath.

Ideal growing medium comprises a soil mixture whose particle size is sufficient to allow good drainage and adequate aeration whilst encouraging healthy growth.

Re-potting is best performed in early spring just before bud burst. The tree is carefully removed from its pot and typically 20% of the root is pruned from around the periphery of the root ball. During this process some fresh growing medium is applied following removal of some of the previous soil. Care must be taken not to remove more than 20% of soil from evergreen bonsai although deciduous varieties will generally tolerate greater soil removal.

Shoot Pruning

This process balances root and shoot activity, enabling branch shaping and helps reduce leaf and shoot size. Shoot pruning is performed in the growing season in order to control excessive growth and establish the required shape.

Leaf Cutting

Only performed on vigorous trees; this technique involves the removal of some or all leaves in order to reduce the size of subsequent leaves. Never perform on evergreens. Leaf cutting is not performed until new leaves are well developed (earliest April/May) and results in better autumn colour.


Used when a trunk or branch requires shaping beyond that achievable by pruning. To form a suitable shape aluminium or copper wire is used. Remove wire after the branch is set and before scarring occurs. This typically takes a few months but could be achieved in weeks, or may take years.

Growing in Open Ground

A technique used for thickening trunks in formative years and producing trees of a size and quality for further bonsai training

Collected Material

The traditional approach in Japan had been to collect suitable material from the wild. The skill required to guarantee survival of the tree is a limitation to the success of this process. Should it be undertaken then permission must be obtained from the landowner and great care taken to protect the collected material. We as bonsai enthusiasts must not collect without great care and selection. We are open to criticism if we decimate the countryside

Nursery Stock

Bonsai can be purchased from specialist Bonsai Nurseries or suitable training material can be found in Garden Centres.

Cuttings and Seedlings

Excellent bonsai can be created from cuttings and seedlings but should be regarded as long term projects.