Foliage on the tree will start to yellow and drop; smaller branches will shrivel and die back. As the live portion of the root-ball becomes even smaller, it is eventually unable to support the primary branches and the trunk, causing the tree to die.
Any time you cut a plant above a node, the section of stem left above that node will die back to the top node. So if you were to leave 1/2" of stem below the bottom node, it would just die back anyway.
Leaf and Branch Pruning: Cypress need to be constantly pruned to allow light into the deeper reaches of the tree, otherwise die back occurs and no re-growth will occur, which can be a major bonsai headache.
Pruning should be avoided to prevent excessive die back. In late winter, the tree is getting ready to send the stored nutrients back to the branches and buds.
In young plants, branch tips turn brown and die back until the whole branch or young tree is killed. Trees over five years old are less susceptible. When older trees in landscapes are affected by tip blight, entire trees are seldom killed.
A small cut on a growing vein will probably callus over, but a large cut of an entire vein or large branch will probably die back without any callusing.
Also note that Ficus aerials will die back if they are not rooted into the ground and the trees are subjected to normal typically low home humidity levels.
They are unable to outgrow infestations and as a result extensive die back and even death of the tree can occur. However, being fairly small and manageable, bonsai are usually easy to treat.
If you begin to prune them off as they emerge you weaken the plant and many of them will die back. Let them grow out about six to eight inches, or more, so they can harden and have a better chance of surviving.
To prevent die back, prune only when the tree is actively growing. With terminal pruning the reuse will bud back easily.
When new shoots have developed to around three to five nodes - prune them - but make sure to leave at least 1cm (1/2in) extra to allow for die back. This is something important to do when pruning all types of Japanese maples.
Zone 8 plants should be kept in a cold frame to protect the delicate twigs as well as the roots from die back. Zone 7 trees I would mulch into the ground in their pots or just protect them from Northern exposure.
 See also: Bonsai, Plant, Tree, Pruning, Growing
|
