The idea is to set the branch firmly in position, not to constrict it. Since Time is a tool used by bonsai enthusiasts, we must look forward in time and see that by wrapping the branches too tightly, as the tree grows, the wood beneath the wire swells, increasing in diameter. In short order the wire will bury itself in the bark, ruining the design and greatly harming both the health and beauty of the tree. So, we wire just a little loosely to allow for branch growth, and to allow for more time to pass between wirings. For tropical and semi-tropical trees, this rule too applies, but even more so.
Tropical trees can be rampant growers, and can outgrow a wiring in as little as ten days' time.
Many tropical bonsai enthusiasts find that using as little wire as possible makes for a more healthy bonsai. Bonsai Techniques vols. Used under License. Then gather your roses now while they are fresh.