Every year, we spend time discussing the what, when, why, and how for summer candle-pruning of 2-needle pines (typically Japanese black and Japanese red). Here is some information about the process, and photos will be added over the next few weeks as the work is done.
Definition: Current season’s growth is removed from 2-needle pines. This is the coniferous equivalent to defoliating deciduous trees.
Purpose: Removing current season’s growth creates ramification, shorter “internodes”, and shorter needles.
Timing: Current season’s growth is removed after needles have fully extended and hardened off, and while there is just enough time remaining in the growing season to produce a new flush of growth (+/- 100 days). Red pines and corkbark black pines need more time, and should be pruned earlier. Standard JBP are done later, and Shohin JBP should be done last, so the new needles are in scale with the design of the tree.
#1. Remove weak/smallest candles first. 10 days later, remove medium candles. 10 days later, remove the remaining, strong candles.
Rationale: Removing the weak candles first gives the weaker branches a head-start on growing new buds, which will help balance the strength of the tree. By the time 20 days has passed, and the strongest candles are removed, the weaker branches have already begun budding.
#2. Remove all candles at once, leaving a large stub on strong candles (equal to 1.5x the width of the candle), a smaller stub (equal to .5-1x the width of the candle), and no stub on weak candles.
Rationale: Similar to above, the varying lengths of stub help balance the tree. In this instance, the remaining stubs can be compared to fuses on firecrackers! The wound dries and lack of auxins trigger the tree to bud again. The longer the stub, the longer it takes the tree to respond by producing new growth.
Caveats: This is not to be performed on 5-needle pines, nor should it be performed on a weak tree.
- Determine if candle-pruning is necessary for the tree.
- If so, count backward from average first frost date, to time the pruning to give the tree 100 days to form new candles. In Birmingham, the average first frost is November 1, so candle pruning begins in early July.
- Identify weak, medium, and strong areas of the pine
- Locate the base of the current season’s growth (current season’s stems are green, last season’s stems are tan), and remove weak candles in their entirety, leaving last year’s growth.
- If following method #1, simply wait 10 days, then remove medium candles. If following method #2, continue removing all of this season’s growth, leaving a length of stub commensurate with the strength of the candle.
- If a significant disparity in strength exists, remove some of this year’s needles from the strong candles, leaving 4-6 pairs around the tip of the candle.
- When all of the current year’s candles have been removed and new growth begins to appear, remove any extra buds to leave only a pair of buds at each tip. Ideally, the pair should be relatively equal in strength, and across from one another, at 9:00 and 3:00 positions.
- Feed well, and ensure they’re in full-sun, all day!
More as the season unfolds, I’ll be adding photos of the candle-cutting process with this tree, 15 months into bonsai training:
And this pine, which is chronicled over the last 6 years in this article: http://www.nebaribonsai.com/Nebari_Bonsai_112109/Projects_files/Candle-Cutting%20071011.pdf