Decandling Pines: Summer Lessons from Mirai
From June 4–6, I had the awesome opportunity to study at Bonsai Mirai under Ryan Neil, diving deep into the developmental strategy behind decandling pines. Decandling is the process of cutting candles (the newly elongated growth of a pine) at the base (not below the base, not above- right at the base). While many think of decandling as simply removing candles to achieve a second flush of growth, the reality is more complex and powerful—it’s a tool for development, thickening, building length, and balancing foliage.
Here’s what I learned—through demonstrations, discussions, and hands-on work—about when and how to decandle, what species it applies to, and why it matters.
Understanding Tree Strength and Decline
A pine’s strength is greatly tied to its root health, vascular tissue, and how energy is distributed across the tree. At Mirai, Ryan emphasized the ability to work on a pine is determined by its strength- has it been re-potted this year, is it strong and healthy? If there are health problems, they are evident in the foliage growth. Barring insects, problems with foliar growth in the spring is usually the sign of a root problem (often too much water or heavy root work), while fall foliage decline can often be caused by imbalanced strength in the crown.
So before picking up the scissors, we ask:
- Is this tree strong enough to work on and where is it strong?
- What developmental stage is it in?
- What’s our goal—thickening? Backbudding? Refinement?
Developmental Stages: A Structured Approach
One of the main themes that occurred to me was actually sitting down and defining what stage each of the pines in my collection was at- It makes the work and decisions for action much clearer before I’m sitting in front of a tree tempted with scissors in hand. A clear way to look at pine development is that it follows three stages based on goals:
- Developmental Stage: Focused on building primary structure, thickening, and healing. Here, we let the tree grow strong. We are not concerned about balance, node or needle length. Backbudding and vascular growth are encouraged to lay groundwork.
- Secondary Stage:
Once the primary form is 70% of what you want it to be (length, thickness, etc), we begin building interior branching. We primarily use wiring a branch down and out to push energy inward, but also use pruning and decandling to reduce apical dominance, and start forming future pads. - Tertiary (Refinement)
The final stage is about shortening internodes, reducing needle size, and balancing energy. Decandling, needle plucking, and shoot selection become precision tools.
Very rarely will you have 100% of a tree, 100% in one stage. Branches on the same tree are often in different stages and have different goals eg. one branch needs thickening (developmental), one branch needs more back-budding (secondary) but it takes two strategic prunings to successfully transition a pine between these stages. For multi-flush pine that is generally one full year (two decandlings), for single flush pine that can be trimming pre-flush branches in spring and post-flush growth in late summer.
Multi-Flush Pines-
Japanese Black Pine, Japanese Red Pine,(less reliably so Loblolly Pine, Slash Pine, Austrian Pine, Pitch Pine, Yellow Pine, Aleppo Pine)
For pines like Japanese Black Pine, decandling is a vital process. We remove spring candles in early summer- (typically middle of June), prompting a second flush of growth that leads to:
- Ramification
- Shorter internodes
- More compact foliage
- Better foliage balance
This only works if the tree is healthy and in the secondary or tertiary phase. During the development phase, we mostly avoid decandling unless we’re working on specific sacrificial branches. At this time it is also important to needle-pluck to match the weakest branch’s foliage- typically 5-7 pairs of needles around the base of a candle (more if a tree is weaker). This helps to further distribute hormones and ‘balance energy’ across the canopy.
Short needle Single-Flush Pines-
Japanese White Pine, Mugo Pine, Scots Pine, Lodgepole Pine, Mountain Pine
For single-flush pines, we do not ‘decandle’ but similar timing concepts apply. Instead of forcing new growth, in development, energy is manipulated through:
- Pre-flush tip pruning (early spring)
- Wiring
- Post-flush harden-off pruning (late summer)
- Needle plucking in fall (to 5-7 pair of needles on strong trees) to open up space and rebalance
These procedures again help create back-budding, establish length and thickness, heal wounds and, achieve ramification and balance in the canopy.
In the secondary stage, a post flush harden prune and needle pluck is key and in the refinement stage pinching buds to balance energy and needle plucking furthers refinement. It is helpful to think that in these stages our direction is set and we’re just refining it.
One key takeaway: secondary branches must reach at least 50% of the strength and development of existing branches before transitioning to refinement. Otherwise, backbuds won’t activate properly.
Unlike multi-flush pines, balancing energy in a tree happens over several years rather than several seasons. Fall or late winter is the best time for structural pruning, wiring and (after spring) is the second best time for repotting.
Long needle Single-Flush Pines-
Ponderosa Pine, Eastern White Pine, Western White Pine, Sugar Pine, Limber Pine, Jeffrey Pine
“You manage long-needle single-flush pines by manipulating strength, light, and timing—not by decandling or forcing second flushes.”- Ryan Neil. The traditional ‘stages’ of development are more fuzzy here and are on much longer timelines.
For five-needle pines, (Japanese White Pine, Eastern White Pine, Western White Pine, Limber Pine, Sugar Pine, Swiss Pine, Whitebark Pine) we allow the natural sheath drop and decandle only as a process to control internode length, not to create ramification.
For two-needle species (Mugo Pine, Scots Pine, Lodgepole Pine, Mountain Pine, Ponderosa Pine, Jeffrey Pine) fall is the key window to rebalance (light pruning and needle work) before the next vascular push in early spring.
Timing Is Everything
At Mirai, I learned that decandling is not a shortcut—it’s a developmental milestone. When applied correctly, it reshapes the tree’s growth pattern for years to come. It’s really the process by which we ‘build a pine’ But mistimed or misapplied, it can set development back.
As Ryan put it, “It’s not just about cutting—it’s about having the right conversation with the tree at the right time.”
Whether you’re developing thick branches or refining pads, decandling is part of a longer journey. And like everything in bonsai, it starts with observation, intention, and an understanding of the tree’s natural rhythms.
– Mark Britton