Summer is the time when people who decandled their black or red pines water and fertilize and wait until fall when the time comes for wiring and needle-pulling. Looking around my garden, I see summer growth in different stages of development and already I can tell which trees are too strong or not strong enough. How much I water and feed at this point will affect needle length, but the vigor I see now reflects the tree’s strength back at the start of decandling season.
On one end of the spectrum, trees produce short shoots with only a handful of needles each. This is fine for developed trees with lots of fine branches, but it’s a bit weak for trees that are early in their development. It’s not a problem – it just means that things are going slowly this year and that I won’t get a lot of new growth until next year. I want to make sure these trees gets lots of water, fertilizer and sunlight for the remainder of the growing season.
Weak summer growth – the tree is healthy but the shoots are short
The tree below has shoots that are a good size considering the current phase of development. More refined growth – shorter shoots – would be great, but I don’t expect that from this tree as there aren’t a lot of branches.
Nice compact growth
Here’s a tree with shoots that are the same size only the needles are further along.
Compact growth – new needles are extending as expected
Trunk detail – am happy to see bark like this after eleven years
Below, it’s clear that the tree is very strong. This is great but it means that the new branches I’m getting will be on the long side. That’s fine for now but it means I need to slow the tree down next year.
Vigorous summer shoots
How will I do this? One option is to feed and water less. As I like keeping trees healthy, I don’t plan to reduce the water or fertilizer very much. Another option is to decandle later. The later one decandles, the weaker the resulting growth.
A less obvious option is to avoid cutback this year and treat the tree the same next year as I did this year. How will this slow the tree down?
As is clear from the photo, each spring shoot has been replaced by somewhere between 2-8 shoots. By leaving many small shoots on the tree, the total growth the tree can produce will be divided by more branches next year. Even if I feed the same next year, I can expect shorter internodes simply because there are so many more branches.
Will leaving so many branches that emerge from the same spot cause swelling? Yes, but it’s likely that these areas are already too strong and will have to be removed entirely so swelling is not a great cause for concern at this point. I’ll do some cutback in fall or winter but I don’t need to worry about getting every branch down to two divisions – yet. Basic refinement will continue for quite a few more years on these trees.
Occasionally I see even more vigorous summer growth.
Strong summer growth
Why is the growth so strong here? It’s the result of heavy cutback. Removing large branches is great for stimulating new shoots but it can be awful for slowing trees down. Because these shoots are so long I won’t be able to use many, if any, of them in the final design. To slow the tree down, I’ll leave extra shoots during cutback this fall, cut back on fertilizer and possibly decandle a bit later next year.
What kind of growth am I looking for? Something like this.
Nice summer growth
This tree is ten years older than the above trees so there are far more small branches with which to divide the tree’s needle-production capacity. Because the needles are already quite long – I decandled this tree on the early side this year – I’ll watch the food and water carefully in hopes of not producing overly long needles.
Of the two young black pines below, which do you expect to grow more next year – the one on the left, or the one on the right?
2-1/2 year-old black pines
My money’s on the tree on the right. Not because the foliage is a darker green, but because the buds are so much stronger.
Healthy apical bud
The tree on the left is weak and has tiny buds. This is likely due to some stress on the tree such as infestation or aggressive repotting. As a result, the tree isn’t preparing for a vigorous burst of growth next spring.
Weak apical bud
As expected, the side buds on each tree are weaker than the apical buds.
Healthy side bud
Weak side bud – you have to squint to see it
If the buds on your pines are small, ask why that may be the case. There’s still time this summer to make corrections before these trees go dormant.
Back in July I treated a number of black and red pines for suspected root aphids (see “Why are my trees yellow“). I’ve noticed a few changes since then and wanted to share what I’ve seen.
- Some yellow growth has turned green
- The healthiest trees are sending out summer shoots
- The weakest trees remain unchanged
My biggest worry when drenching the two- and three-year old pines was that the treatments would damage roots. Although it’s far too early to tell, I can report that there has been no evidence to suggest catastrophic changes to the trees that were treated. On a more positive note, I’ve noticed a few trees turn from yellow to green. The new needles on the pine below were yellow before treatment. Although the old needles remain yellowish, the new needles have greened up considerably.
3-1/2 year-old black pine
I have no way to tell whether or not the greening resulted from any treatment, but I’m happy nonetheless as it’s a sign of the tree’s health.
Some of the healthiest trees are now sending out summer shoots.
Summer shoots on 2-1/2 year-old black pine
We often think of black and red pines as trees that send out new growth one time per year – two when we decandle – but healthy pines regularly send out summer shoots when they’re growing vigorously. This is particularly true of younger pines.
1-1/2 year-old black pine
1-1/2 year-old red pine with summer shoots
Pulling a flat out at random, I noticed that all but one of the trees had summer shoots.
1-1/2 year-old pines
These trees will all need wiring and repotting before next spring. In the meantime, I’ll continue to feed heavily to help the trees prepare for winter.
Decandling and cutback are great techniques for redirecting growth on black pines. Here are some examples. Tree #1 After eleven years, the trunk of the tree below has reached the desired size. Any further significant growth and the curves would begin to disappear. The goal for this stage of development is to reduce investment in the sacrifice branch and further refine the lower branches.
11 year-old black pine
Close-up of the lower branches
Tree #2 The goal for the tree below is to generate more branches low on the trunk. The escape branch helped the tree reach its current size, but further growth is not necessary as the trunk is now the desired size.
11 year-old pine
After decandling and cutback
Tree #3 The tree below is another future shohin black pine. I’d like the right side to continue to thicken so I left the right hand escape branch in place while reducing the escape branch on the left. I decandled most of the lower branches to encourage new buds close to the trunk.
11 year-old black pine
After decandling and cutback
The challenge here is getting summer buds to develop when the escape branch remains strong. I’ve experimented with this in the past and found that it’s not always easy to generate summer buds without further reducing the escape branch. I’ll find out in fall what happens with this tree. Tree #4 The tree below is slightly further along as the escape branches were removed last year. The goal is to replace vigorous spring growth with more refined summer growth. I decandled all spring shoots and removed extra needles.
11 year-old black pine
After removing extra needles