Summer growth on black pine

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As is clear from the photo, each spring shoot has been replaced by somewhere between 2-8 shoots.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.