If you purchased a pine at a nursery that had been sheared in the early stages of growth, it will be compact and thick, with branches closer together. If you want to keep the pine looking like it did when purchased, you need to prune it every year.
What happens when you don’t prune it is that the base of the tree to the height it was when purchased, stays more compact while it continues to grow. The top part of the tree opens.
After a few years, the branches eventually open and it’s not as noticeable. The point is, if you are going to prune a pine tree to keep it full and thick of branches, you need to do it yearly.
For instance, Christmas tree growers shear pine trees every year to keep them nice and thick so that there will be lots of branches for ornaments.
Unsheared trees tend to have lots of open space between branches and branches are sometimes weaker and not able to hold heavy ornaments.
A Mugho pine or a dwarf cultivar shrub type pine can be pruned easily each year and kept compact and full. However, it must be done this time of the year and before the new growth hardens off.
Right now, in the Miami Valley, pine buds have opened revealing what is called “candle” growth. The tips of the branches look like a slim candle.
These candles elongate and the needles open, showing the new growth. This growth is soft and tend when it first opens.
Eventually, usually by mid-July, the new growth hardens and becomes woody. It’s too late to prune a pine if you want more growth next season.
Pines have buds only on the tips of the branches whereas other conifers have buds up and down the branches. Spruces, taxus, firs, and others have buds along the branches that continue to grow despite the tip being removed by pruning.
The branch of a pine, on the other hand, if removed, will not continue to grow as there are no lateral buds.
If may sound a little confusing but all you need to do is look at a pine tree and compare it to a spruce tree right now. You see lots of growth on the branches of a spruce, and only growth on the tips of the branch of a pine.
Pruning pines is easy and can be done either by pinching the candle or using pruning shears. The further back you prune the candle, the shorter the branch growth for this year. I tend to prune about half of the candle.
If you are wanting to limb up or remove the lower branches of a pine, you can do this any time of the year.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at bennett.27@osu.edu.