Watering Pine Trees – Water Deep!

Q. I recently moved into a condo that has pine trees on the property. Some of them look like they aren’t growing much but those still in grassy areas look much better. Some other pines have branches that are dying back. Do I need to supply water to these trees?

The very new growth in the spring of pine trees are called "candles" because they look like candles. All the new growth for that pine tree is contained in that candle. If water is available to the tree, candles will stretch and get big. If water is limited, the candles will not stretch and the new growth will stay small.Notice the buds at the base of the candle. I will talk about these buds in the next picture.

A. All of this is not simply a water issue. There is probably a disease problem going on as well. But first things first. Pine tree branch growth, and how dense the tree is, has a lot to do with how much water it receives in the spring and early summer months. Just as important is how deep the water drains in the soil, to encourage deep root growth, after it’s applied.

Branches of pine trees are in the whorls along the trunk. In the picture above, you can see the buds at the base of a candle. Those buds will grow into limbs that are in whorls around the trunk.

            Most native pine trees grow along canyons or stream banks where water is plentiful in the spring months and less available later in the season. Water availability coincides with spring growth which in turn increases the tree density.

            Water pine trees deeply, particularly in the spring months. How deep? Water should drain 24 to 36 inches into the soil each time it’s watered. To make sure it’s deep enough, measure this depth with a long thin metal rod like a piece of rebar. Plenty of water this time of year helps push new growth. This new growth supports the needles responsible for a dense tree canopy. Deep irrigations are important later in the year, but less often, to maintain this density.

This blow over can happen to trees when they receive shallow irrigations and shallow applications of water. This is a mesquite but it can happen to pine trees, and does. Water large trees deeply to avoid blow over during strong winds. With deep irrigations, roots will grow deeply.

            Lawn watering only applies water about eight or 10 inches deep. This is not deep enough for large pine trees as they get bigger. Watering lawns with shallow irrigation may keep the trees denser but it doesn’t encourage the deep roots needed during strong windstorms. Besides the lawn water, large pine trees should get periodic deep watering as well. Pine trees in lawns may look full but they usually will blow over during windstorms as they get bigger.

Aleppo Pine Blight is classified as a disease but there is no known pathogen or living disease agent associated with it. In extreme cases it can cause entire branches to die. But the tree with this problem should be and Aleppo Pine, not a different type of pine.

            Branch dieback of pine trees is usually a physiological disease that cannot be cured called Aleppo Pine Blight. In most cases, new pine needles in the spring replace the dead needles lost during the winter months.