Mastic Tree Problems

Q. Can you tell from the attached pictures what might be happening to our mastic tree?

Mastic tree.

A. My guess is that the new growth is filling a “hole” made when the plant became a shrub. Mastic is a Mediterranean tree or shrub that grows slowly and naturally as a bush, to about 20 tall by 20 feet width. It requires, at the least, annual pruning when it is young to shape it into a single or multitrunked tree. It is best used as a background tree or shrub and not a smaller version of the larger Chinese pistache. It is not as pretty. It lacks fall color, tends to be shrubby, and smaller, but does have red ornamental nuts when they are young and before they ripen around August.

            If this plant were mine and I wanted a small tree instead of being shrubby, as it tends to be, I would start to prune it in the winter or late fall months. Make a decision whether you want it as a single or multi trunk tree and make the appropriate cuts.  I would expose the trunk or trunks of this tree up to my knees by starting at the bottom of the tree. I would eliminate any growth below my knees and keep any upright growth. If I saw any suckers at the base, I would eliminate them. While it’s young, I would eliminate any growth growing downward or horizontal. I would concentrate most of my pruning efforts on keeping any upright growth to make it look like a tree and give it some height.

            Water it like you would an olive tree. It is mesic in its water use. It will attract the leaf footed plant bug. Shearing this tree with hedge trimmer is a mistake. Fertilize this tree once or maybe twice lightly with a standard landscape fertilizer such as 16-16-16.

Sap Coming from Small Fruit Trees Usually Borers

Q. I have some newly planted peach and nectarine trees with sap coming from them. They don’t look healthy.

Sap oozing from newly planted fruit trees nearly always borers.

A. Borers are most likely the problem. On small, newly planted fruit trees it doesn’t take many borers to kill the trees. They usually “attack” the south or west sides of a trunk or the limb of a tree. That’s where there is sun damage. Painting these trunks and limbs with white latex paint lowers the surface temperature about 4 or 5 degrees. It may be enough in some cases. But shade is better.

Borers will usually start to damage the hot side of a tree, either west or south.

            The sun plays a role also. Direct sunlight on the trunk of a thin barked fruit tree can be a problem. The “smell” of sunburned and dying or dead limbs and trunks attracts female borers that are looking to lay their eggs, scientists believe. When limbs and trunks of newly planted fruit trees have sun damage, then borers are more likely to be found.

This is a locust tree. Borers "smell" or find their way to the sun damaged areas of any tree. Here the top of the branches have been damaged by the sun. The bottom of branches out of sunlight are undamaged.

            What to do? 

Shade the young tree from Western and Southerly direct sunlight. Paint the trunk with diluted white latex paint. As a last ditch effort, drench the soil around the tree after it flowers (if possible) with a borer systemic insecticide and don’t eat the fruit for at least 12 months after the application.

Which came first? Here sun damage eventually led to borer damage.

If Fruit Trees are Planted Correctly They Can Take the Heat

 Dig the hole three times WIDER than needed. Plant in a wet hole. Amend or mix that soil or bring in different soil.

The planting hole is dug three times wider than you need it.

Amend or mix the soil with about 20 to 30% of a very good compost.

Mix in a good compost when planting.

Stake all fruit trees. Make sure the trunk cant move when you are finished.

Stake fruit trees, all of them, so the trunk can't move.

Protect the fruit trees from rabbits with chicken wire for the first three to four years if you live near a golf course or an open desert.

Put at least two inches of mulch (wood chips that rot) on top of the soil. Three inches is better. Keep it 6 to 12 inches away from the trunk until the tree is six years old.

These are wood chips from whole entire trees, not bags of wood bark.

Water every other day or every third day, wide and deep.

Poor Canopy Development in Newly Planted Large Tree Could Be Lack of Water

Q. I think I this might be a pink locust tree. I'm seeing a lot of dead branches. The tree was planted last Fall. Should I give it some fertilizer to help it push out new growth?