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A common challenge for bonsai practitioners is learning not to do too much to a tree. Over-working a bonsai will slow development or even kill it. I’ve learned this lesson over and over, and have started to become more patient in recent years. More than ever before, I find myself making the conscious decision to do nothing, leaving a tree to grow out even when I am eager to style or do some other operation. Today I am learning that it is also possible to take “leave-it-alone” too far.

Letting a tree grow out to build strength can be an effective strategy. As I am learning today, however, it is possible to leave-it-alone to a degree that will hinder development just as badly as over-working.

The Squamata Juniper, Juniperus squamata, shown above was being left alone to grow, but I should have been watching it more closely. It was starting to develop a pretty significant foliar mass (which is great!) but you can also see that something is wrong. There are many browning patches.

Some of the brown needles, those lower down on the branches, represent a normal growth pattern — the three-year-old needles turn brown as the branch underneath lignifies into a brown woody stem. The brown needles at the tips, however, are a real problem. The culprit in this case is scale.

Those little white specs along the leaves are adult scale insects, sucking away at the sap and hunkered down under their protective, waxy scale covering which protects them from topical pest controls like insecticidal soaps and oils. These treatments ARE effective on the microscopic juveniles, but you have to catch them at the right time when they are still moving about on the tree.

Now that I have left it alone too hard, what am I going to do?! I’m going to do four things.

  1. Remove old brown needles so they can’t be used as hiding places when I use topical insect treatments. Before and after is shown below.
  2. Treat with neem oil and repeat every 7-10 days to catch and stop any new life cycles.
  3. Remove badly damaged tips and along with the still-attached adult scale. See image below.
  4. Treat with a systemic insecticide to kill the remaining adults.

I am hopeful that this combination will take care of the infestation, but this is a significant setback for the plant. The dead tips I had to remove should have been the growing tips that provide for the future of the tree.

For each shriveled tip I had to remove, I have to hope new buds will take over further down the branch.

The scale has reduced the health of the tree, so guess what I need to do now? I need to leave it alone — but not too much! I will watch it much more closely over the coming months to make sure the scale is totally cleared up, and to watch for any other problems. As much as I have been looking forward to styling this tree, I will have to wait until it is back to a state of strong growth.