Distinguishing old growth from new growth on junipers

A recent hot spell left its mark on a number of trees in my garden. On the day temperatures peaked, brown needles appeared on some Sierra junipers.

Brown needles on Sierra juniper

While brown needles can be scary, it really depends on which needles turn brown. If the old needles turn brown, it’s good to note, but not necessarily cause for concern.

New growth is green, old needles are brown

Seeing the contrast in needle color reminded me of some of the first bonsai instructions I ever heard – “remove the old growth from junipers before wiring.” I remember at the time finding it difficult to distinguish the new growth from old. Looking at these sierra junipers makes it easy to see which is which. When cleaning up junipers, these old needles can safely be removed whether they are green or brown.

The old needles can be safely removed

Another clue that can help distinguish new growth from old is found at the foliage tips. Green and healthy tips indicate young, active foliage. Foliage with brown, grey or dull-green tips indicate older shoots that we can safely remove.

I saw an interesting example of this at a recent Bay Island Bonsai workshop. A member was working on a juniper that had been pinched by the previous owner to the point where it had become quite weak. The new owner left the tree alone while it regained health and was now going about the cleanup. As you can see from the photo below, none of the pinched foliage was growing – the only healthy shoots emerged from the end of the branch.

New growth emerging from the branch tip

This may not cause problems if you want the branch to be longer, but if you want to keep growth compact – the typical rationale behind pinching – it can be counterproductive. As the old foliage has stopped growing, it’s safe to remove it and proceed with styling the tree using the healthy foliage at the end of the branch.