Q. It seems, all of a sudden, my 18-year-old piñon pine is dropping a lot of brown needles. When we have a big wind, the area under the tree is littered with a lot of them. Is my tree in trouble? – G.P., Albuquerque
A. You’re going to want to get out and visually inspect the piñon.
If this year’s new growth – called a candle – and last year’s needles are still green and firmly attached to the tree, and it’s the needles from three seasons ago (the growth of 2019 and older) that are browning and falling, then I don’t think the piñon is in trouble.
That is the tree doing what comes naturally. Think about it. This year’s candles and last year’s needles are the ones that are receiving the most sun. They are the tree parts that are doing the photosynthesis, feeding the tree.
Those three season and older needles have successfully filled their job for the tree and are no longer necessary, so the tree drops them.
Internally (I believe), the tree shuts down all of the veins or avenues the needles had and, essentially, since their usefulness has been completed, they are starved and, in turn, they fall off.
The tree just doesn’t need them any more, so why expend all that energy trying to support them? The tree says, “I know, I’ll just let them fall off.”
If that’s what is happening, then I wouldn’t worry over your piñon, just keep the spent needles swept up and the area kept as tidy as you do.
Now, if during your visual inspection, you’re seeing lots of this year’s candles showing signs of distortion or browning, the tree could be hosting pine tip moths and that’s not good.
You could snip off one of the candles and cut it open, lengthwise, to see if you find a caterpillar-looking larval bug. If you find any then I’d recommend snipping off as many of the distorted candles as humanly possible, and treat with a systemic pesticide.
As the tree absorbs the pesticide and sends it to the new tips, any creature eating the “wood” ingests the pesticide and in turn dies.
But the tree will not be able to recreate this year’s candles, so it’ll be sort of distressed until next year’s growing season, and it’ll be up to you to vigilantly tend the tree.
Offer it adequate water and being sure to keep any dead tips cleaned and swept up as religiously as possible.
Next year, in very early spring, treat again with the systemic pesticide so the tree will already be wearing protection if any pine tip moths lay eggs on next year’s candles. We’re talking late February, early March for that pesticide treatment.
Now, if during your visual inspection, you see any wee black dots holding fast to last year’s needles or dotting the already fallen needles, then that is a different issue.
That could be the telltale evidence of pine scale. I would recommend spraying the tree with a summer grade horticultural oil pesticide soon.
The oil coats and in turn suffocates the bug living under that scale covering and it dies.
It’s a fairly safe treatment, rating-wise, but I will ask that you be sure beforehand that there aren’t any active bird nests in the tree before you spray. A nest of young birds would be impacted for sure if they were sprayed by any pesticide treatments. It won’t be long and the young will fly the nest, giving them a better chance at maturing.
So, get out there and visually inspect the branches and needle patterns to get a handle on what could be, and is, going on with the piñon, but, from your description, it doesn’t sound like the tree is in trouble. It’s just doing what comes naturally and that’s a good thing.
Happy Father’s Day to all you Dads while you’re out there Diggin’ In.
Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM 87109, or to firstname.lastname@example.org.