If Your Pines Turn a Weird Grey…

michael hagedorn

…they might not be dead, they might have spider mites.

Mites are sneaky little arachnids that can transform our trees while we’re busy assuming all is well, to turn around one day and think, huh, wasn’t that a darker green last week?


Pine showing spider mite damage from the year before, on the older needles with the yellow stippling

The spider mite—there are several species—often forms a visible webbing if it lives on a juniper, but the webbing is often not apparent on a pine. In both instances the mite leaves a yellow stippling of the needle or leaf if seen close up, and a graying if seen from afar. The mite sucks out the interior of a cell and causes it to lose its green color. A tree can survive repeated mite attacks for multiple years, but it does keep the tree in a weakened state and should be…

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Be a Bonsai Sleuth: What is Needle Cast and What is Overwatering for Pines?

michael hagedorn

Many of the problems we see on our bonsai look very much the same. Needle Cast, a fungus, and overwatering, a care mistake, often look a lot alike.

Here are two photos that might help determine if you have one or the other of them in your yard:

This pine, a Ponderosa, has been overwatered. Notice the nearly equal lengths of browned tips. Whenever you see this, think, ‘This soil has stayed wet for too long.’ It may be because of water retentive soil, or perhaps it’s been watered too frequently. Adjusting the watering pattern for this tree, or changing its soil, should solve this problem in a year’s time.

This Ponderosa Pine has Needle Cast, a fungus. Notice the discoloration, the uneven browning of the needles, and the the green/yellow/red banding, especially in the green parts of the needle. The treatment for this tree is spraying with Daconil or…

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