I'm Rusting

The aspen on the right in our backyard pair has chlorosis, the inability to take up iron in the soil. Without iron (and sometimes other minerals), the leaves don't photosynthesize well.


They turn yellow, which is what makes the smaller tree look lighter in color. Chlorotic leaves are yellow in between dark green ribs, like the leaf below on the right. The cluster of leaves below is from the healthy tree, the close up of the yellow leaf with dark veins is from the sick one.

Usually iron deficiency is because the soil is too alkaline, but right next to it a healthy green aspen grows well. They are so close their roots are intertwined. I'm not sure it's soil ph.

Instead, I think it might be drainage. Aspens are sensitive to water -- too much, too little or too slow draining. When I dug around the smaller aspen's roots to amend the soil with an iron supplement, I found waterlogged, soupy mud. In a drought.

I had been watering the aspens during this dry winter and spring, and somehow the dirt on the right side just doesn't drain. All of the trees are planted in small spaces between garages and house structures, and it's probably awful soil. That section is compacted and heavy. Maybe it's better where the healthier aspen sits.

In any event, I moved the gravel away, dug around in the mud below and added iron sulfate at the roots.


We'll see if that will help. It usually doesn't, despite the fact that there is a huge industry devoted to selling us stuff like this. It's hard to change soil chemistry for very long, and it's going to be ineffective if the real problem is soggy drainage.

But I added it anyway. It's iron, just as the bag says. It's a white powder that turns rusty when watered in. The gravel mulch is all reddish brown now and my clothes are rust covered and I can taste metal on my lips. When I come in to wash up there is rusty water swirling down the sink drain.

At least I don't have chlorosis.

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