Yellowing leaves on a River Birch Tree

River birch is one of the fastest growing and forgiving trees! It can deal with a ton of different water/soil conditions and still do pretty well. can't thrive if it is starved for water, drowned, or grown in alkaline soil. 

We have hard clay soil with a ph above 8. And we have an 8 year old river birch that struggles each and every year. It has grown large and is extremely beautiful, but every year over 30% of the leaves turn yellow with green rib lines - iron chlorosis. See below:

yellow river birch leaves iron chlorosis

yellow river birch leaves iron chlorosis

yellow river birch leaves iron chlorosis

In the past, I have treated this by giving the tree Iron Sulfate. A small bag of iron sulfate remedies the situation within a week or so. But it's just a band-aid. The real reason this happens is not because my soil is deficient in iron (in fact, soil tests proved it's loaded with it!)

The tree just can't get the iron because of the high ph. So this year, I've started trying to change things for good.

yellow river birch leaves iron chlorosis

I peeled back the mulch layer under the tree and amended the hard clay soil with peat moss. I will also add elemental sulfur and start fertilizing the tree with coffee, acid loving fertilizer and rain water (the same as I do for blueberries.)

Changing the soil ph is a tough undertaking. It takes years and the soil will naturally work it's way back to it's "normal." So it's a life-long process. But it's worth it! Healthy trees are an investment worth making!

If you choose to use acid-loving fertilizers on your trees, be advised that you should not fertilize a river birch (or really ANY tree) in the summer. You should also be careful - or not fertilize in fall or winter. Trees put on almost all of their growth in early spring - so catch them before they wake up and give them a good feeding.

If you fertilize in the summer or early fall, the tree may respond with new growth that will a most certainly be killed in the winter. That will leave dead branches and  possibly open wounds for insects and diseases to attack.


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