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I recently (spring 2009) planted a globe willow in Herriman, altitude 5300. I was told by an arborist that it should be okay as there are other successful globes in the foothills of the Quirrahs. It has now got leaves (May 2009) but they are getting yellow towards the mid to top and I suspect iron chlorosis. This is yellow, not the beautiful light green as usual.It gets good water and sun. It was planted with mixture of native clay, potting/planting soil and mulch including "mike" a good microorganism suggested for good plant rooting. Should I give it a dose of iron or let it be? Or us this normal? Help!

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I think you are in the west part of the valley, in the foothills of the Oquirrh mountains?  Globe willows are not generally recommended because they are highly susceptible to slime flux disease, and because of their branch structure to limb breakage.

As for the yellow leaves, if the veins are still green it could be iron chlorosis.  Iron chlorosis occurs with overwatering as well as high pH soils.  Plants need water, but also need oxygen in soil to grow well.  You can add iron, but the only formulation that works where plant can absorb is chelated iron, or sometimes called iron chelate. An application of an EDDHA chelated iron, such as Sequestrene 138 Fe may help  It's more expensive and something that you'll need to add every year at this site.

The added root microorganism, mychorrizhae fungus, in most studies have been shown to have not beneficial effect.

Posted on 1 Jun 2009

Maggie Shao
Horticulture Agent, Salt Lake County

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