Pawpaw Leaf Problems: Follow-up

Last month, in an entry titled "Asimina triloba: Leaf Problems," I wrote about how the leaves of two of our pawpaws (the Wells and the Shenandoah) were curling and I didn't know why. I emailed with Sheri Crabtree (Horticulture Research and Extension Associate at Kentucky State University), and she suggested it could be a calcium deficiency and recommended we give the pawpaws some fertilizer with calcium. So I did,

But after I did, I realized I wouldn't really know whether the fertilizer was helping (or if anything else was helping), since the branches seemed to have already reached their terminal leaf buds for the year. So it seemed like there wouldn't be any new growth until next spring. I also realized that even if the fertilizer was helping, I still couldn't expect the leaves that had already grown in a curled way to begin uncurling. The only cure for those leaves would be to fall off the tree and decompose.

So, how to measure whether anything was having an effect? Fortunately, I was able to find a few branches that hadn't already reached their terminal leaf buds for the year at the time I put the fertilizer on. And the one or two leaves that grew after the fertilizer application seemed to grow without the curl. (But honestly, I don't know if it was the fertilizer that did the trick or if it was that some unknown stressor in the pawpaws' environment that disappeared.)

But in spite of all my ignorance, here are some pictures with good results. 

Here's a branch with very clear leaf problems in its July leaves; but look a little higher to the August leaves and see that they developed without the curl.

Look at that edge--a scalpel's edge almost.

I've got to admit, it's getting better.