Grafting Tree Peonies

I'm going to do a workshop on grafting tree peonies for the Meneice Conference next October.  I've done my research, and I had intended to get with the program, but other work got in the way and I was delayed to mid November, a few weeks later than what is recommended.

Here you see roots of the herbaceous peony 'Jan van Leeuwen' and scions of various tree peony cultivars.  In the upper right hand corner are finished grafts.

Scion wood consists of terminal stems with strong lateral buds.  I removed the bud at the top since it contains the flower, and flowers, if allowed to develop, slow the regeneration process.

It's not the most perfect cut int he world, and I know the bottom is ragged.  The key part is that the slant is even, and you can clearly see the cambium, which is a sharp green line between lighter phloem and xylem.

Next, I tried to cut a matching wedge out of the top of the herbaceous peony root.  The roots have tough fibers, so this is not as easy as cutting a wedge out of a carrot!

Then the scion goes into the root, and I matched up the cambium layer as best I could.  The scions are much smaller than the roots, but I only need to match up one side for a successful graft.

Finally, a strip of rubber holds it all together.  Then a piece of wax film to keep the graft from desiccating.  I put half of them in a warm environment to promote callus growth, and half I kept in refrigeration, since I found reference to both methods on various Internet sites.  The ones kept in the warm treatment have been planted in the ground; those in refrigeration will remain there until spring, when they will be planted out.  They must be planted very deeply, with the scion completely buried, to encourage the tree peony scion to form its own roots.  I didn't know this until my research, but the herbaceous peony root should be removed after the tree peony scion grows roots or the tree peony won't thrive, and herbaceous peony shoots can overwhelm the tree peony.