Grafting

Today reminded us that winter is not really over, even though it really seems like we haven't had a winter.  I think us garden folk are feeling a bit guilty about this, but I remind gardening friends of the horrible winter of 2009-2010, and we tend to agree that we are due this mild winter.

I worked on grafting some maples today.  I have to digress and let you know that until last year, I was convinced that I had no ability to graft anything.  I attempted to graft apples in a Plant Propagation class at the University of Minnesota, and I think all four of them promptly died, even though I tried to cut the scion and rootstock with surgical precision.  We had a grafting inservice training for staff in 2010, and I tried to graft some gingkos and lacebark pine.  The ginkgos took, the pines did not.  I quickly found out that everyone's gingkos were successful.  Apparently, they are very forgiving.  I tried to graft some limber pine from a small disjunct population near Mount Rushmore in South Dakota, but those failed too.  Then I finally met success with Algerian fir.

This is Algerian fir, Abies numidica.  Firs don't generally do well in Washington, DC, but this one has been vigorous and healthy for the twenty years I have known it.  I think it was planted shortly after I started at the U.S. National Arboretum, and I have enjoyed watching it grow.  At any rate, I grafted about twenty scions from this tree on Abies nordmanniana rootstock, and I was shocked when the buds on the scions began to grow, signalling success.  Here are the resulting plants:

How did I achieve success?  I think it was a change in aftercare methods.  Our prior attempts put the grafted plants in a humidity tent in the greenhouse to recover and heal.  I think the clear plastic of the tent just kept the temperatures too warm, and heat is not conducive to post-graft healing.  We changed to a method of piling some damp sphagnum around the young grafts, and this seemed to work much better for the firs, at least.  I've been grafting some pines and spruces with this methodology:

The tiny scions are basically buried in the wet spaghnum.  The pots are on their sides to keep the spaghnum in place.  Here's what's under the sphagnum:

Now I'm grafting Japanese maples, and waxing the graft union rather than using the sphagnum.  Hopefully some will be successful.