Creating cork bark black pine

After doing some cutback on a corkbark black pine, I saved the clippings so I could do some grafting. Corkbark pines aren’t as strong on their own roots as they are on black pine roots. As a result, most of the corkbark bonsai we see are grafted. The earlier these trees are grafted, the better. At about 3 years old, young black pines can be used to host scions from corkbark pines.

3 year-old black pine seedling cutting

The first step is making room for the scion. I did this by removing the lower branches and needles.

After removing the lower growth

At this point I had a flashback to a pine I’d grafted many years ago. After performing a successful graft, I realized, several years later, that I’d attached the scion too high on the trunk. Before grafting this young pine, I removed the soil until I found the rootbase.

This pine was created by seedling-cutting. A few months after the tree sprouted, I clipped the taproot in the hopes of replacing it with many lateral roots. I was surprised, however, to find that only a single root had resulted. For the sake of the graft, I removed more and more soil until I found the spot where the roots began to divide. I prepared to attach the scion just above this point.

Only one new root

I prepared the scions by removing about half of their needles. The trick is to find the right balance – I want to keep as many needles as possible, but not so many that the scion will quickly dry out. In this case, I retained about five pairs.

Scion from corkbark black pine

After removing extra needles

I then cut the base of the scion to a sharp point and inserted it into the trunk of the seedling. The important bit here is lining up the cambium layer of the scion with that of the host. When the scion is thinner than the host, I try to line up the cambium on one side of the scion rather than centering the scion and missing on both sides. Both pictures below show the side that doesn’t line up well.

Scion in place

Another scion

After inserting the scion, I covered it with a plastic bag filled with a pinch of moist New Zealand sphagnum moss. I tied it all with grafting tape and moved on to the next seedling. The final step is covering the bags with tape to prevent the sun from drying out the scions.

All wrapped up

Back in the pot

Number two complete

Typically, pines are fairly active in January where I live as winters aren’t usually that cold. This year, however, has proved far cooler than normal, and within a few days there was lots of frost and the soil of my trees froze solid. This may have been too much for the scions, but I may not know for sure for several months. Fingers crossed!