If you can graft it to the tree you may be on to somthing but inter genetic grafting can be difficult. Peyote grows will tell you that grafting peyote on other faster growing cacti makes them flower in a year as opposed to 4.5. Plants can flower at any size just depends how much nugs you want per plant. You could use a one gallon sure it may dry quickly though and difficult to water every couple of days.

Disguising it with sticks and hay or grasses should work the issue would be securing it so when it storms so it stays in the tree.

If it grafted to the tree and used it as a water source that would be amazing.

You may have to drill into a fresh branch, a decent size hole, and fill it with the proper medium. The open wound may be prone to infection so a medium consisting of coco fiber in part which contains calcium will help. Imagine drilling holes into tree truncks and putting in little plants that grew super fast and finished early. Most trees produce bio-chemicals earlier then cannabis which is why they lose there leaves when your outdoor is still green. I wonder if there are bio-chemicals you could feed plants to shorten harvest time for outdoor. Very intreging.

I dig the new ideas to the forum, I think you may be on to something here.

Just think a tree truck of cannabis. A problem to harvest put a site to behold.

One love
c