Plant Propagation, Part III
For my last column in this series on plant propagation, I thought I would cover some of the more challenging methods of this art: grafting, budding, and tissue culture.
Grafting involves joining separate plant parts together to form one plant. There are two parts to the graft. The first part is the scion, which is the part at the top of the graft. This is the cultivar that you are interested in propagating, and will bear flowers and fruit.
The second part of the graft is the rootstock. Rootstocks are often chosen for their disease resistance and/or size control. Fruit tree rootstocks show a wide range of size control options, from dwarfs to semi-dwarfs to almost full size trees. A good example of rootstocks used for disease control occurs in vegetables, where plants with resistance to soil-borne diseases can be selected to serve as rootstocks for a cultivar that is susceptible to a particular disease that may be infesting your soil.
Yes, there is science behind grafting, but it is also an art, where it takes a lot of practice to find success. There are many different types of grafts, and if you would like to try your hand at making a graft, get a good book on the topic.
Budding is similar to grafting, except you are removing a single bud from the cultivar you wish to propagate, and placing it on another plant, which will eventually serve as the new plant’s rootstock.
There are basically three methods of budding: T-Budding, Chip Budding, and Patch or Shield Budding. Like regular grafting, some skill in the art of carving wood is needed.
The trick for grafting and budding is the ability to match up cambium layers so that they will grow together properly. The cambium is the part of the plant that is forming new cells… xylem to the interior of the plant and phloem to the outside. If this is not done properly, the graft will fail. I should also mention that keeping everything clean is critical. You do not want to introduce a pathogen into your graft.
Tissue culture is the final method of plant propagation that I will mention. This falls in the category of “Don’t try this at home”, at least in my opinion. This requires surgically-clean conditions and special lab techniques. Commercial labs can do a great job with tissue culture, providing disease-free plants if the right techniques are followed.
I will close with another precaution. Be sure that it is legal to propagate the plant that you are interested in. There are two laws regulating this area.
The Plant Patent Law protects vegetatively propagated plants. This law was enacted to protect plant breeding programs and encourage the development of new cultivars. Patent holders have legal right to control reproduction, and thus you are not allowed to propagate these cultivars, even for home use. The Plant Variety Protection Act is similar, protecting seed-propagated cultivars.
University of Missouri Extension programs are open to all