Propagation & Grafting
For growers and would-be growers of rare and borderline plants, learning to propagate them is often the key to success. Propagation provides you with multiple plants to experiment with, some of which you can put in various places in the garden, and some you can protect in a coldframe or greenhouse as backup plants.
Sometimes merely growing plants on in pots for a few years makes all the difference. Punnett used to plant everything out as first year seedlings or cuttings. He is now finding that some of the things he thought were impossible will survive once they get a bit of age on them.
Some plants are easy when young but grow difficult as they get older. In order to maintain them you must propagate them. Surprisingly, many gardeners don't have a clue about where to begin. Here's a clue: sticking cuttings in water is absolutely the worst method. Don't do it.
At one time or another, we have employed virtually every method there is. For the average home gardener we recommend the following:
Build a "Nearing frame." This is nothing more than a wood box about 1' deep and a few feet across sunk halfway in the ground with a clear polyethylene cover. On the south side, place a white sheet of plywood at a 45 degree angle to block any sunlight. On the east and west side, place triangles of white plywood. You want only reflected light to enter the frame so that you will not cook your cuttings.
Fill the frame with a mix of sphagnum peat and pearlite. 50-50 works fine; you can get fancy later. If you have a greenhouse, you can use the same box without the reflector in the winter when the light levels are lower. In this case, it's best to add a heat mat under the soil; bottom heat is a big help in winter.
Once you have your frame, you need to stick some cuttings. Don't select very soft new growth since it wilts and rots very easily. And old growth is often very slow to root. Find something in between. Learning exactly when to cut takes years of practice, but if you whack a few cuttings each week some are bound to root, and you will start to get an idea about what works.
Use a liquid hormone, either KIBA which is water based or Dip and Grow which is alcohol based. 1,000-5,000 ppm works for most things. Don't be afraid to experiment. Avoid the powders; they generally give results that are much more irregular.
There are many different types of cuttings, but in general, terminal shoots of moderate length cut just below a node work well. It's good practice to cut them a bit long and immediately toss them in a bucket of water just prior to sticking. Remove the lower leaves and trim with a razor blade just below the node. Hard to root things may benefit from a light wound. Slice off a very thin strip just up from the base. Dip in hormone for a few seconds then stick; it's also a good idea to water them in lightly with a dilute fungicide solution. In general, once moistened frames need little water. Overly soggy is very bad.
Many conifers can be cut in the fall and left in the Nearing frame for a year or two until they are well rooted. Deciduous material is best cut early summer. If it hasn't rooted by winter it's not likely to survive. Some hard to root plants do very well in a bottom heat frame in winter.
In general, fuzzy leaves are likely to be rot prone and should be removed from the frame as soon as possible. Bottom heat frames also work well for callusing grafts or for doing root cuttings.
Seed may also be germinated in cutting frames but we think other methods are usually superior.
(Some may wonder why are we telling you how to do this. The main reason is to help you be a more successful gardener, and besides if you already have a backup plant think of all the time you will save writing and calling us to get another!)
For those of you who wish to try your hand at grafting, here are a few basics:
Try to graft when the understock is well established and just starting to push new spring growth. Scions should always be more dormant than the understock.
Match sizes as best you can but always line up the cambium layers on at least one side.
Wrap with a rubber band or parafilm (a stretchy wax coated film that holds and waxes the graft simultaneously).
Aftercare is everything. Place the grafts in a closed frame or tent them with plastic until well callused. Be careful not to cook them or let them fungus up at this point. When callused, move to a protected place to grow on. We generally wait until the scion has pushed some growth before cutting back the understock, although we often cut it back just a bit to force lateral growth.