Posted: 10/02/2014 at 12:09
If anyone's going to try this out, please do it properly and share the results with us.
You'll need a large sample size, so lots of cuttings taken from a single, large bush or lots from each of several large bushes.
You'll need to minimise variation in your sample, so take the cuttings at a standard length, take them all at the same time of day in the same weather at the same time of year and treat them all the same way, putting them all in the same compost in the same size pot in the same number of second after cutting and watering each with a standard amount of water.
If you're dipping in vitamin C solution or rooting hormone solution, dip the control group of cuttings in water the same way.
Look after them all the same way. This pretty much means filling the greenhouse with them in a chequer-board pattern so no group of cuttings accidentally gets a better part of the greenhouse.
Have a standard way of scoring "success" and stick to it. If you're taking 8" cuttings and putting them 4" deep in compost filled to the rims of the pots, having them grow to 5" above the pot rim may be a good criterion.
You'll need to gather data on how many cuttings have succeeded maybe every three days for quite a while to allow comparisons of the speed with which they took as well as the survival rate.
Finally, use something like a Chi-squared test to give us a probability that whatever variation was recorded was just random variation.