Dr. Roston's new propagation technique was purely the result of an accident. He was dividing a hosta and like we've all done at one time or another, the division broke off above the crown. So he tossed it away. Several weeks later he was back at the potting bench again to divide another hosta. He sat a bucket down and then realized he'd set it on something. When he moved the bucket, the hosta he'd broken off and thrown on the ground earlier had landed in a spot where there was a constant drip of moisture. And to his amazement it had sprouted a good set of roots in just a couple of weeks time. Not in soil but constantly moist.
So he began experimenting and discovered that if a cut is made anywhere from just above the crown up to an inch or 2 on the stem, that if it's stuck into sphagnum moss or a soilless growing mix and kept moist that he would soon have a new plant. He also suggested dipping it in Rootone to speed up the process.
He had one Royal Standard plant that he estimated he got 500 plants from over 3 years. He'd taken 'cuttings' from it using this process 2 or 3 times a year. After the 3rd year the original plant was finally 'burned out' and died.
Also after the stem is removed above the crown, new eyes form around the crown and the crown can then be divided vertically to produce new plants.
Another slightly different form of increase was also the result of an accident. In the fall he had planted hostas in a new area. They were dormant or mostly dormant when his son dumped a large load of compost on the area without knowing that it was planted. The compost was finished 'cooking' & was 12-18" thick. In the spring he checked on his hostas and to his amazement [he didn't know the compost had been dumped there], the plants were sending up vertical 'stems' to just below the surface of the compost where a new plant would form. And he was able to cut those vertical stems into pieces 1 1/2" - 2" long, plant them and start new plants. And also had a new plant at the surface of the compost plus the original plant.
Goes without saying that I'll give this a try this year. I'll have pictures and will post them here. I have coined a new word for the technique: Rostonizing, after the good Dr. who discovered it.
The first leaves getting the treatment are a couple 'So Sweet' leaves, shown here dipped in rooting hormone.
Here they are potted in a soilless medium, Promix BX. The wire basket hangers serve as a frame work to hold the plastic bag in place to maintain humidity and deal with transpiration. This was done June 16th, 2007.
The only bags I could find that were anywhere near big enough were some bread bags and even then they were not quite long enough, so I ended up putting two of them together with some tape to get something long enough to go over the wire frame and keep the bag off the leaves. Looks pretty weird, but it's very effective. The bags nicely stretched around the perimeter of the pot to provide a good seal.
The largest of the three 'Revolution' plants we have was getting a little too big for the spot it occupied, plus it was starting to develop an all green leaf. So, time to lift and divide. With the size of the plant it was unavoidable that some leaves would pay the price. Of these three you see here the one on the far left was broken off right at the crown, the other two higher up. All three were dipped in rooting hormone and planted in Promix BX, a soilless medium, and for good measure the far left one was 'bagged' to aid with transpiration. This was all done on June 24th and after 30 days or so we'll see how well we did in terms of developing roots on these leaves.
On July 16th curiosity got the better of me and seeing as it now is one month after I first did the two 'So Sweet' leaves, I took one of them to see if there was any evidence as yet of hints of root growth and I'm sad to say there wasn't any as yet. The bread bags certainly helped with the transpiration as the leaf was still nice and firm, the growing medium was nice and moist, there were no signs of mildew, but there was also no sign of root development. So, let's give it another month, even though supposedly root development should start within about 2-3 weeks. Guess I'm not holding out much hope.
The three 'Revolution' leaves were a definite bust. There was only one that was given a bread baggie and it must have been a particularly dirty bag because the leaf mildewed and the other two had too much water loss without any protection and they simply ended up as part of the compost.
On August 11th I just HAD to find out what was happening with the second 'So Sweet' leaf and sure enough, there were 2 roots developing!
Root development happened over an 8 week period. I also noticed the leaf was going into senescence and it will be interesting to see how this will effect the 2 small roots on this petiole.
I would at this point call the experiment a minor success. And it's not over yet of course. Next spring will really tell the story, whether or not we'll see a new shoot develop from these 2 little roots. Stay tuned. My gut feeling though with this little trial I did is that if I want more predictable results I should stick with Rossizing or plain old-fashioned division and that's what I'll stick to for the 2008 season.