Hi Lyn, let's try this again. My first attempt was nearly complete when I got timed out or something, losing it all....
1.. Can I use those laterals for wrapping next spring to create rootstock ?
Yes.
2.. How thick should they be to be most effective ?
At least as thick as the buds you wish to insert under their bark. They can be thicker than the budwood from which the buds were taken, but not thinner or there can't be solid cambium to cambium contact as the bud has to be bent to force it to fit.
3.. After they callus, do I grow the potential rootstock in a container for a season and then bud the next season ?
Yes, or not. Commercially, they're rooted in the ground this year and budded the next. If your stocks are growing vigorously the same year they are rooted, they can be budded the same year, but don't have to be.
4.. Would I be budding in the spring ?
You might. Commercially, most budding is done in June and July, but it can be done any time the stocks are growing vigorously, pushing a lot of new growth. Burling uses Pink Clouds and says it remains ready much of the year for her in Visalia. Hume seems to be fairly ready most of the summer, too.
5.. After I bud the rose, do I keep it in a container until the budding takes or plant it out into the garden ?
It can make it a lot easier leaving it in a can, as long as you don't let it dry out. One of the main causes of bud failure is extreme water stress. If you leave it in a container, if the bud fails, it's easier to re bud it in a pot where you can get it up on a table or bench and SEE it. Otherwise, it has to be done on your knees or sitting on the ground. Not fun.
You will have to remove all the growth buds but the two top ones before rooting the stocks. Missing one results in suckers. Leaving two top buds doubles your chances of success rooting them. If there is one and something happens to it, the cutting fails. Two gives you a second chance. You're going to bud below the top growth anyway, what's the harm in leaving more than one?
Here is a short Hume stock I rooted in January with the growth bud removed. I simply shave them off with a single edged razor blade, making sure I remove the two guard buds (one on either side of the main bud).
Here are longer whips, prepared the same way as the shorter stocks. White plastic garbage bags were cut into strips to wrap the above soil level lengths until they went from callused to rooted. White plastic allows light in so the green bark can photosynthesize food. The plastic prevents them from drying out until they are rooted. The top two remaining buds were not wrapped, but left out in the open where they broke into growth once the whips were rooted. Leaving the plastic on them now also helps to prevent them from sun burning in this extreme sun and heat. Some of these are Hume, others are a seedling of mine which refuses to flower (eight plus years and NEVER flowered), but it produces strong, straight, long canes which root incredibly easily. I will test it for standards using these whips. Being a seedling, there is an excellent chance there should be no Rose Mosaic Virus in them.
