I posted this in the conifers discussion, but it may apply in all things gardening. Most JM are grafted in Acer palmatum Red or Green rootstock right. So the same rootstock is used on a medium or large JM and even -Dwarfs- Is there a symbiotic relationship on how much or how large the roots will grow relative to what the cultivar it is mated to. ----- I have a conifer. It is very slow growing. Like 1-3 inches Per Year. I just repotted it and was amazed on the root development. Granted it' gotten a decent rootball since the time of planting, the overall rootball H was about 8 inches or so. I am thinking it's relative due to the fact that the cultivar that is mated to is slow growing. ----- With that said, I don't think it may or may not apply to JM. Semi Dwarf Japanese Princess, seems to have filled out a 15G pot in depth and width in just 2 seasons
It used to be that red was grafted on red, the concept being the reds were more vibrant. That doesn't make much sense genetically, but in any case, it is almost never true now. Anything in Sec Palmata is typically grafted onto A. palmatum. Seed grown. In China, they use A. elegantulum. Certain Iseli "hardy" cultivars should be grafted on pseudosiboldianum, though in Europe this isn't the case: that rootstock is unavailable. So those cultivars aren't any hardier, here, than A. palmatum. Here's the dirty secret of JM production. Rootstock is more or less vigorous, puts on more or less root, is more or less healthy. It is grafted randomly with no particular attention to it's characteristics. If I have 10,000 bare root understock, and I need to make 1,000 Bloodgoods, I crank them out. Boom, liners. Some will grow fast, some slow, some get bigger than others. Same with dwarf(ing) cultivars. Put a Pixie on very vigorous understock, you may have a pretty big tree quite soon. Will it grow as big as Bloodgood on the same roots? No, but it might get bigger than you expect. And Bloodgood on dwarfing rootstock will potentially never grow as big as expected. It's not like apple understock, where you graft onto a clone with known size properties, dwarfing, what have you. So you always have a predictable tree. Of course there are lots of other cultural factors, so the above is an oversimplification. Anyway, if the roots are in good shape on your plant, it's doing well, so that's the main thing.
Thanks for the Wiki emery. I haven't taken a deep dive but what rootstock is commonly on pictums. The pictum I have....I know it's not acer palm as it's just appears different. Haven't had a chance to deep dive on that queastion I was thinking about.
pictum is in Sec Platanoidae. Those are all the maples with white latex sap, and they can only be grafted within the Section. A. pictum is usually grafted on A. truncatum in the west. Further though, you can only graft (successfully over the long term) Platanoidae which has the same wood characteristics during the second year: green or brown. For example, cappadocicum is green, but pictum is brown. So you although you could graft pictum on cappadocicum, it would probably be nonviable in the long term. Because Sec Platanoidae bleeds so freely, you can only do winter grafting over a few days, when the sap is down. Someone was just telling me about a recent conversation with Japanese grafters working on pictum, they can only graft during a few days. But because of climate change, those days are moving, and it is a challenge to determine when the right period is. Of course, if you have plenty of pictum, you would graft those cultivars on pictum understock.
