How can I generate rootstock for stepovers?

[bazzaboy]

I’ve been trying my hand at some apple grafting with rootstock from Blackmoors (M27 dwarfing and MM106 semi-vigorous). I’d like to generate some more for next year (partic the M27 for creating stepovers) but not sure how to do it. I’ve planted a couple of each type at standard depth in their own space of about a square metre. Once they’ve settled do I then mound soil up the stem to generate more stems with roots and then harvest the results when dormant next winter? And then repeat the process? Is that how it’s done?

Or just buy more from Blackmoors and get out more?

Looking ahead to the stepovers there seems to be two ways of doing it, a) train the main stem (whip? maiden?) through a 90 degree turn and then plant a number in a sequence nose to tail
(r r r r )
or b) create in effect a single-tier espalier and plant as a series of T’s
(T T T T).
Is one technique preferable?

[FB.]

M27 rootstock is very slow-growing, so it could take several years to turn one piece into a multi-stemmed stoolbed, followed by additional years of grafting and growing-up the maiden trees, followed by planting-out in their final locations and then training.

For the cost of £2-3 per rootstock, I'd just buy more now (or buy some ready-grown apples on M27).

The "T" shape is preferable as a one-sided plant will tend to lean unless well-supported.

[bazzaboy]

M27 rootstock is very slow-growing.....

Thanks FB, sound advice as always which I will follow "to the T". bb.

[boundtothesoil]

I’ve planted a couple of each type at standard depth in their own space of about a square metre. Once they’ve settled do I then mound soil up the stem to generate more stems with roots and then harvest the results when dormant next winter? And then repeat the process? Is that how it’s done?

I agree with FB about M27 being too slow to bother with (not that I've ever tried it), but MM106 may be a different matter (although you'd probably not use it for stepovers).
I planted a single MM106 and a single M26 a couple of years ago with the intention of startng a mini-stool bed, managing them pretty much as you say. At the end of their first year (Dec 2011), I harvested 2 MM106 and 1 M26 rooted stocks (at least 9 inches length). At the end of their second year (Dec 2012), I harvested 9 MM106 and 1 M26 rooted stocks. Although this is hardly a definitive trial, I've concluded that MM106 seems to like my heavyish wet soil and west Wales climate, whilst M26 is more reluctant. Hence, I'm going to expand the MM106 bed, but probably not the M26 one.

Although these new home-grown stocks (and bought in ones from Blackmoors) have been sufficiently well rooted to be grafted successfully within 2-3 months of harvesting/buying them, like most people I guess, I've found that the first season's scion growth is much better if I leave the stocks to establish really good root systems for a full year before grafting.

[orangepippin]

Although these new home-grown stocks (and bought in ones from Blackmoors) have been sufficiently well rooted to be grafted successfully within 2-3 months of harvesting/buying them, like most people I guess, I've found that the first season's scion growth is much better if I leave the stocks to establish really good root systems for a full year before grafting.

A variation on this approach is to plant commercially-grown M27 rootstocks, and graft (or bud-graft) in situ. In other words plant the rootstocks where the final trees are intended to be. The downside is if the graft doesn't take you have a bit of a problem, but the upside is you will get much better growth in the second season because there is no transplant shock.

[FB.]

Also consider growing a stronger rootstock (e.g. M26) which, being twice the vigour of M27 will be twice as quick to multiply-up than M27.
Then graft the M26's with weaker-growing varieties. Or dwarf them by not feeding or watering much.....or dwarf them by giving them a less fertile spot......or growing grass up to their trunk to half-starve them and reduce their vigour accordingly.