You need to remove the growth from the rootstock if you want to keep the Butterflies strong. The M stellata will be more vigorous and will outstrip the cultivar.

on grafted plants.... in general .. the root plants are more aggressive ... hence one reason to use them ... as root stock ...

but.. if they are allowed to live ... they can basically out compete.. and end up killing the favored.. weaker plant ... if by not other means.. than out growing it.. and shading it out ...

the converse is.. the foo foo ones are more expensive.. because they are inherently weaker ... one way of another ... if no other way.. in that they are more costly.. or harder to propagate ... etc ...

properly prune them off ... and then go to big box.. and buy a cheap star magnolia ... think of it this way.. you might threaten a $50 plant.. to get a 10$ plant ...

ken

ps: welcome to the forums.. there is a shrub forum .... if you are interested ...

That’s what I figured! Thanks

you are welcome.. when you get down to the old cost/benefit ratio ... you usually can figure the answer out ...

do you know how to properly prune? .. if not.. start a new post in the shrub forum ...

ken