This past autumn, I noticed a sucker growing from the base of the Serviceberry (Amelanchier arborea) in our backyard border. There was a single leaf perched at the top of the shoot, and it looked decidedly unlike Serviceberry foliage. I vaguely remembered the previous owner of the property (who had planted the tree) mentioning that it was grafted to a rootstock of some other genus.
Amelanchier is relatively easy to graft, so easy that it will often graft successfully to other genus in the Rose family . Judging by the thorns spiraled up the length of the sucker and the shape of the leaf, I'd say the root stock belonged to a Crataegus (Hawthorn) species.
How do I know this is a sucker of the Serviceberry, rather than a random Hawthorne seedling growing next to the Serviceberry?
You can tell a shoot is a true sucker by lifting away some of the soil or mulch from the trunk to see where the shoot is attached. In my case, the Hawthorne shoot is certainly growing out of the Serviceberry root stock.
Perhaps it's the plant geek in me, but I'm tempted to see what develops from this shoot. Could I actually grow an intertwined Hawthorne and Serviceberry? But I should probably remove the sucker. As Laura Hayden (from Durable Gardening) reminded me, the rootstock is likely giving the Hawthorn sucker preference over the established Serviceberry. The longer the sucker stays, the less vigor the Serviceberry will have.
While it looks like the local bunnies have already started to nibble the bark, I think I'll make a visit to the back border and introduce the sucker to the friendly Mr. Felco.