Gallatin Planted Them All at Once, Twice
Drive the late-1980s streets off Hartsville Pike in April and you can date the subdivision from the car. Near-identical white-flowering pears went into the front yard of practically every house built between 1988 and 1991, and a second wave went into the 2006 to 2012 phases further out. They were cheap, they were fast, they flowered on schedule, and nobody knew yet what they would do at thirty-five years old.
What they do is split. The classic callery pear failure is a narrow V crotch with included bark that finally lets go in a storm, usually taking half the crown with it, and that is why so many of them came out in one week after a single line of weather.
Which leaves a street full of pear stumps, all the same age, all with the same problem underneath them.
The Root Plate Is Wider Than Any Grind
A thirty-year callery pear has a shallow, wiry, dense root plate that can run eight to fourteen feet across on a tree with a trunk barely eighteen inches through. Those roots sit in the top foot of soil, and a great many of them carry dormant buds.
A standard grind takes the stump, the flare, and lateral root out to somewhere between eighteen and twenty-four inches past the trunk. That is entirely adequate for an oak, which will not come back. On a pear it leaves several feet of live root in every direction, and any piece of that with a viable bud can push a shoot once the shade and the hormonal signal from the crown are gone.
There is a second wrinkle specific to this species. Ornamental pears are grafted, so the roots are a different plant from the tree you looked at. When rootstock suckers come up they are frequently thorny, they grow with a wild upright habit, and they are the plants that go on to seed wild callery pear into fencerows. Whatever you liked about the original tree is not in the part that survived.
How We Grind a Pear Differently
Wider and shallower. Rather than concentrating on depth under the trunk, we chase the surface runners outward, taking the plate apart where it is close enough to the surface to reach, and we take the flare down further than turf strictly requires so there is no collar left to sprout from.
That is more machine time than a maple of the same diameter, and we say so in the quote rather than quietly doing less work for the same money. It also produces more chip volume than people expect, because a lot of what comes out is root rather than trunk.
What a grinder cannot do is treat the stump chemically. Cut-stump herbicide works when it is painted onto living cambium within minutes of the tree being felled, which means it is a job for whoever takes the tree down, not for somebody arriving three weeks later. If a tree crew is coming out and you know the pear is a sucker risk, that is the conversation to have with them on the day.
If Suckers Come Up Anyway
Sometimes they do, and mostly in the first spring after removal. Pulling them by hand is better than cutting them: a shoot snapped off at ground level regrows from the same point, whereas one pulled with a bit of root attached takes the bud with it.
Repeated mowing across the area will exhaust most of them over a season, because every shoot the plant sends up costs stored energy it can no longer replace without leaves. What does not work is ignoring them for two years and then dealing with a thicket of six-foot thorny stems.
If a sucker comes up inside the footprint we ground, within twelve months of the job, we come back and take it out. That is not a generous gesture, it is what grinding wide of the flare was supposed to prevent.
The short version
Callery pear regrows from dormant buds on a shallow root plate that can be three times wider than the grinding footprint, and because the trees are grafted, the suckers come back thorny and wild. Pear stumps need a wider, more aggressive grind than a hardwood of the same diameter, and any suckers that do appear should be pulled rather than cut.