But there was likely a more straightforward answer: the saplings weren't crabapples at all. They are Pyrus calleryana (Callery Pear), a tree that is more common in suburban landscapes than it rightfully should be. Dirr has described this tree's spread as reaching "epidemic proportions." Better known by their popular cultivar names 'Aristocrat' or 'Bradford', these trees are best known for their prolific displays of white flowers (and their accompanying less than pleasant odor) in the spring. In our town, the blooming of the pears is as much a harbinger of spring as tulips, daffodils and forsythia.
In autumn, their glossy leaves turn deep, fiery oranges and reds, accompanied by a profusion of quarter-inch diameter fruit, a favorite food of local birds.
And herein lies the problem...the birds. What goes in, must come out. The bird droppings contain the seeds of the pear tree and are deposited, well, wherever it's convenient for the bird. And so the neighborhood ends up with pear saplings sprouting up in the most random places. I've found them growing in driveway cracks, in the lawn, and -- of course-- throughout our garden beds and borders.
What's the big deal, you might ask. Just pull them out. Therein lies the problem. The occasional digestively-transported sapling wouldn't be troublesome, except that this particular tree has an incredibly resilient tap root that seems to grow as far below the soil as the sapling grows above.
The two photos above show just part of the tap root on two saplings I dug out this morning. On the larger sapling, I dug out at least eight inches down and still could not pull out the sapling with bare hands. I ended up severing the tap root with a spade.
Aside from it's tendency to be weedy, the Callery Pears also are known to be weak trees as they age, forming very tight branch crotches that break easily in windstorms, common here in the Midwest. In fact, our neighbor to the north lost their Callery Pear a few years ago in heavy winds. As you can see in the photo below, it was a resilient tree. They did not remove the stump of the damaged tree, and now they may have the only known Callery Pear shrub in town.
Is the Callery Pear going to stop reseeding itself into my yard any time soon? Probably not. There are literally hundreds of these trees planted in the 1/2 square mile that is our subdivision. They'll keep brightening the streets in the spring, feeding our birds in the fall, and, yes, spreading their seed wherever they can.
I guess I'll just need to keep a keen eye and a sharp spade at the ready.