Q: I have a twenty-two-year-old Japanese maple with a bulge on the lower trunk. The tree is lovely, but it continuously puts out suckers in this bulging area. Is there any way to stop the suckers?
A: You are exactly right. The bulge is the original graft union on your maple. A twig with attractive leaves was grafted onto a vigorously growing maple seedling, making your beautiful tree. For some unknown reason the understock has started sprouting. These new limbs will never be very attractive. Try applying Bonide Sucker Punch (click for sources) to the bulge after cutting off all of the sprouts.