lawnmower parent
n. A parent who tries to smooth his or her children's paths through life by solving their problems for them.
Examples
2011
Director Prof Alan Hayes said lawnmower parents had taken up where so-called "helicopter" parents left off.

"Instead of hovering over their children closely monitoring them as helicopter parents are said to, lawnmower parents get out in front of their children to try and clear the way for them," he told the Herald Sun.
—Elissa Doherty, “Lawnmower parents cut confidence,” Herald Sun, April 14, 2011
2010
Some parents have taken the advice to such an extreme that they're hesitant to impose any consequences at all on their children. These include the helicopter parents who monitor their children's every move and the lawnmower parents who mow down any obstacle in their children's path.
—Mollie Ziegler Hemingway, “Spare the Spanking, Spoil the Report Card?,” The Wall Street Journal, January 21, 2010
2006 (earliest)
Many housing staff members and experts say parents are calling residential assistants and college administrators about roommates who stay up late and leave clothes in the middle of the floor.

"The parents are calling and they are trying to solve their kids problem, they are beyond helicopter parents (parents who are closely involved in their children's college life, but from afar) they are lawnmower parents," Cohen said.
—Eugene Scott, “How to deal,” The Arizona Republic, September 05, 2006
Notes
A similar phrase is curling parent, a parent who, like a sweeper in curling, clears away any obstacles that might cause problems for his or her children. The phrase was coined by the Danish psychologist Bent Hougaard in his 2004 book Curlingföräldrar och Servicebarn [Curling Parents and Service Children].