The Whomping Willow is a very valuable, very violent species of magical plant. Whomping Willows attack anyone and anything that comes within range of its branches. A deciduous plant, its limbs function as arms and any damage to them must be treated in much the same way.
Known Whomping Willows
The Hogwarts Whomping Willow
The most famous Whomping Willow is the one planted on the grounds of Hogwarts. The Whomping Willow was planted around the year 1971 to disguise the opening of a secret passage leading from the Hogwarts grounds to the Shrieking Shack in the village of Hogsmeade.
The Oshawa Whomping Willow
Perched overlooking Lake Ontario, just south of the waterfront trail, this thorny willow has calmed in its later years. You'll typically only see it move when agitated by strong winds. It also likes to tangle itself in the clothes and hair of anyone who ventures near.
Congratulations to HOWsMom for the speedy FTF!