The rotary cultivator enables an operator to cultivate an area immediately adjacent to (for example) perennial plants. The cultivator is a tractor-mounted tool with an articulated boom. A rotary cultivator head is disposed at a distal end of the boom so that a tractor operator can manipulate the boom and attached cultivator head through a full range of motions. The cultivator head includes a rotary disk with two essentially identical blade assemblies. Each blade assembly has a short blade that rotates within the periphery of the disk, and a long blade that extends beyond the periphery of the disk. The long blade has an extended segment that is flexible and elastic so that when the long blade extended segment contacts the stalk/trunk of a perennial plant, the extended segment elastically deforms so that the stalk/trunk is not damaged.