A variable length support rod apparatus for translational support of a window treatment, such as draperies, comprised of a support member formed of a plurality of transnationally engaged segments, the support member is infinitely configurable from a minimum contracted length to a maximum extended length through a translation of the plurality of segments toward or away from each other. A continuous flexible member is positioned along a pathway running between a first end and a second end of the support member. The support rod may be configured to any length between the minimum and maximum lengths and may be fixed to a support surface without an adjustment of the fixed length of the continuous flexible member.