I purchased an upright Rosemary plant at a nursery approximately 3 months ago. About a month ago it suddenly shot up and sprouted numerous top branches, almost taking the shape of a Christmas tree. Ever since then its growth has halted.

I live in Palm Springs and the weather is regularly 90 degrees this time of year. The plant is at a western facing wall and receives 6+ hours of sun a day. It is watered every other day by a sprinkler.

I'm wondering if anyone could identify this behavior and what may be causing it. The plant is in an unflattering form and I would like to know how to best remedy it (i.e. encourage its growth into a fuller shape, or how to best prune it so to keep it upright).

I appreciate any feedback.

Jason

PS sorry for the rotated photo