The veterans on this site will begin by asking where you are (general location and plant hardiness zone). Two years ago, I bought and planted about 25 low-growing junipers (not Blue Star, but spreading, similar), and noticed that winter causes them to change color to brownish-blackish at the tips. Yours does not look like that's the only problem though. These look a bit like they started winter out a bit on the dry side, and had some winter kill. You might try a bit of fertilizer for acid-loving plants, such as Hollytone (anything for conifers, azaleas, rhododendrons, blueberries, etc.). And you might check to see if the Blue Star is trying hard to grow in alkaline soil (if so, it will likely always look a little peaky). It should drop those dried up needles and green up as the growing season begins. More information would be helpful-how long has it been there, what kind of light does it get?