The leaves are needle-like , mostly 2.5-5 cm long , occasionally up to 7 cm long , very thin ( 1 mm thick ) , borne singly on long shoots , and in dense clusters of 20-30 on short shoots ; their colors range from bright green to glaucous blue-green in color . The leaves are needle-like , mostly 2.5 â `` 5 cm long , occasionally up to 7 cm long , slender ( 1 mm thick ) , borne singly on long shoots , and in dense clusters of 20-30 on short shoots ; they vary from bright green to glaucous blue-green in color .