blueing of leaves? indication of strain perhaps?

many of my large fans and some smaller mid level leaves have turned blue. my plant has begun budding aprox 3 weeks ago, its about 4 feet tall 3 and a half feet wide. definatly indica dominant christmas tree like with very thick stem. dense skunky white buds so far. anyone seen a strain like this before?

Some strains look bluish but you should be on the lookout for other signs that there is something worng, just in case. If the leaves are cupped under or turn down at the tips, you may have a N overdose problem.