A few nitpicks. Lileep has 4 weaknesses, Ice, Fighting, Bug, and Steel. Of the 4, only 2 really matter, Ice and fighting. Ice because it gives the flower a tougher time switching into water types who often carry ice type moves and fighting because it is so popular in the tier. I think giga drain deserves an honourable mention in a bulky hard-hitter set here:
EVs: 188 sp. atk, 220 sp. def, 100 spd
Modest (+sp. atk, -atk)
Earth power/Ancient power
Hidden power fire
If lileep comes in on a water attack, lileep has its special attack boosted to a tasty 24 and can set up a substitute with ease as it switches. Giga drain gives some good restoration. Hidden power fire hits ferroseed and bronzor hard(ish in the latter case). Earth power hits a bit harder than ancient power but ancient power can hit flying types like taillow.
And what about some info on team-mates and counters. A little more thorough would be good.
And btw, in your signature, drilbur isn't broken ;)