I seem to be virtually skimming the hedge at the end of one of our runways when I t/o using full flap!)
And then you probably haven't flown the aircraft anywhere near MTOW yet. (Unless you're flying a 152...)
Pilot DAR knows chapter and verse on this, but I think the certification requirement is that the aircraft is able to climb at at least 100 ft/min with full flaps and at MTOW. But that's in ISA conditions at 0' DA. On a warm day and a slightly elevated airfield you might not be able to climb over the hedge at all.
If the POH doesn't include performance data for a full-flaps take-off, then that's probably because it doesn't give you the best take-off performance.