Espeon already has okay-ish Special Defense, but poor HP and horrible Defense. It is meant to be an offensive Pokemon, so Choice Specs works better.
After all, it can't take STAB Super effective hits from the likes of M-Gengar anyway.
Tl;dr: Try Choiced items. Special Defense boost won't last all that long.
Also, try another move other than Grass Knot. Signal Beams works, but you might also want to consider something else like a decent typed Hidden Power, if you can.