Casting speed and Vine

Some said Casting speed can increase the speed the two Plant/Vine skills. Is this true? I tried with one support gem with casting speed but I am not seeing much difference. Maybe I am not high enough?

In the case of Entangle, it's the fissure that seems to do damage, so casting it faster should allow for higher damage per second while you keep casting.

In the case of Thrashing Vines, it says « 2 vines grow per cast time », and « vines grow for 8 second duration », so a faster cast time (base 1s) should also allow more vines to pop up during that duration (and you don't need to keep casting).

Oh so it does matter for Thrashing Vines. Thanks.

But one other thing. I saw some Plant builds and none of them take Overabundance for one more Limit. Why is that?

I can see when I cast twice, I see more Thrashing Vines. Is it because a target cannot be hit by Vine more than once 0.5s?

Good question, because when testing I did see more vine growth too, as well as higher single target DPS... but perhaps because my own cast speed isn't particularly high (0.86s), while this effect falls off at higher cast speeds ?