Remember, treant is strong and do much dmg early. Use grasp to take away the possibility for enemy in safelane to farm, if he cross it you go out and chase him down to tower, hit him if you have the chance and then go back in lane and in the woods.

Get shard as soon as possible, its very good to be able to root your enemy with a hit and then use ulti.
Blink is good for treant but not the key, and Vlad is really good if you have a strong melee carry in your team.

always keep an eye time to time to see if your teammates are in a fight or getting chased. if so, you just use your heal on the
profile hero picture and heal him, instead of looking him up on the map.

trust your teammate, becuase 7 times of 10 they will know what to do and you just jump in and make sure he gets what she/he want.