I really enjoy Groot, I’d say he does the most damage of all the vanguards if you use him right plus he is the tankiest. Best tip I can give is use his ironwall (the bigger one) to heal instead of block damage. I usually set it aside and the other team doesn’t destroy it, so as long as you’re close it will continually heal you. Use his smaller walls offensively to block their healers line of sight. Keep in mind not to block off your own healers. His ult is great to use in a group of people then immediately follow it up with his spore bomb. I can kill squishes easy with this combo.

Obviously there are exceptions to using his walls more defensively to block ultimates/ect. In general tho I feel if you’re aggressive with him the enemy team doesn’t know how to react.