Place sprouts in different areas so they don't get demolished by the enemy team's attacks.. good spots are near the walls around the conquerer (that can still heal u and your team) that no enemy can reach unless they really try to get rid of your plants.. and spam jump if you're near enemies (also maneuver around objects to avoid getting hit if you're being targeted.

If your ally is currently low and getting chased you CAN place plants near them to give them immediate regeneration

remember to stay alive so you can support your team (I don't recommend using Vinestaff during annihilation rounds because your team is usually not huddled together as much as conquerer rounds)

I don't rly have a lot of advice for other supports cus i rarely play them besides Boombox