This build is centered around Grover's dr card, Unstoppable, which gives you 30%dr for 4s after Blossom, which is also at 5 so you can have as much dr up as possible. Rebound at 3 to give you that extra sustain, and Barkskin and Force of Nature as fillers to provide a bit more tankiness. You run Rampant Blooming so you can still provide healing to your team.

Unstoppable
Blossom
Reduce your damage taken by 30% for 4s after using Blossom.
Level 5

Perennial
Blossom
Reduce the Cooldown of Blossom by 2s.
Level 5

Rebound
Armor
Increase your Healing received by 15% while at or below 50% Health.
Level 3

Force of Nature
Armor
Gain a 150-Health Shield for 3s after dropping to or below 50% Health.
Level 1

Barkskin
Armor
Increase your maximum Health by 75.
Level 1

Rampant Blooming
Vine
Heal for a burst of 500 and an additional 300 over 2s in a 50 unit radius at your location when you finish Vining. Curative (+20% Healing)
Level 1

Chronos
Armor
Reduce the Cooldown of all your abilities by 10%.
Level 1

Morale Boost
Armor
Increase your Ultimate charge rate by 10%.
Level 1

Rejuvenate
Armor
Receive 10% more Healing from other players.
Level 1

Guardian
Armor
Increase the effectiveness of Shields you create by 10%. This does not affect most cards and passives.
Level 1

Haven
Armor
Reduce the Damage you take from Direct and Area of Effect attacks by 6%.
Level 1

Nimble
Armor
Gain 7% Movement Speed.
Level 1
