Growing Together. The following numbers increase by 1 when your proficiency bonus increases by 1: the cultivar's skill and saving throw bonuses (above), the bonuses to hit and damage of its slam attack, and the DC of its Root action (below).
Slam. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4 + 2) bludgeoning damage. The cultivar can then use a bonus action to attempt to grapple the target. Root. The cultivar extends its roots toward a Large or smaller creature it can see within 30 feet of itself. The target creature makes a DC 13 Strength saving throw. On a failure, the target takes 1d6+2 bludgeoning damage and is pulled up to 10 feet closer to the cultivar.