Casting Time: 1 bonus action
Duration: Concentration, up to 1 minute
At the very next time you do hit a creature with a weapon attack (it might be a melee weapon attack) before this spell ends, at the point of impact a writhing mass of thorny vines appears. Until the spell ends, the target must be succeeded on the strength saving throw or else be restrained by the magical vines. Basically, on this saving throw a large or the larger creature has an advantage. The vines will be shrivel away whenever the target succeeds on the save.
Whenever it may be but while restrained by this specific spell, the target will take 1d6 piercing damage at any of its starting of each turn. For making a Strength check against your spell save DC, a creature restrained either by the vines or else one which can touch a creature have a chance to use its action. Finally, on a success, the target will be freed.
At Higher Levels:
Whenever you cast this spell by using the spell slot of the 2nd level or higher than the 2nd level, the damage will be increased by 1d6 for each slot above the level 1st.