You touch a wooden object of Medium Size or a section of plant matter 5 feet in any dimension and rapidly accelerate its growth. Sturdy tendrils of the material shoot from the point up to 30 feet away (including up), creating a solid barrier five feet across in any direction. Upon casting this spell, you decide whether or not this plant matter counts as difficult terrain for the purposes of climbing or crossing. In addition, each time the plant matter moves, you may attempt to grapple a creature within five feet of the plant matter, using your spell attack modifier for the check instead of a Strength (Athletics) check, and may move grappled creatures with the plant's movement if they are Medium creatures or smaller.
On subsequent turns while concentrating, you may spend an action either to extend the tendril an additional 30 feet and reattempt a grapple, or refine its shape. The tendrils can only be extended up to 120 feet from the point of origin, but can carry grappled creatures for the duration. The tendrils cannot break through sturdy objects, and will harmlessly fill enclosed spaces. If chosen to refine the shape, simple shapes can be formed with and on the surface of the plant matter, but finer mechanical detail isn’t possible.
Upon ending concentration, the plant matter will wither away, harmlessly depositing any creatures grappled by it onto the ground. If the full duration of the spell is reached, you may choose to have the plant matter remain in the space it has filled.