Two simple routes lead to the Garden in Grounded 2’s Toxic Tangle update
Polygon reports the Toxic Tangle update for Grounded 2 adds the Garden as the update's first challenge, located in a new sliver of the northeastern Grass Games region near the back door of the Flower Bed Ranger Station. There are two main ways in. The easier involves heading east toward the wall by a puddle before the ranger station (watch for stinkbugs; a gas mask can help), then entering the western entrance of the War-Torn Anthill.
Using a red ant buggy lets you pass through the red ant side—turn left at the first fork and ride through a large chamber with a giant blob—before emerging in the black ant half, which will attack even if you remain mounted. The tunnel opens onto the northwestern corner of the Garden; the immediate area is mostly free of dangers though tougher bugs are nearby and a cricket appears to the south at night.
The faster method skips the anthills but requires the orb weaver mount: climb the stick by a faucet against the wall, walk along the brick wall, hop across leaves to the spiderweb under the faucet, then climb the web while mounted to reach the hedge and drop into the Garden. You can also build stairs up the wall if you prefer a permanent shortcut.