How do druids keep other druids from using Transport via Plants to show up uninvited?

What options do druids have to keep other druids out of their sacred groves?

Some contrasting examples:

  • Wizards like to Teleport. To keep out other wizards, a wizard can use Dimensional Lock (on an admittedly tiny area).
  • Clerics don’t have a lot of teleportation spells. To keep out those clerics with access to the Travel domain, other clerics could cast Dimensional Lock or Forbiddance.

Druids probably have a tree or eighty nearby. If a druid wants to go somewhere using Transport via Plants, I imagine having any "normal plant (equal to the druid’s size or larger)" around would be both convenient and thematic.

The options I have found so far to prevent uninvited druids from showing up via either Transport via Plants or Tree Stride:

  1. The druids kill all the vegetation nearby. This seems kinda…. anti-druidic.
  2. Create a House Rule that druids can cast Forbiddance on one grove, and one druid may have only one Forbiddance spell in effect at one time. I’m probably going to do this, but not sure what else it will break.