Elderberries

Bees and butterflies help berry bushes grow faster.

Unlocks once you've harvested 130 Salmonberries, 100 Barberries and 80 Huckleberries in all; unlocking it is then free.

Grows on a berry bush, placed like a decoration for 750 spare parts and 75 biofuel, which fruits forever: a berry every 30m. It needs no water, fertilizer doesn't speed it up, and it earns no spare parts. Bees from a Beehive and butterflies from a Butterflies House bring it closer to ripe with every visit.

Rusty never picks berries: Berry Bots do, and so do visitors from Twitch chat when it's connected. In a Biofuel Converter each one is worth 54 biofuel. Feeder Bots never take berries to the animals, and the Reaper never offers chips for them.