A Chilan Berry will mature from a planted seed to a full-grown, fruit-bearing tree in 72 hours, with 18 hours per stage. A Chilan tree will yield 1-5 Berries.
Generation VI
A Chilan Berry will mature from a planted seed to a full-grown, fruit-bearing tree in 48 hours, with 8 hours per stage. A Chilan tree will yield 3-20 Berries. During its growth, watering the plant will add 1 Berry to the final harvest, weeding it will add 0.5, and removing a pest will add 2.
Poffin cooking
At 100% performance, this Berry can produce a Level 20 (maybe higher) Dry-sweet Poffin.
When buying Chilan Berries in Join Avenue, the text will say "A set of four Chilan Berries. They weaken a supereffective Normal-type attack against the holding Pokémon." This is most likely a mistake since all other damage-reducing Berries only work if the attack is super-effective.