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.
Generation VII
A Chilan Berry will mature from a planted seed to a full-grown, fruit-bearing tree in 48 hours. A Chilan tree will yield 2-6 Berries.
Poffin cooking
At 100% performance, this Berry can produce a Level 20 (maybe higher) Dry-sweet Poffin.
Unlike the other damage-reducing Berries, the Chilan Berry weakens attack damage (except by moves that deal direct damage) regardless of type effectiveness, instead of super effective damage only. This may be because Normal-type moves cannot normally be super effective.
The Chilan Berry does not weaken Present if it heals the target.
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.