Loire C
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Great! Many gardens for typical plant/ flowers, greenhouses for tropical and Succulent plants.
The cymbidium room is not a "room", it is big garden housing Chinese orchids, many of them are precious bonsais. The history of this cymbidium room (70 years) is longer than the whole botanical park (40+ years).
Free entry, needs pre-booking online, particular halls, greenhouses require entry fees but very cheap.