I made a stop at the Dalat Flower Gardens which was an entertaining combination of kitch and first class nursery. Like LP says, before long they may be calling it a botanic garden.
There was a big flower festival here in 2005 and in general I think the attention to landscaping is very high. Once out of the city center, which is a messy-moto-noise-fest, you see many public gardens, flower beds, and well tended private yards.