The Tenth China Flower Expo is out on Chongming island. It's a massive horticultural show. It runs until July 2. There are 180 outdoor gardens, and 64 indoor exhibitions. They’ve locked down nearly 10sqkm for it, and planted 470,000sqm of seeds. If you're into flowers, this is where you need to be in the next month. However, the journey out means it's probably not worth visiting it if you're anything less than an enthusiast. To get there you'll navigate their miniprogram (huabojiaotong on WeChat), and then the several modes of transport. Alternatively you can get a cab for about 450-500rmb each way. Entrance is 120rmb and you'll need to bring ID.