The Meilong Bird and Flower Market is in Minhang, on 66 YiMei Rd, near Shangzhong Rd and Lianhua Rd (the GPS all tell you to get to it via Hongmei South Rd, but, that’s incorrect. Go via Lianhua Rd.)
It’s a great place for plants and flowers of all types. The sellers are pretty honest with pricing.
Huge tree-like plants, 2m tall, are around ¥120-200. Standard house pot-plants are around ¥50-100 and little succulents are around ¥5-10.
Obviously no one there speaks English and you need Chinese.
As well as plants, they sell aquariums and fish, budgies, chipmunks, rabbits, cats and dogs (while this is generally not a wise place to get cats and dogs from), terrapins, crickets and insects, and a few other things.
So as well as home decor, you can take the kids there for a 30-minute trip.
If you want to know specific kids stuff nearby, then Wells Jumping is about 20 minutes away, and the Shanghai Botanical Gardens (NOT Chenshan Botanical Gardens, which is better and about 30 minutes away) is 15 minutes away.