We actually eat water morning glory. My late uncle even went into canals to pick them, after which he bound them into heaps and sold them from house to house. We've also just started planting them in our backyard. We know them as water spinach or kang kong. We enjoy this vegetable with a lot of chilis and cook them with shrimp paste.
I didn't know you could cook water lilly's though... Please do make a post about it whenever you cook something with it π.