Yes.
They used a plant known as bear grass.
Grass and Sun!
grass+sunlight
Yes they do. But they are actually called inflorescences, since they do not flower like plants like Echinacea, Geraniums, or Apple trees do.
The grass flower generally have leafy bracts (lemma & palea), hence form a simple flower.
Grass and sunlight, and then you will have your flower.
grass+sunlight
Sun + grass = flower
Grass + Sunlight = Flower
Grass and sunlight, and then you will have your flower.
grass grows faster.
You can not really put anything in your flower beds to prevent grass, but if you happen to get grass in your flower beds, there is a product called Ortho Grass B Gon Garden Grass Killer. It kills grasses without causing any harm to flowers or groundcover.