Do I need a hub to control this with my phone?

The Smart Bridge allows you to control your Caséta Wireless controls and Lutron Serena® remote controlled shades from anywhere with your smartphone, using the free Lutron App for Caséta Wireless. The bridge provides multiple benefits over Wi-Fi products: It is ultra-fast and reliable ensuring your lights react instantly every time you adjust them from the app or Pico remote control. The bridge prevents the cluttering of your Wi-Fi network by acting as the single point of connection to the cloud. It is also easier to set-up and enables more local control/integrations with other smart home products. For more information about the Lutron bridge, please visit: http://www.lutron.com/TechnicalDocumentLibrary/3685682_why_a_bridge.pdf