The Yellow Cannon is available to you once you have 12 bee types. It is located on a hill accessible from the Pineapple Patch, next to Science Bear. If you use it without any power-ups or other tools (e.g. parachute), you'll land in the spawn area or near the Dandelion Field near the hives.
The Yellow Cannon combined with the Parachute can be used to get the Royal Jelly from the top of the tallest dandelion, as well as the one in front of the Star Hall. With luck and perseverance, it is also possible to reach the top of the hives with the yellow cannon+parachute, which will enable you to get the Royal Jelly behind the Onett NPC. That last one is much easier with the Glider, though.