Solar Sisters

Solar Sisters are bounty plants in Plants vs. Zombies: Battle for Neighborville. They can be hunted in Weirding Woods and come in a group of three. Defeating them unlocks the Sun Burned medal.

Strategies
Solar Sisters are unique in that they will respawn eight seconds after one of them is defeated, hinted by the "a sister regrows" message when it happens. This makes it an extremely difficult bounty hunt to attempt in single player. It is recommended to have at least three players perform this bounty hunt as each players can try to defeat all three of them at the same time.

The easiest way to defeat them is to use the Super Brainz, as he is suited for close quarters combat, not to mention that the Sunflowers have a rather weak firepower. Have each players attack all of them simultaneously. Once one of them is defeated, the other players will only have eight seconds to defeat the rest of the Sunflowers before she respawns. Use the Super Ultra Ball ability to finish them off quickly.

Attempting this bounty hunt in single player is possible, but is very difficult. You need to defeat them all within a very small time frame. A good way to defeat them is to use the Space Station, then lure them all so that they get closer together. After that, use the Crater Maker and beam them up quickly until all of them die. If the timer for the Crater Maker runs out, quickly dispatch the rest of the Sunflowers with the laser before the others respawn.

Coin, taco, and XP farming
This particular bounty hunt can be exploited to quickly farm coins, tacos, and XP, as well as being the fastest to perform. However, it requires at least three players due to the aforementioned difficulty in defeating them with less than three players. Simply use the Super Brainz with Fearless and Leveling Up upgrades, and defeat them multiple times until you get the desired amount of them. Beating this bounty hunt gives you at least 5,000 coins, 10 tacos, and 725 XP (796 XP with Leveling Up), and defeating the Solar Sisters takes around 15-30 seconds with one player; the quickest to perform compared to Bitey Brothers or Queenigma.