To get Twin Sunflower, the player must buy their seed packet from Crazy Dave’s Twiddydinkies for $5000. They appear on sale after beating Level 3-4, along with the Gatling Pea. They cost 150 sun to plant and must be placed on an existing Sunflower. Twin Sunflower doubles the sun production of the Sunflower, which means they increase from 25 sun every 24 seconds to 50 sun over the same amount of time.
Twin Sunflowers can be used for later and longer levels that require heavier offensive plants or abilities. They are especially valuable in Survival Mode due to lack of space for many Sunflowers. Although Twin Sunflowers are not as efficient as Sunflowers, they take up half the space as Sunflowers producing the same amount of sun, so are more helpful for levels with large numbers of zombies that require more space for offensive plants.
Use Umbrella Leaves to protect Twin Sunflowers, especially those in the back of the lawn, against the Bungee Zombies and Catapult Zombies. Though it’s possible to defeat Bungee Zombies before they steal the Twin Sunflowers, it’s generally safer to use Umbrella Leaves, as they also block Catapult Zombies from damaging them too.
Digger Zombies can also be a problem, so protect Twin Sunflowers with Pumpkins or place them in the second column to place a defensive plant on the first.
Flower Power achievement
If you plant ten Twin Sunflowers and keep them alive, you will earn the Flower Power achievement. The easiest way is to get the achievement is to play an easy level. Play any Survival level (excluding Endless), preferably Survival: Pool, (due to it being a level in the daytime that has six rows) and plant Sunflowers to be upgraded to Twin Sunflowers. It is recommended that you protect them with Pumpkins and Umbrella Leaves. Replace the Pumpkins if needed. Of course, use your usual Survival strategy for that level. All ten Twin Sunflowers should make it through to the end.
Alternatively, the player can play ZomBotany 2, because there are three flags. A good strategy for that is to have two Garlics up front adjacent to the pool lanes, followed by three Gloom-shrooms behind the Garlics, and then the filling the rest of the empty space behind the Gloom-shrooms with Twin Sunflowers. This ensures that the Twin Sunflowers will be safe from Peashooting Zombies, though one should be careful of squash zombie destroying the Garlics.