It became available on the Zombie's LuckWeekly Event and was available from March 22th, 2017, to March 28th, 2017, and was also available in an Early Access Pack from March 7th, 2017, through March 14th, 2017.
It is based on a shamrock, a young spring of a clover used as the symbol of Ireland, and a rocket, a missile, spacecraft, aircraft, or other vehicle that obtains thrust from a rocket engine.
Its name is a portmanteau of "shamrock," the real-life plant it is based on, and "rocket," the real-life object it is based on.
Its description is a reference to the idiom "the bigger they are, the harder they fall."
Statistics
Class: Guardian
Tribes: Leafy Pinecone Trick
Ability: Destroy a Zombie that has 4 or more.
Set: Event
Card description
The bigger they are, the harder they go boom.
Update history
Update 1.12.6
Added to the game.
Update 1.14.13
Tribe added: Pinecone
Update 1.16.10
Became craftable.
Strategies
With
Shamrocket is basically the plant counterpart of Rocket Science, due to them having the exact same use. However, unlike Rocket Science, Shamrocket can't be used on zombies that were boosted through tricks on that turn, meaning you have to take the hit and retaliate next turn. On the other hand, since plants play after zombies, you can destroy a high-strength zombie before your opponent can boost it or make it do a bonus attack. Generally, you can also aim to destroy powerful zombies with Shamrocket like Zombot 1000, Nurse Gargantuar, Wizard Gargantuar, and other zombies that have more than 4 strength. However, since you can only have four in a deck, only use them on zombies that will cause you a lot of trouble.
Shamrocket also serves as an alternative to Template:PvZHLink as you can destroy a single zombie that has high strength, while at the same time keeping your high-strength plants intact. However, if you expect that the zombie hero will play multiple high-strength zombies, then Doom-Shroom should be used as it affects multiple fighters.
Against
Be careful when facing a Guardian hero, as boosting your zombies may cause them to be destroyed by this trick. The hero that you should be most cautious of is Wall-Knight, since he can pair it up with Template:PvZHLink, which will allow him to destroy all zombies regardless of strength for 3 sun. It is difficult to anticipate if your opponent has this card, and therefore, it can be hard to counter. The best way to prevent this trick from wrecking you is to play lots of Gravestone zombies, as they cannot be affected by it until the turn after they are played, but then you have to watch out for Template:PvZHLink and Blockbuster.
You can also play lots of zombies with 3 strength or less, though later in the game, this strategy becomes less reliable. If you want to play a zombie with at least 4 strength but want to prevent it from being destroyed by this trick, you can use Teleport or Teleportation Zombie to play it in the Zombie Tricks phase, protect them with Template:PvZHLink, or delay it with Defensive End.
Shamrocket on an advertisement for the Event Rewind Bundle
Old
Shamrocket's statistics before update 1.14.13
Trivia
In the Russian version and other localized versions of Plants vs. Zombies Heroes, this card has a mistake in the statistics, stating that this trick destroys a plant with 4 or more.