It is based on the plant in real life with the same name (Toxicodendron diversilobum), and an oak, a tree in the genus Quercus. However, Poison Oak being an oak tree is a visual pun on the word "oak" in "poison oak," as the poison oak, in real life, is a woody vine instead of an actual tree.
Poison Oak does not have the best stats for a 6-sun plant, but still can tank a few hits while fighting back with decent strength. But keep in mind that it is meant to attack your opponent and can be overwhelmed by zombies of the same cost, such as Template:PvZHLink, Wizard Gargantuar, and Template:PvZHLink. Therefore, you should consider carefully when and where to play Poison Oak.
The safest situation to play it is when your opponent uses all their brains to play zombies, allowing you to play Poison Oak safely on an unoccupied lane, although you are better off blocking attacks with it if the combined zombies' damage is greater than Poison Oak's damage, unless its attack will win you the game.
Each Kabloom hero has their own strategies with Poison Oak:
Solar Flare can make more sun, allowing her to play Poison Oak earlier and make it harder for your opponent to counter it.
Nightcap can Freeze or Bounce zombies in its way, protect it with Team-Up plants like Shellery and Navy Bean (although Spudow is better if you want to use that method), or play it on Template:PvZHLink to surprise opponents with poor aquatic defenses.
Spudow is a slight mix of Nightcap and Captain Combustible, as he has both Team-Up plants like Template:PvZHLink or Prickly Pear, as well as moving cards like Gardening Gloves or Bubble Up (to move Poison Oak itself, in this case). He can also use Spikeweed Sector to destroy weak zombies that are blocking it.
Against
Destroy it as quickly as you can before it ends up doing 9 damage to you. You can block Poison Oak with zombies until it is destroyed. However, the easiest and fastest way to destroy it is to use instant-kill cards such as Cut Down to Size, Locust Swarm, and Rocket Science. Using Fire Rooster along with Zombot Sharktonic Sub against it can also finish it off very quickly. Deadly zombies can also destroy it in a single hit. If you predict that your opponent might play this, do not spend all your brains on zombies, as otherwise, you will be left with nothing to block it.
Gallery
Poison Oak's statistics
Poison Oak's card
Poison Oak's grayed out card
Poison Oak's card image
HD Poison Oak
The player earning Poison Oak after completing the 8th step in Spudow's Hero Quest