Upgradeable plants

All the plants that can be upgraded into other plants.

• Repeater upgrades to Gatling Pea
• Sunflower upgrades to Twin Sunflower
• Fume-shroom upgrades to Gloom-shroom
• Lily Pad upgrades to Cattail
• Melon-pult upgrades to Winter Melon
• Magnet-shroom upgrades to Gold Magnet
• Spikeweed upgrades to Spikerock
• Kernel-pult upgrades to Cob Cannon

In Beghouled and Beghouled Twist, the game allows players to upgrade all of one plant type for the duration of the level:

• Peashooter upgrades to Repeater
• Puff-shroom upgrades to Fume-shroom
• Wall-nut upgrades to Tall-nut

In Air Raid, there is one upgradable plant:

• Gatling Pea upgrades to Threepeater

In Plants vs. Zombies 2, curtain plants can be planted on top of themselves to increase damage output:

• Pea Pod can be upgraded to have up to five heads, with each head shooting one pea each.
• Ultomato can be upgraded up to two times, dealing more damage at each stage, but causes each subsequent planting to cost more sun each time as a result.

In Plants vs. Zombies Online, Oxygen Algae can be upgraded permanently by Plant Food to encompass a larger planting area.