Tengu format ruling
Rose Tentacles

Card effect (current official text)Cannot be Special Summoned. At the start of your Battle Phase, for each Plant-Type monster your opponent currently controls, this card gains 1 additional attack during each Battle Phase this turn. Each time this card destroys a Plant-Type monster by battle: Inflict 300 damage to your opponent.
Rulings
- The restriction against Special Summoning "Rose Tentacles" is not an ‘effect’.
- The effect of "Rose Tentacles" to inflict damage happens at the end of the Damage Step.
- You can combine the effect of "Rose Tentacles" with "Wonder Clover:"
- If your opponent controls 0 Plants, "Rose Tentacles" could attack twice. If your opponent controls 1 Plant, "Rose Tentacles" could attack twice.
- If your opponent controls 2 Plants, "Rose Tentacles" could attack 3 times
- The number of attacks that "Rose Tentacles" can perform is determined at the start of the Battle Phase.
- If the number of Plants changes, the number of attacks "Rose Tentacles" can perform doesn’t change.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.