When Can You Lead With Hearts?

Short Answer
You can lead with a heart card only after hearts have been "broken." Hearts are broken when any player plays a heart on a previous trick (usually because they had no cards in the led suit). Once broken, hearts can be led for the rest of the hand.

How Hearts Get Broken

Hearts break when:

Example

Player 1 leads the 7 of Clubs. Player 3 has no clubs, so they play the 5 of Hearts. Hearts are now broken. On Player 3's next lead, they can start with any heart.

The Exception: Only Hearts Left

If a player's remaining cards are all hearts and hearts haven't been broken yet, they may lead a heart. This exception prevents impossible situations where a player literally cannot make a legal play.

Strategy Around Breaking Hearts