Purée 4 chopped celery stalks and 1/4 cup water in a blender. Strain into a pitcher filled with ice, pressing on solids; discard solids.
Add 1/3 cup fresh lemon juice, 1/3 cup Simple Syrup, and 1/4 teaspoon Bittermens Hellfire Habanero Shrub or Angostura bitters*; stir until cold. Divide among 4 Collins glasses filled with ice and add 2-3 ounces club soda to each.
Garnish with celery stalks.
*Most bitters contain alcohol. For a 100% nonalcoholic drink, use Fee Brothers' celery bitters.