Cutting Back a Tall Cactus in New York: Replant the Top, Wait for Spring

3-Foot Summer Growth Makes Cactus Too Big for Indoors

New York gardener's cactus (possibly Pilosocereus royenii) grew 3 ft, now too tall to bring inside. Asks if she can cut it back and what to do with the piece.

Yes—Cut, Callus, Replant

Greg says cut the top, let it callus at least 3 weeks, then plant in soil. Water only after soil dries completely. Rooting may take 4–5 months this time of year; spring is better. The remaining base may branch below the cut.

Winter Care for Base

• Keep cool (40–50°F), bright light.
• Water once a month or less.
• No fertilizer until spring.

The cutting is a backup; the mother plant may also resprout.