Dendrobium 'Woo Leng' Rescue: Keiki on Dead Cane, Repotting, and Dormancy Care

Question:

I inherited a Dendrobium 'Woon Leng' (tag says Woon Leng) from my aunt. Blooming when I got it in December; flowers died in February, I cut stalks close to canes. One cane lost all leaves (yellowed, fell off)—I overwatered initially until learning to use a bamboo skewer. That cane is brown/yellow from base up ~2 inches, hollow and dried. But above that, it's green and firm with a healthy horizontal shoot and stumpy green roots. Is this a "clone"? What to do? Second cane has a few green leaves, a 5-inch new shoot at base, and another small shoot emerging. What now—water? Fertilize? Repot? What about old canes that bloomed? Ever cut canes? First orchid—want to keep it alive for my aunt's memory!

Answer:

Susan, your hybrid is "Woo Leng" (tags sometimes fade). Time to repot—new growth has started. The dry, hollow cane section is dead. The healthy portion is producing a keiki (clone) to reproduce. During repotting, remove entire cane, separate healthy portion from dead. Repot healthy portion carefully—don't damage new roots. It's self-sustaining (derives no nutrition from dead part). Seal cut end with Rootone or powdered sulfur to prevent infection. You may remove the keiki and pot separately. Set remaining healthy cane aside in humidity—it may produce more keikis. Keiki can go in same pot or separate.

Dendrobiums normally lose leaves during dormancy—greatly reduce watering then. Failure to reduce causes rot and weak growth. Get orchid potting mix, soak portion overnight. Use slightly larger clay pot. Remove old mix and dead canes. Place plant, gently add fresh mix—don't damage new roots. Pack firmly; Dendrobiums like tight potting. Tamp down, add more until anchored. Bamboo stakes can support individual canes.

Follow-up: Questions on keiki handling: (1) Pull keiki off, or cut cane above/below and plant segment? (2) Seal cut end of healthy cane—does it go into mix? No roots visible except keiki's. (3) Came in square glass pot with wood chunks, no soil. Best clay pot—sealed or unsealed? (4) Approximate time to flower again? (5) Best orchid care book?

Follow-up Answer:

Any of three options works: (1) remove keiki and pot; (2) cut cane above/below keiki, seal ends, pot; (3) cut cane below keiki, seal, pot entire healthy cane with keiki. Nestle roots in mix so they don't dry out. Healthy cane may produce more keikis. Secure keiki/cane to bamboo stake.

Orchids need pots with lots of drainage holes. Dendrobiums prefer small unsealed clay pots—they breathe better but dry faster (water every couple days with fresh mix). Orchid mix is coarser than soil: fir bark, perlite, tree fern, lava rock, charcoal, sphagnum. Soak dry mix first (fir bark repels water).

Best book: Rebecca Northern's Home Orchid Growing. Local garden centers have selections. AOS website has info on common orchids.