Those plantlets on the leaf edges
Every notch along the leaf edge grows a tiny plantlet, complete with its own leaves and often a root or two. They drop off at the slightest touch and root wherever they land. That’s how the plant spreads, and it doesn’t need flowers or seed to do it.
Mother of thousands or mother of millions?
The common names get mixed up constantly, even between reference sources. “Devil’s backbone”, for instance, is used for both plants below. Go by the leaves instead:
- Mother of thousands (Kalanchoe daigremontiana). Broad, lance-shaped leaves up to about 8 in (20 cm) long, green on top and blotched with purple underneath. There are two small lobes where the leaf meets its stalk, and plantlets all along both edges.
- Mother of millions (Kalanchoe delagoensis, also sold as K. tubiflora). Narrow, almost tubular gray-green leaves with reddish-brown spots, and plantlets only at the leaf tips.
- The hybrid (Kalanchoe × houghtonii). A cross between the two, with narrower leaves than mother of thousands and little or no lobe at the base. It’s common in cultivation and is often sold under either name.
Care is the same for all three. The difference matters more if you live somewhere frost-free (see below).
Is mother of thousands invasive?
It can be, in warm places. Mother of thousands has gone wild in many frost-free regions, including Florida, Texas and Alabama. In Florida it usually turns up at the edges of natural areas, from discarded garden plants, and it forms dense thickets that are hard to clear because dropped leaves and plantlets keep starting new plants. The University of Florida’s assessment of non-native plants doesn’t currently rate K. daigremontiana itself as a problem species there. Its hybrid with mother of millions, K. × houghtonii, is listed as a Category II invasive by the Florida Invasive Species Council, and it carpets coastal dunes.
It can’t survive frost, so where winters are cold a potted plant poses little risk. Wherever winters are frost-free, keep it in a pot. Bag up trimmings and spare plantlets and put them out with the household trash, not in yard waste or compost.
Light
Bright, indirect light or a spot with a little gentle sun suits it. It tolerates some direct sun, but hot midday and long afternoon sun can scorch the leaves. Outdoors, partial shade is ideal.
Water
Water sparingly. Soak the soil, then let it dry out before you water again, and give it even less while it's resting and not putting out new growth. It shrugs off drought; overwatering, which rots the roots, is what kills it.
Soil & pots
Use a cactus potting mix in a pot with a drainage hole. Outdoors it wants sandy or loamy soil that drains well. Keeping it in a pot also makes stray plantlets much easier to control.
Temperature
It's happiest at 65–75°F (18–24°C) and isn't frost-tolerant. It can live outdoors year-round only in zones 9–11. Elsewhere, bring it in before the first frost.
Is mother of thousands safe for pets?
Toxic to cats and dogs. The ASPCA lists kalanchoe (Kalanchoe spp.) as toxic to dogs and cats, and its separate entry for mother of millions (K. tubiflora) says the same. NC State Extension adds that the sap can irritate skin, so wear gloves when you're clearing out plantlets.
Propagation
There's not much to it. The plantlets along the leaf edges are ready-made plants, often with tiny roots already. Spring is the best time to pot them up.
- Brush a few plantlets off a leaf edge onto a sheet of paper.
- Scatter them on top of barely damp cactus mix. There's no need to bury them.
- Keep them in bright, indirect light and water lightly when the surface dries.
- Pot up the strongest ones once they have a few pairs of leaves, and bin the rest.
Common problems
FAQ
Is mother of thousands toxic to cats and dogs?
Yes. The ASPCA lists kalanchoes as toxic to cats and dogs, with vomiting, diarrhea and, rarely, an abnormal heart rhythm. NC State Extension warns that a pet eating it can be an emergency, so call your vet straight away.
What's the difference between mother of thousands and mother of millions?
Mother of thousands has broad, lance-shaped leaves with plantlets all along the edges. Mother of millions (Kalanchoe delagoensis) has narrow, almost tubular leaves with plantlets only at the tips. See the comparison above.
Does mother of thousands flower?
Yes. The top of the stem produces an umbrella-shaped cluster of small, pink, bell-shaped flowers.
How do I stop it spreading?
Keep it in a pot on a tray, pick off plantlets before they fall, and put unwanted ones in a sealed bag in the trash. Don't toss them onto the garden or into yard waste or compost.
Can mother of thousands grow outside?
Year-round only in frost-free gardens in zones 9–11. Elsewhere it can summer outdoors in a pot, but it has to come in before frost.
Sources
- Kalanchoe daigremontiana Raym.-Hamet & H.Perrier: Plants of the World Online, Royal Botanic Gardens, Kew
- Kalanchoe delagoensis Eckl. & Zeyh.: Plants of the World Online, Royal Botanic Gardens, Kew
- Kalanchoe × houghtonii D.B.Ward: Plants of the World Online, Royal Botanic Gardens, Kew
- Kalanchoe: ASPCA Toxic and Non-Toxic Plants
- Mother of Millions: ASPCA Toxic and Non-Toxic Plants
- Kalanchoe daigremontiana: North Carolina Extension Gardener Plant Toolbox
- Kalanchoe delagoensis: North Carolina Extension Gardener Plant Toolbox
- Shaw, J.M.H. (2008). An investigation of the cultivated Kalanchoe daigremontiana group, with a checklist of Kalanchoe cultivars. Hanburyana 3: 17–79, Royal Horticultural Society
- Bryophyllum daigremontianum (devil's backbone): Florida Natural Areas Inventory
- Kalanchoe daigremontiana: UF/IFAS Assessment of Non-Native Plants in Florida's Natural Areas
- Kalanchoe species: UF/IFAS Center for Aquatic and Invasive Plants
- Invasive species, Mother of millions (Kalanchoe): UF/IFAS Extension Flagler County