Kalanchoe × houghtonii
alligator plant
Garden origin; parent species from Madagascar
Overview
Kalanchoe x houghtonii is an erect succulent reaching 1–3 feet (30–90 cm) tall, a hybrid between Kalanchoe daigremontiana and Kalanchoe delagoensis. It grows on a single fleshy stem bearing narrow, lance-shaped to channeled gray-green leaves 2–6 inches (5–15 cm) long, often mottled with purple beneath. Plantlets, each a tiny rooted clone, form in rows along the leaf margins and drop to root where they land, so a single plant generates colonies quickly. Clusters of tubular flowers 0.5–1 inch (1.3–2.5 cm) long, pink to orange, hang from tall stalks in winter. The plant tolerates heat, drought, and poor soil but is killed by frost below about 30°F (−1°C). All parts contain bufadienolide cardiac glycosides that are toxic to people, pets, and livestock if eaten. It has naturalized and become invasive in warm regions of Australia, southern Africa, and the southern United States, where shed plantlets form dense stands. Growth is fast in containers, and the plant escapes garden beds through dropped plantlets.
Native Range
Kalanchoe x houghtonii is a hybrid of garden origin, derived from two species native to Madagascar. It has no natural wild range but has naturalized in subtropical and arid regions worldwide. In several countries it is listed as an invasive weed.Suggested Uses
Grown as a container succulent and houseplant for its plantlet-bearing foliage and winter flowers. In frost-free climates it is used in dry rockeries and succulent beds, though its spread limits such plantings. It is kept in pots where dropped plantlets can be contained.How to Identify
Appearance
Size & Dimensions
Height1' - 3'
Width/Spread6" - 1'
Reaches mature size in approximately 2 years
Colors
Bloom Information
Flowering occurs in winter, from about December to February, when clusters of pendent tubular flowers open pink to orange on stalks held above the foliage. Bloom follows a period of short days and cool nights. Plants often die back after heavy flowering, leaving behind the rooted plantlets. Flowering is sparse on plants kept in deep shade.
Detailed Descriptions
Flower Description
pink to orangeFoliage Description
gray-greenGrowing Conditions
Sun Requirements
Requires 5-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Bright light to full sun and fast-draining, gritty soil suit Kalanchoe x houghtonii. The plant stores water in its leaves and needs only occasional deep watering, with soil allowed to dry between waterings. Soggy soil causes stem and root rot. It is hardy only in USDA zones 9–11 and grown as a container plant elsewhere, moved indoors before frost. Indoors it grows in a bright window with monthly water in winter. Dropped plantlets root in surrounding pots and beds, so spent leaves and bulbils are gathered to limit spread.Pruning
Removing flower stalks after bloom and cutting back leggy stems keeps plants compact and prompts branching. Picking off the marginal plantlets before they drop reduces unwanted spread. Cut stems and leaves root readily if left on the soil surface.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter
Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons