October Daphne (Hylotelephium sieboldii), also commonly known as Stonecrop 'October Daphne' or Siebold's Stonecrop, is a charming deciduous succulent perennial belonging to the family Crassulaceae. This low-growing, mat-forming plant is prized in horticulture for its distinctive rounded blue-green foliage, delicate pink autumn blooms, and exceptional cold-hardiness among succulents.
• Native to Japan, where it has been cultivated as an ornamental plant for centuries
• One of the few succulents that thrives in cool to cold temperate climates, tolerating frost and even light snow
• The common name 'October Daphne' refers to its late-season flowering period in autumn
• Formerly classified under the genus Sedum as Sedum sieboldii before taxonomic reclassification into Hylotelephium
• Widely used in rock gardens, ground covers, green roofs, and container plantings
Taxonomie
• The species is named after the German physician and botanist Philipp Franz von Siebold (1796–1866), who made extensive collections of Japanese flora during his time in Japan in the 1820s–1830s
• Siebold introduced numerous Japanese plant species to European horticulture, and many bear his name
• The genus Hylotelephium was segregated from the broadly defined genus Sedum based on molecular phylogenetic studies in the late 20th and early 21st centuries
• The Crassulaceae family (stonecrop family) comprises approximately 1,400 species across 35 genera, distributed primarily in the Northern Hemisphere and southern Africa
• Hylotelephium species are predominantly found in temperate regions of East Asia, Europe, and North America
Stems:
• Slender, arching to semi-prostrate, often rooting at nodes where they contact soil
• Green to reddish-green, smooth, and somewhat brittle
• Grow from a fibrous rootstock; the plant dies back to the ground in winter and re-emerges in spring
Leaves:
• Arranged in characteristic whorls of three along the stem (a key identifying feature)
• Nearly round (orbicular), ~1.5–3 cm in diameter
• Fleshy and succulent, storing water in thickened parenchyma tissue
• Distinctive glaucous blue-green to grey-green coloration with subtle reddish margins
• Margins may develop pink to red tints in cooler temperatures or under bright light
• Deciduous — leaves drop after frost in autumn
Flowers:
• Produced in dense, flat-topped to slightly domed corymbs (clusters) at stem tips
• Blooming period: September to November (autumn)
• Individual flowers are star-shaped, ~8–12 mm across, with five petals
• Petals are pink to rose-purple, sometimes deepening to magenta
• Flowers are hermaphroditic and attract pollinators including bees, butterflies, and hoverflies
Fruit & Seeds:
• Develops as a follicle (a dry fruit that splits open along one side)
• Contains numerous minute seeds adapted for wind dispersal
• Naturally found on rocky outcrops, stone walls, and dry slopes in Japan
• Adapted to full sun to partial shade; performs best with at least 4–6 hours of direct sunlight
• Exhibits CAM (Crassulacean Acid Metabolism) photosynthesis — stomata open at night to minimize water loss, a key adaptation to arid or exposed conditions
• Cold-hardy to approximately -20°C to -25°C (USDA hardiness zones 4–9), making it one of the most cold-tolerant succulents in cultivation
• Autumn flowering provides a valuable late-season nectar source for pollinators when few other plants are in bloom
• The plant enters dormancy in winter, with above-ground parts dying back completely; the rootstock survives underground through freezing temperatures
Light:
• Full sun to partial shade
• At least 4–6 hours of direct sunlight daily for best foliage color and flowering
• In hot climates, light afternoon shade helps prevent leaf scorch
Soil:
• Extremely well-drained soil is essential; tolerates poor, sandy, or rocky soils
• Avoid heavy clay or waterlogged conditions, which cause root rot
• Ideal pH: slightly acidic to neutral (6.0–7.5)
• For containers, use a gritty succulent/cactus mix with added perlite or coarse sand
Watering:
• Drought-tolerant once established; water sparingly
• Allow soil to dry out between waterings
• Reduce watering significantly during winter dormancy
• Overwatering is the most common cause of failure
Temperature:
• Thrives in cool to cold temperate climates
• Hardy to approximately -20°C to -25°C
• Performs poorly in hot, humid tropical climates
Propagation:
• Easily propagated by stem cuttings taken in spring or early summer
• Division of established clumps in early spring
• Stem sections root readily when placed on moist, well-drained soil
• Seeds can be sown in autumn or spring but are slow to establish
Common Problems:
• Root rot from overwatering or poorly drained soil
• Mealybugs and aphids may occasionally infest new growth
• Leggy growth in insufficient light
• Foliage may lose its blue-green color and turn plain green in deep shade
Anecdote
October Daphne belongs to a group of plants that literally 'breathe' at night. Like many members of the Crassulaceae family, it uses CAM photosynthesis — a specialized carbon-fixation pathway in which the plant opens its stomata only at night to take in CO₂, storing it as malic acid for use in photosynthesis during the day. This remarkable adaptation, which evolved independently in multiple plant lineages, reduces water loss by up to 90% compared to typical C3 plants. The genus name Hylotelephium has a curious etymology: it derives from the Greek 'hylo-' (forest/wood) and 'telephion' (a name used by Pliny the Elder for a plant thought to be native to a distant island), essentially meaning 'forest plant from afar.' The taxonomic history of this group is complex — for over a century, these plants were buried within the enormous genus Sedum (which once contained over 600 species), before DNA evidence in the 1990s and 2000s revealed that Sedum, as traditionally defined, was not a natural (monophyletic) group. Philipp Franz von Siebold, for whom the species is named, was arrested and expelled from Japan in 1829 after being caught smuggling restricted maps and botanical specimens out of the country during Japan's period of national isolation (sakoku). Despite this dramatic episode, his botanical collections profoundly shaped European understanding of Japanese flora, and his legacy lives on in the names of dozens of plants — including this elegant autumn-blooming succulent.
En savoir plus
