Sempervivum 'Red Beauty': The Crimson Houseleek

Sempervivum 'Red Beauty' is a red-pigmented cultivar widely traded across Europe and North America for its intense crimson rosette colouring, most striking in autumn. The exact parentage is not formally recorded; the plant sits in the S. tectorum × S. marmoreum hybrid group alongside many other red-expressing selections.

Part of the Complete Sempervivum Guide.

Do not confuse it with S. tectorum 'Red Beauty' (a distinct older selection), S. calcareum 'Sir William Lawrence' (which has a similar colour but a red tip rather than a whole red rosette), or any of the "Red" cultivars in the Chick Charms series. In practice, mass-market labelling is inconsistent and any red-rosetted flat sempervivum in a garden centre may be labelled 'Red Beauty'. Buy from a named-cultivar specialist if provenance matters.

Identification

• Rosettes. 5–9 cm across at maturity, flat and open, in the tectorum mould.
• Leaves. Obovate, 2–4 cm long, glabrous with short ciliate margin hairs. The colour is the diagnostic character: in full sun and cold, the entire leaf turns a deep uniform crimson-red, sometimes with a darker wine-red tip. In summer heat the centre shifts back toward olive-green while the outer leaves retain red, giving a two-toned "red outer, green heart" appearance.
• Seasonal expression. Pigment peaks in late autumn (October–November in the northern hemisphere) after the first real frosts. A cold snap of −2 °C to −5 °C dry cold triggers the maximum anthocyanin accumulation. Summer specimens in hot climates can look disappointingly muted; do not judge the cultivar on July photographs.
• Inflorescence. Standard tectorum-group pink star-shaped 12-petalled flowers on a 25–35 cm scape.

Cultivation

The fundamental rule for all red-expressing sempervivums applies in full here: anthocyanin is a cold and UV stress response, not a stable structural pigment. To keep 'Red Beauty' red you need the stress. Specifically:

• Full unfiltered sun, six hours minimum.
• Cool nights. The colour shift begins when night temperatures drop below 12 °C.
• Lean substrate. Avoid nitrogen fertiliser entirely; even a dilute feed will green the plant within two weeks.
• Drought stress. Let the substrate dry completely between waterings. Water once, then leave alone.

Plants in partial shade or regularly watered stay olive-green. This is reversible: move a green plant back into lean conditions and the colour returns within a season.

Hardiness is USDA zones 4–8, −30 °C reliable when dry. This is genus-typical; the cultivar offers no special hardiness benefit.

Propagation

Offset division. Chicks come true to parent clone and are red from emergence. Standard technique: cut stolon, lift chick, replant in gritty substrate, water lightly once. Establishment in 2–3 weeks.

Do not propagate from seed; seed-grown offspring will segregate and most will revert toward less vivid coloration.

Notes and Quirks

A common customer complaint about 'Red Beauty' is that "it went green". In virtually all cases the plant is fine and the cultivation is too kind. Move it to a sunnier lean-soil position and wait for the first cold nights.

For maximum ornamental effect, interplant with contrasting colour cultivars. 'Red Beauty' next to a blue-glaucous selection like 'Pacific Blue Ice' or a gold-leaved cultivar like 'Gold Nugget' makes a much stronger trough display than 'Red Beauty' alone.

See also

• Sempervivum 'Ruby Heart' — related red cultivar with concentrated red centre.
• Sempervivum 'Pacific Blue Ice' — the blue contrast companion.
• Sempervivum 'Black' — the darker end of the same pigmentation spectrum.
• Sempervivum 'Gold Nugget' — the gold complement in a mixed trough display.