Crassula arborescens subsp. undulatifolia Max Cook

Full sun to part shade, by the NC State toolbox. LLIFLE says it does well in filtered sun and takes some shade, that the leaves stay greener in shade and can turn pinkish in harsh sun, that it can scorch if moved from shade into full sun too quickly, and that it gets leggy in deep shade.

LLIFLE asks for a sandy, gritty soil and says good drainage matters because it is prone to root rot; the NC State toolbox asks for a succulent mix in a clay pot with several drainage holes, watered only once the plant has dried out. LLIFLE calls it very dry tolerant and warns that cold, wet soil in winter can cost it its roots.

LLIFLE says to protect it from frost to prevent scarring, and gives it hardy to -5 C, at times -7 C, for short periods in dry soil; both references give USDA zones 9 to 11.

The NC State toolbox names mealybugs and scale insects; LLIFLE names mealybugs, and scale only rarely. The NC State toolbox roots stem cuttings dried for 24 to 48 hours; LLIFLE adds leaves and seed.

The NC State toolbox and LLIFLE disagree on its speed, slow by the first and moderately fast by the second.

LLIFLE gives it for pots, the house and bonsai as well as the open garden, where it suits a hot, dry rockery or a sunny patio; the NC State toolbox lists it for containers and rock gardens. The toolbox counts the rippled leaves attractive all year, though the plant rarely flowers in a container; LLIFLE says a plant in flower, in spring to summer, is almost completely covered. Where frost is likely, LLIFLE grows it in pots in an intermediate greenhouse or conservatory.

Check what the label covers. The name Max Cook appears on growers' lists but in no reference read, so whether it is one clone or a trade name for the subspecies cannot be settled here. LLIFLE treats the plant long sold as Blue Bird, or Crassula portulacea 'Blauwe Vogel', as the same as this subspecies, while HortFlora calls Blue Bird of uncertain identity, possibly this subspecies; Blue Bird has its own page. The straight species has thick, rounded leaves by LLIFLE, up to about 7.5 cm long and 2.5 to 7.5 cm wide by the NC State toolbox; ripple jade's are 8 to 15 mm broad, twisted and wavy-edged by LLIFLE. The table above shows the sizes growers list. What to look for in the roots and for pests before stock leaves the grower is in the guide to nursery plant quality.

The ASPCA lists Crassula arborescens, the species, as toxic to dogs and cats, with nausea and retching as the signs; the entry is for the species, and the NC State toolbox tags this subspecies a problem for cats.