by Bruce Brethauer
Crassula falcata, the "Propeller Plant" is one of the more unusual members of the Genus crassula - which includes such familiar plants as the Jade Plant, the Watch Chain Plant, "Buddha's Temple" and many others. It produces clusters of upright and semi-upright stems to 3 feet tall, but most of the plants which I have seen in cultivation are generally smaller, usually growing to about 12 to 24 inches. The curiously twisted and curved succulent leaves are indeed reminiscent of a propeller; even its varietal name, falcata, meaning "shaped like a sickle" alludes to its uniquely shaped leaves. Individual leaves measure to about 4 or 5 inches in length, and to about 1 inch across. The entire plant has a dullish grey-green coloration, giving the leaves and stems a frosted, or waxy appearance.
The crowning glory of the "Propellor Plant", alias the "Scarlet Paintbrush" are its magnificent flowers; large corymbs measuring to 6 inches or more across, containing hundreds, if not thousands of densely packed, star-shaped florets - each measuring from about 1/4 to 1/2 inch across. The flowers are of a bright carmine to crimson red, and contrast well with the bright yellow anthers. The brilliant colors of these flowers draw attention to the plant, and can make a very lasting impression: even today, I recall that I was particularly struck by this plant's floral display when I first encountered it during a visit to the Ruth Banchroft garden back in 1993. The flowers are long lasting, putting on their brilliant display for 2 to 3 weeks or more, although the flowers will trend to become increasingly faded with time. Following the initial display, additional flowers may be produced of a number of side shoots, increasing the total display by several weeks. I believe that I had heard that the individual stems of this plant are monocarpic, dying back after flowering, but this has not been the case with my plants. The inflorescense does appear to be terminal, so additional flowers will eventuially be produced from side branches.
The "Propeller Plant" is native to the Cape of Good Hope region of South Africa, and is closely related to Crassula perfoilata - and today, most authorities regard it as a subspecies of this plant. I have used both names here as I believe that its older name (Crassula falcata) will be more familiar to many growers.
This is an undemanding and easy plant, and should grow well given my basic guidelines for growing cacti and other succulents, but it does require bright light to produce characteristic growth, and to produce its best display of flowers. In frost free, or nearly frost free areas of California, Arizona, and Texas for example, it is frequently grown outdoors as a drought resistant garden perennial. Growers in other regions should move their plants outside during the warmer months of spring, summer and fall to benefit from full exposure to sunlight, warm temperatures, and rainfall, as plants grown exclusively in the relative darkness of home interiors may produce rather insipid looking, etiolated growth. For this same reason, winter growth should be kept to a minimum by keeping the plant dormant by maintaining cooler temperatures, and keeping the plant much drier throughout the winter months (watering only enough to prevent root loss, and to keep the leaves from shriveling). While I am not certain of this, a cool and dry winter dormancy may also be necessary for the later development of flower buds. While plants of this variety will tolerate a few degrees of frost, I do not know their ultimate tolerance to cold, so whenever plants are moved outdoors, they should be brought back inside whenever temperatures approach 40 degrees Fahrenheit or colder. While I grow my plants in the basement under lights during the winter months, I expect that this plant would be an excellent candidate for over-wintering in a Florida room or similar space, where the lighting in winter is good, and temperatures are cool, but do not fall below freezing.
It is easy to propagate additional plants by rooting the basal offsets: just cut off one of the offsets, allow the cut end to heal and callus for about a week or so before potting it up in a sharply draining medium. Keep the soil just barely moist until the cutting establishes new roots, and then treat it as you would an established plant. Oftentimes, the basal offsets will already have small roots when the cuttings are taken - these will become established even faster than the unrooted cuttings. I would recommend taking cuttings from spring through early summer when the plant is showing new growth. Once cutting grown plants are established, growth can be fairly rapid, so that a well grown plant may flower in the next year. It is also possible to grow this plant from leaf cuttings, and from seed, but I imagine that it would take at least an additional year for either of these to reach flowering size.
This is an attractive plant, which should be more commonly grown - not only is it an interesting houseplant, but if offers some interesting possibilities as a plant for a succulent patio planter. This plant is practically immune to drought, thrives in full sun and summer heat, and best of all, it tolerates benign neglect, all conditions which would whither many other container plants. Its curious leaves provides a curiously attractive sculptural framework, and its brilliant, long lasting flowers are the icing on the cake. While in some regions of the country, where it is sometimes grown as a garden perennial, I imagine that the Propeller Plant is a common feature in garden centers - in other regions, it is practically unknown. Fortunately, several members of the Central Ohio and Midwest Cactus and Succulent Societies grow this plant, so in our area, we have ready access to starter cuttings. Growers in other regions would also do well to check with area cactus societies first- but plants can be found online and through mail order nurseries specializing in succulents. For those persons who are ready to take a step beyond the ubiquitous Jade Plant, this would make an excellent choice.
Sources for this plant:
Bob Smoley's Gardenworld
Arid Lands Nursery