Wachendorfia thyrsiflora Burm.
Common names: marsh butterfly lily, bloodroot, redroot (Eng.); rooikanol (Afr.)
Wachendorfia thyrsiflora with its large golden flower spikes is very striking when in flower.
Wachendorfia thyrsiflora is a must for the marshy garden. It is a tall evergreen geophyte (perennial plant with underground buds). The rootstock is a branched, fleshy rhizome with clusters of thin adventitious roots at the nodes. The rhizome is a distinctive red colour, containing a red fluid rich in arylphenalenone pigments. The leaves are firm, hairless, entire and broadly sword-shaped, with very distinctive longitudinally pleated leaf blades. The inflorescence is a dense cylindrical panicle of bright golden-yellow flowers on a tall sturdy stalk. Flowers are produced from spring until mid-summer (September - December). The leaves are from 0.6 to 1 m tall, and the flower stalks can reach up to 2.5 m in height.
According to the Red List of South African Plants, this species has a stable wild population, is not facing any threats and is thus assessed as Least Concern (LC).
Distribution and habitat
Wachendorfia thyrsiflora occurs in the Western Cape and Eastern Cape, from the Olifants River Valley between Clanwilliam and Citrusdal, south to the Cape Peninsula, inland as far as the Franschhoek Mountains, and along the south coast as far east as Humansdorp, where it grows only in permanent marshes, seepages and streams from 5 to 1200 m above sea level.
Derivation of name and historical aspects
The Haemodoraceae or bloodwort family gets its rather alarming name from the red cell-sap found in the roots which colours the rootstock red (haima is Greek for blood and dôran means gift; wort is old English for a plant; Haemodorum is the Australian genus on which this family is based). It consists of 13 genera found in Australia, southern Africa and tropical America, the Australian representative most familiar to gardeners being Anigozanthos, the kangaroo's paw.
The genus Wachendorfia is endemic to southern Africa and occurs only in the Western Cape and Eastern Cape. It is a small genus of four species: Wachendorfia brachyandra, Wachendorfia multiflora (= W. parviflora), a very variable species, Wachendorfia paniculata (including Wachendorfia graminifolia, now sunk into this species), and Wachendorfia thyrsiflora. All but Wachendorfia thyrsiflora (which is evergreen) are winter-growing and summer-dormant.
The genus is named in commemoration of E.J. von Wachendorff, the 18th century professor of botany and chemistry at Utrecht. The specific name thyrsiflora means that it has flowers in a thyrse. A thyrse is an inflorescence with a racemose primary axis and cymose lateral axes, i.e. the main branch is ever-growing, producing new flowers all the time with the youngest at the top, and it has side branches which end in a terminal flower with any successive flowers behind it.
In strict terms, this does not apply to Wachendorfia thyrsiflora, as its inflorescence is not a thyrse but a panicle, which is an inflorescence with a racemose main axis and racemose lateral axes. I prefer a more romantic classical derivation from the Latin thyrsus, from the Greek thursos which is a rod or wand tipped with a pine cone, symbolic of Bacchus/Dionysus, which, gods of wine aside, is perfectly descriptive of the overall appearance of the inflorescence. The common names of bloodroot and rooikanol (red-rootstock), like the family name, refer to the red colour of the roots and rhizomes.
The pollinator of Wachendorfia thyrsiflora is unknown, and its pollination biology is a bit of an evolutionary puzzle. The flowers produce a generous amount of nectar which is easily stolen, with the thief not having to get anywhere near the pollen or stigmas in order to get at the nectar, so there is no apparent benefit to the plant. Furthermore, the stigma and anthers are too far apart for most insects, including the honeybee, to touch when visiting for nectar, and this rules them out as pollinators. The carpenter bee is a possible pollinator as it is large enough, or tabanid flies whose wings do touch the anthers, or any number of beetles that feed on the pollen, clambering over the flowers to get at the pollen and touching the stigmas in the process. To add to the puzzle, Wachendorfia has a peculiar form of floral enantiomorphy, i.e. they have left- and right-handed flowers that are mirror images of each other. Within a population there are flowerheads with flowers whose stigmas are bent sharply to the left and another has them bent to the right. Also, one of the stamens is bent in the direction opposite to the stigma. Enantiomorphy was thought to promote outcrossing but in Dilatris, also a southern African member of Haemodoraceae, there are left- and right-handed flowers on one flowerhead, and the function of this is not understood. In any event, someone or something does effect pollination and the resultant fruit is a 3-locular capsule containing three 5 x 3 x1 mm semi-circular black seeds. They are hard but light in weight, and are densely covered in short coarse hairs which give the seeds a fuzzy outline. They also float on water and, given the riverine habitat of the plant, this is probably an adaptation for water dispersal.
The rhizomes can be used to make a reddish brown dye.
Growing Wachendorfia thyrsiflora
Wachendorfia thyrsiflora is an easy plant to grow and is ideally suited to marshy or swampy conditions in full sun or semi-shade, but will also grow in soil that is not waterlogged provided it gets ample water, particularly during winter and spring. A generous mulch of compost is also very beneficial. It is evergreen if it is given water all year round, but if given total summer drought it may die down and go dormant, but it is best not to let it dry out during summer. Wachendorfia thyrsiflora is invaluable in difficult permanently wet areas, is an attractive addition to the water garden where it can be planted at the water's edge or where the water overflows, and it makes an excellent backdrop to the herbaceous border. It looks good mixed with Dietes bicolor, the yellow wild iris, and provides an interesting colour combination when mixed with the blue flower spikes of Aristea major. In a water garden or permanently wet area, it can be used with a variety of other plants also suited to this environment such as Elegia capensis, Cyatheadregei (tree fern), Zantedeschia aethiopica (arum lily), Watsonia meriana, Cyperus papyrus (papyrus), etc. It multiplies rapidly and can be left undisturbed for several years without flowering being adversely affected. Wachendorfia thyrsiflora is not hardy to severe frost, but should be able to survive outdoors in USDA Zone 10 (-1 °C / 30 °F minimum), possibly even Zone 9 (-7 °C /20 °F minimum) if it is given a protected spot. It is not subject to any serious pests or diseases.
Propagation of Wachendorfia thyrsiflora is by seed and division. Seed is sown in autumn, in deep (minimum 10 cm) trays in any good seedling mix, and kept permanently moist. Seedlings will be ready for transplanting at the beginning of their third season, when they can be potted into individual pots/bags or planted into the garden. Flowering can be expected from their fourth season. Wachendorfia thyrsiflora multiplies rapidly, new rhizomes are produced annually, and it also has the ability to send out stolon-like outgrowths from the main rhizome, sometimes extending sideways for up to several metres, which are able to form new plants at the tip. Clumps are best divided after the flowering period in early summer and replanted immediately.
Kirstenbosch National Botanical Garden
Plant Type: Bulb, Perennial
SA Distribution: Eastern Cape, Western Cape
Soil type: Sandy, Loam
Flowering season: Spring, Early Summer
PH: Acid, Neutral
Flower colour: Yellow
Aspect: Full Sun
Gardening skill: Average