The flowers of Utricularia sandersonii are small enough to miss at a distance and distinctive enough to remember once seen. Two upright lobes give them their familiar “bunny ears”, held over a low green colony. It makes an inviting subject for close-up photography, but the flowers tell only part of its story. This is also a plant of wet rock surfaces, with a finely organised network of stolons and miniature traps.
Understanding that habitat makes its care more intuitive. Moisture must reach the plant consistently, while its visible growth has access to light and air. This profile separates botanical evidence from a practical starting routine for cultivation.
Identity and botanical relationships
Kew accepts the name Utricularia sandersonii Oliv., first published in 1865. Its native range extends from the Eastern Cape to northern KwaZulu-Natal in South Africa. Kew treats U. treubii and U. sandersonii var. treubii as synonyms. An old label bearing either name should be preserved in the plant’s history even when the current accepted name is added. Kew: name, range and synonyms.
It belongs to Lentibulariaceae and is conventionally placed in section Calpidisca within subgenus Bivalvaria, alongside U. livida. Sectional boundaries remain a subject of research: a 2017 study found the traditional Calpidisca grouping to be paraphyletic, meaning it did not contain all descendants of its shared ancestor. The section remains a useful literature reference when its treatment is stated. Rutishauser, 2016; Westermeier and colleagues, 2017.
Leaves, flowers and scale
SANBI’s regional flora accounts describe a perennial plant with wedge-shaped, obovate or fan-shaped leaves. The upper corolla lip divides deeply into two spreading lobes, while the lower lip is approximately circular. Flowers can be white, pale mauve, pale pink or blue, with darker markings and sometimes yellow on the palate. A simple inflorescence of 20–70 mm is reported in the Eastern Cape flora. SANBI descriptions.
The familiar cultivated appearance is a white flower with pale blue markings and the two conspicuous upper lobes. The RHS uses those features in its horticultural description. To document an unknown plant, include a side view of the spur as well as the recognisable front view. A flower’s outline carries more information than a colour label alone. RHS plant profile.
A plant of wet rock surfaces
“Lithophytic” means growing on rock. Here it refers particularly to wet surfaces, sometimes vertical ones. SANBI also records damp soil and epiphytic occurrences in forest habitats. These descriptions explain why U. sandersonii appears in both terrestrial growing guides and discussions of rock-dwelling bladderworts: the categories can overlap. SANBI habitat accounts.
SANBI’s account of Pondoland-Ugu Sandstone Coastal Sourveld associates the species with wet depressions and rock pools in a landscape of acidic, nutrient-poor sandy soils. A pot need not reproduce an entire cliff face, but the habitat is a useful reminder that exposed rock and reliable moisture can occur together. A decorative stone that repeatedly dries out does not reproduce the same conditions. SANBI vegetation account.
What is happening below the flowers?
A developmental study illustrates slender runner stolons bearing foliage and traps. Most traps occur along the stolons, with others developing on the lower surfaces of leaf structures. This is why an apparently simple green mat contains much more than its visible blades. Illustrated plant architecture, Rutishauser, 2016.
Microscopy of U. sandersonii has also revealed a cuticular velum and mucilage-producing tissues at the trap entrance. These specialised structures belong to its microscopic carnivorous apparatus. They do not require the grower to place insects onto the leaves or flowers. Keep observation gentle: repeatedly peeling back a colony for a view of its traps defeats the purpose of establishing it. Płachno and colleagues, 2019.
Starting cultivation
The RHS recommends permanently moist pots, pure or rainwater, and propagation by division or seed. Its H2 hardiness rating is framed for UK conditions and specifically excludes freezing. For an Australian collection, use that as a reason to provide frost protection, not as an optimum growing temperature. RHS cultivation and hardiness guidance.
For a first pot, our suggested approach is deliberately easy to observe:
- Use a simple container. Choose a small plastic pot and a separate shallow water tray. Put the label where it will remain readable as the colony spreads.
- Choose an unfertilised medium. Equal parts peat and suitable sand is a published terrestrial-bladderwort mix. Avoid ordinary enriched houseplant compost. Wet the medium before placing the plant.
- Keep water available. Refill with low-mineral water before the colony dries. Set the tray level below the top of the medium so foliage and flower stalks remain exposed.
- Provide bright, moderated conditions. Begin with bright filtered light and airflow, then adjust gradually according to growth. Avoid an abrupt move from protected culture into hot afternoon sun.
The mix and emphasis on light and air are consistent with the New England Carnivorous Plant Society’s general terrestrial guide. That grower account suggests approximately 21–29°C for warm-growing terrestrial bladderworts; this is group-level guidance, not a measured optimum for every U. sandersonii clone. A stable, frost-free position is more useful than chasing a single temperature. NECPS care account.
Flowering and everyday observation
Do not make a flowering deadline the first test of success. Start by looking for new foliage extending beyond the original piece. Record the pot from the same angle every week so small changes are visible. If growth is healthy but flowers are absent, review light, recent disturbance and temperature before changing the watering regime.
Regional flowering records vary; they do not promise blooms in a fixed Australian month. Keep a flowering record for your own clone. Regional flowering records.
Informal descriptions such as “blue form” may help a grower distinguish accessions, but colour wording alone does not establish a botanical variety or registered cultivar. Retain the supplier’s exact label, add the acquisition date, and keep a photograph of its flowers. Do not silently convert a trade description into a formal name.
Dividing an established colony
Division is an accessible method because a spreading colony can be moved in small pieces with some medium attached. Place the piece against fresh wet medium rather than burying all its visible foliage. Prepare the new label first, and record its connection to the parent pot. The ICPS describes both division and partial renewal of old medium for cultivated terrestrial bladderworts. ICPS growing guide.
Keep different accessions separate during the process. In one nine-month containment experiment, U. sandersonii did not escape even from the unscreened control pot. That narrow observation does not establish that it can never spread into neighbouring pots. The study tested vegetative escape, not every route of contamination. Our practical recommendation remains separate trays, clean working space and an identity check before sharing divisions. Cahill, 2007.
When something looks wrong
Use a short investigation rather than a quick diagnosis. If a patch browns, check whether the medium dried, whether the pot overheated and whether the change followed repotting. If the surface becomes crowded with other growth, photograph it before removing anything so unfamiliar bladderwort leaves are not mistaken for weeds. Compare healthy and affected areas under the same light.
For a newly received plant, keep its arrival condition separate from later changes. A photo, water-source note and short record of placement provide better evidence than “it was fine last week”. Where identification is uncertain, retain the provisional label until the plant flowers or a specialist can examine it.
Conservation and place in the collection
SANBI identifies U. sandersonii as South African endemic and lists it as Least Concern in its species record. Choose cultivated material with a clear history. SANBI species record.
In this series: compare the companion U. livida profile, then return to “Terrestrial Utricularia” for the shared growing framework. Together, these species show how close botanical relatives can reward different attention to habitat and identification.
Research checked 22 September 2026. Practical recommendations are starting points, not results of a Nano Nursery cultivation trial.
