Pinguicula primuliflora

Telling it apart from its neighbors

Six butterworts grow in the southeastern United States ^{[4, 3]}, and Donald Schnell warned that flowers are usually needed to name any one of them with certainty ^[4]. P. primuliflora is easy once it blooms. Schnell describes the flower as very distinctive, with a white center and rose-colored petal tips ^[4]. Bob Ziemer calls the flowers pale purple, solitary, spurred and trumpet-shaped, with two lobes ^[2]. Either description separates it from the large yellow flowers of P. lutea and the dark-veined violet flowers of P. caerulea ^[4], which are covered on the Pinguicula page.

Out of flower, look at the leaf tips. Plants bud new rosettes from their leaf tips, so a wild colony often forms a cluster of plants of different sizes, the larger ones toward the middle, like hens and chicks. Schnell treats this budding as a fairly specific trait of the species in nature, although several other species occasionally do it in cultivation ^[4]. DNA work places P. primuliflora in section Isoloba, alongside P. pumila and P. lutea ^[9].

Shady streams on the Gulf Coastal Plain

This is a plant of moving water. NatureServe describes it in shallow, usually flowing water around springs, on boggy banks of small streams and in swamps, and only rarely in ditches ^[3]. Schnell found it in wet, usually shaded places such as streamsides or beneath tufts of bunch grass and sedges, and notes that it is often hard to find when not in flower ^[4]. Native records come from Alabama, Florida, Georgia and Mississippi ^[1].

Where it occurs it is often locally common, though plants without flowers are easily overlooked in surveys. NatureServe lists 26 known occurrences in Mississippi, warns that little habitat may remain in Florida and Alabama, and describes it as very rare to extinct in southwestern Georgia. The species depends on a steady water supply, and drainage, housing development and forestry practices threaten its sites ^[3]. Unlike P. ionantha, which has the smallest range of the six in the Florida panhandle ^[4], it is not listed under the Endangered Species Act ^[5].

Plantlets at the leaf tips

Ziemer writes that it is one of the carnivorous plants propagated for the mass market and sold in most garden centers, that beginners grow it easily, and that it readily makes plantlets on its leaf margins ^[2]. Mitsuaki Ban, who grew it in Japan, notes that growers rarely bother to collect its seed for exactly this reason ^[8].

That habit also guards against a weakness of the group. ICPS describes warm temperate butterworts as short-lived perennials that need hand pollination and tend to flower themselves to death, so it advises pollinating with a small brush and saving seed ^[7]. With P. primuliflora, leaf-tip plantlets offer a second way to keep a plant going.

‘Rose’, a double-flowered selection

In May 1995 Ban found a seedling with double flowers among his plants in an unheated cold frame, where bees had set seed on about 30% of the flowers ^[8]. Ban considered it a spontaneous mutant seedling, while Ziemer calls it a variant or possibly a hybrid ^{[8, 2]}. The name refers to the rose-like flower. Healthy plants carry more than five layers of petals, and all of about 60 plants propagated from it kept the trait. Ban thought the extra petals took the place of the pistil, because only stamens remained once he stripped the petals ^[8]. The double flowers are sterile, so ‘Rose’ is propagated only vegetatively, from leaf-tip plantlets; apart from the flowers it looks like any other P. primuliflora ^[2]. It is now grown around the world ^[2].

Growing it

The ICPS guide for warm temperate butterworts covers this species ^[7]:

• Mix: 3 parts peat, 1 part silica sand and 1 part perlite, or pure peat in some conditions. See carnivorous plant soil.
• Water: keep it damp at all times with pure water; see water.
• Where: within its native region it can grow outdoors, with protection during freezes. It also does well in a terrarium; see terrariums and humidity.
• Seed: germinates in 2 to 4 weeks above 15°C (60°F) on constantly damp soil. If cyanobacteria or moss overgrow the seedlings, move them to fresh medium. See sowing seeds.

Timing matters if you want seed. Ban points out that butterworts of this group kept in heated frames flower around February, when no pollinating insects are about, so they set little seed unless pollinated by hand ^[8]. Plants kept cool flower in spring, close to their natural season.