The great indoors
Jess Snowball takes a look at the unfussy house fern Phlebodium aureum
Ferns have an enduring appeal to houseplant enthusiasts. Pteridomania or Fern-Fever was the first houseplant craze among Victorians, with fern motifs appearing everywhere. Plants were no longer labelled exclusively for the academic and the amateur naturalist was born. Ferns have always appealed; the exquisite detail of their fronds and varying green tones radiate a raw, forestry feel.
Polypodiaceae is among the largest of the fern families, representing more than 60 genera. Within this Phlebodium aureum, the blue star fern is one of four Phlebodium species, which originate from the tropical and subtropical regions of the Americas and are easily differentiated. All are exclusively epiphytic; they can be found clinging to parts of other plants high up in the canopy of forests. Growing to around a metre in height Phlebodium aureum differs slightly from plants we more commonly think of as ferns, such as Dryopteris filix-mas, due in part to its colour. Its wavy blue-green fronds vary between silver, grey and palest green and appear from creeping, hairy rhizomes (modified stems). The fronds are lobed and can grow up to 40cm. The round, bright-orange sori (clusters of sporangia, the structures that produce and contain spores) are arranged in two rows on each side of the midrib on the underside of the fronds.
This is a very tough plant. I have grown a blue star fern in the open terrarium (of a pint glass) with almost no growing medium and only occasional watering. Five years on, it’s thriving. Another, which is growing terrestrially in a pot, with sporadic waterings, is equally happy. The fern’s epiphytic habit and rhizomatous form allow it to succeed in unfavourable environments. Cultivation
Phlebodium aureum are extremely easy to grow and are generally unfussy of their conditions. Grow them in a bright spot with little or partial direct sun. They will tolerate sun a little more than most other ferns. Water generously once you notice the pot drying out, continuing until water runs out of drainage holes at the bottom. Alternatively submerge the plant in a sink or bucket of water until all the air bubbles (old oxygen) have been forced out from the soil and allow it to drain. Take care not to over water, Phlebodium do not like to be constantly soggy. When choosing a potting mix, bear in mind the plant’s epiphyte habit, growing on other plants in its natural habitat, and choose a very loose, freedraining medium. Bark, grit and pumice or an orchid mix work well. When repotting, it’s crucial not to bury the hairy rhizomes below the surface of the soil. They have trichomes (tiny hairs), which capture water from the air, that also send out roots and shoots.
Repot when you notice the rhizomes and roots are becoming crowded and pot bound but generally, epiphytes can be left for a while. Try to repot in spring or summer if required and if root damage is inevitable, water well afterwards. Feed during the growing season at a low dosage. There is no need to feed during the winter at all, as these aren’t hungry plants and you could risk damage.
Propagate Phlebodium aureum by division. While repotting, gently tease out roots from the root ball. The number of divisions depends on the size of the parent plant and you can create as many sections as there are sufficient roots, rhizomes and leaves to support. Pot up each section in a free-draining mix and water in well. If the plant goes into shock remove any dying leaves and keep the plant in a warm, humid and light location. Wrapping the potted division in a clear plastic bag tied at the top with string creates humidity, reducing critical water loss. Remove the bag after a few days. Alternatively, don’t be afraid to remove a few healthy leaves to balance out the loss of roots – again this lowers the amount of water lost.
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Jess Snowball is glasshouse manager at the Chelsea Physic Garden, London.