Asplenium antiquum ‘Osaka’

A Japanese bird’s-nest fern with two horticultural placements

The available breeding record does not identify who first selected ‘Osaka’. The documented history of its descendant ‘Crispy Wave’ treats ‘Osaka’ as an existing, unpatented Asplenium nidus cultivar and records that Haruo Sugimoto selected a naturally occurring mutation of it on Yaku Island in 1961. Decades of spore propagation from that line preceded the selection of ‘Crispy Wave’ in 2000.

Contemporary horticultural trade commonly places ‘Osaka’ under the East Asian species A. antiquum. The two botanical labels reflect unresolved horticultural identification rather than two separately documented cultivars. Under the current product name, A. antiquum is native from south-eastern China through Taiwan, southern Japan and Korea.

Moisture and airflow for healthy fronds

Leaf care

Asplenium antiquum ‘Osaka’ carries strongly ruffled frond margins. Remove a spent outer frond with a clean basal cut.

Humidity and airflow

Aim for moderate to high humidity around Asplenium antiquum ‘Osaka’. Average room air may be adequate, but raised frond edges dry sooner in centrally heated conditions.

Light

Give Asplenium antiquum ‘Osaka’ useful filtered daylight beside an east or north-east window. Rotate only after a new frond has hardened, since its shape is fixed while it unfurls.

Watering

Keep Asplenium antiquum ‘Osaka’ lightly and evenly moist. Once the surface begins to dry, water thoroughly around the edge of the crown and allow all excess to escape.

Substrate and roots

Pot Asplenium antiquum ‘Osaka’ in a loose fine-textured blend of quality substrate, small bark and perlite or pumice. Use a modest pot with an open drainage hole, keep all central growth above the surface and flush hard-water and fertiliser salts before they mark the frond edges.

Temperature

Keep temperature changes gradual and protect the plant from cooling vents, particularly while a new frond is still expanding.

Problems and solutions for Asplenium antiquum ‘Osaka’

• Narrow fronds have strongly rippled margins: Regular green waves along both edges are the normal ‘Osaka’ feature, not leaf curl. Stress is more likely when the margin is also brown, bleached or collapsing.
• New fronds become flatter or less ruffled: A change in the newest leaves can follow weak light or root stress. Give bright filtered light, keep the root ball evenly moist and judge the next growth; existing fronds will not change shape.
• A new frond emerges uneven or torn: The rolled leaf may have been marked by handling or a dry spell while it was expanding. Do not pull or trim live tissue from the centre; stabilise moisture and assess the following frond.
• The centre turns brown and no frond advances: Crown rot is likely if the growing point is soft or smells sour. Stop pouring water into the nest, clear only loose dead material and keep the root zone moist but not saturated.

Asplenium antiquum ‘Osaka’ is non-toxic to cats and dogs

• This plant is non-toxic to cats and dogs.
• Its effects on people are unclear, so keep it away from young children who may chew it.
• Eating a large amount can still cause an upset stomach. Seek medical or veterinary advice if symptoms continue.

Where does the name Asplenium antiquum come from?

Asplenium comes from the old Greek name asplenon, linked with splen, spleen. The Latin epithet antiquum means old or ancient.

Carl Linnaeus established the genus Asplenium in 1753 in Species Plantarum, page 1078.

Tomitarô Makino first described Asplenium antiquum in 1929 in Journal of Japanese Botany, volume 6, page 32.