Thaumatophyllum xanadu 'Lemon'

Thaumatophyllum xanadu 'Lemon': origin and background

‘Lemon’ is a cultivated form with no separate wild range. Thaumatophyllum xanadu comes from southern Brazil and Paraguay, where it grows close to the ground in seasonally dry tropical vegetation. Its compact habit suits warm indoor conditions, bright filtered light and a free-draining mix that dries partly between waterings.

Thaumatophyllum xanadu 'Lemon': plant care

Light

Bright indirect light keeps ‘Lemon’ compact and its chartreuse colour clear. Gentle morning sun can be introduced gradually, but intense direct light can bleach or crisp leaves that already contain less chlorophyll than a green form.

Water

Water thoroughly after the upper layer of the mix has dried, then allow free drainage. Avoid both a permanently damp centre and repeated severe wilting, which can leave the compact plant with yellow lower leaves and dry margins.

Potting mix

Use a medium-textured aroid mix with fine bark, perlite or pumice and enough organic material to hold some moisture. Use a drainage hole and keep the crown at its original level when repotting.

Temperature and humidity

Normal warm rooms around 18–27 °C are suitable, with no cold draughts or contact with winter glass. Average room humidity is usually enough, though a modest increase can help tightly furled leaves open cleanly.

Feeding and repotting

Apply dilute balanced fertiliser while fresh leaves are appearing and reduce it when growth slows. Move the plant into a slightly larger pot only when the roots are crowded, so the mix continues to dry evenly.

Keeping the plant balanced

This compact, self-heading selection needs no pole. Give it light from several angles or rotate the pot in small increments, remove spent leaves at the base, and allow enough side room for the plant to widen.

Propagation

Divide a mature plant so each section retains roots and at least one growing bud. Pot divisions at the same depth in airy mix and keep them warm and lightly moist until a new leaf appears.

Common problems with Thaumatophyllum xanadu 'Lemon'

The plant loses its compact shape

Longer leaf stalks and a looser shape commonly develop when light is too low or strongly one-sided. Shift the plant gradually into brighter filtered light and rotate the pot so the compact crown develops more evenly.

Leaves bleach or crisp near the window

This plant is naturally yellow-green, but dry pale patches on the exposed side are damage, not normal colour. Filter intense direct sun or move the pot farther from hot glass; scorched areas will not regain its colour.

Several lower leaves turn yellow

Check whether the lower mix is still wet before assuming the plant is thirsty. Soft brown roots indicate rot and should be removed before repotting in fresh airy potting mix; one firm, ageing lower leaf can simply be cut away when fully yellow.

A new leaf catches and tears

A leaf that fails to release may follow dry air or an uneven watering cycle. Raise the room humidity slightly, keep the roots from swinging between extremes and let the leaf open by itself rather than pulling the lobes apart.

Pests settle inside the compact crown

Inspect the compact centre, leaf-stalk bases and undersides for bumps, white wax, fine pale dots or webbing. Move it away from other plants, clean the crowded centre carefully and repeat the chosen pest treatment according to its directions.

Thaumatophyllum xanadu ‘Lemon’ is toxic to people and pets

• Keep this plant away from children, cats and dogs.
• Its leaves and stems contain insoluble calcium oxalate crystals, which can irritate the mouth, throat, skin and eyes.
• Chewing may cause burning pain, drooling, swelling, vomiting or difficulty swallowing. Contact a veterinarian or medical professional after exposure, especially if swelling or breathing problems occur.

How did the name change from Thaumatophyllum xanadu to Philodendron xanadu?

Thaumatophyllum means ‘wonder leaf’.

Heinrich Wilhelm Schott established the genus Thaumatophyllum in 1859 in Bonplandia (Hannover), volume 7, page 31.

Thomas Bernard Croat, Simon J. Mayo, and Julius Boos first described it as Philodendron xanadu in 2003 in Aroideana, volume 25, page 63. Cassia Mônica Sakuragui, Luana Calazans, and Simon J. Mayo later placed it in Thaumatophyllum as Thaumatophyllum xanadu in 2018 in PhytoKeys, volume 98, page 65.

Cassia Mônica Sakuragui, Luana Calazans and Simon Mayo revived Thaumatophyllum for this group in 2018 in PhytoKeys, volume 98. Kew’s World Checklist treats Thaumatophyllum xanadu as a synonym of Philodendron xanadu. Both names are still encountered.