Thaumatophyllum xanadu 'Lemon'

Where the species behind Thaumatophyllum xanadu 'Lemon' grows naturally

Thaumatophyllum xanadu is native to southern Brazil and Paraguay. It grows in warm areas with a distinct dry season, forming a low, branching plant directly in the ground.

Rain falls regularly, with drier periods between rains. Wild plants stay low and broad as stems branch close to the ground.

Indoor care for Thaumatophyllum xanadu 'Lemon'

• Light: Give 'Lemon' plenty of bright filtered light. Brief gentle sun is suitable when introduced gradually. Fresh yellow leaves can develop brown marks if the increase in sun is too sudden.
• Watering: Allow the upper potting mix to dry a little between waterings while some moisture remains deeper in the pot. Water thoroughly and let the excess drain.
• Potting mix: Use a well-draining potting mix that still holds some moisture; fine bark with pumice or perlite works well.
• Temperature and humidity: Warm indoor conditions and normal household humidity are usually suitable.
• Feeding: Feed lightly to moderately with a complete houseplant fertiliser while new leaves are forming.
• Growth and position: The short stems hold the plant upright. Allow room around the pot and turn it occasionally if new growth leans strongly toward one light source.
• Repotting: Repot once the roots are tightly packed or the pot starts drying much faster than usual. Keep the base at the same depth.
• Propagation: Use a rooted section of the plant or a stem cutting with a healthy bud from the same plant to keep the lemon-to-chartreuse colouring.

Common problems with Thaumatophyllum xanadu 'Lemon'

• New leaf stalks grow longer, leaves sit farther apart and the new colour looks darker: Mature leaves naturally deepen toward chartreuse. Longer leaf stalks and wider spacing on new growth can indicate too little light. Check the newest leaves first, then increase bright filtered light gradually if needed.
• Yellow-green areas develop crisp brown marks: Strong sun, a dry potting mix or fertiliser build-up can damage the leaves. Correct the cause and check the next leaves for brown marks.
• Lower leaves yellow while the potting mix stays wet: Prolonged wetness can stress the roots and lead to rot. Check the roots before watering again. Remove rotten roots with clean scissors, cutting back to firm healthy roots. Discard what you remove and repot in fresh, well-draining mix. The root rot guide covers the remaining recovery steps.
• White cottony patches, sticky residue or fine pale speckles appear near the centre: These signs can indicate mealybugs, scale or mites. Check both sides of the leaves and around the stems. Keep the plant away from nearby plants while treating it, and follow the product label. The mealybug guide explains identification and repeat treatment.

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.