Oxalis triangularis (purple shamrock) grows from small, scaly underground storage organs that are botanically a tuberous rhizome, though they’re very commonly sold and searched for as “bulbs” – both terms are widely used in the plant trade, but “tuberous rhizome” is the accurate botanical description. Whichever word you use, the growing routine is the same: plant shallow, keep it evenly moist while it’s in leaf, and let it rest when it dies back.
Planting the Rhizomes
Plant the rhizomes shallow – about 2-5cm (1-2in) deep – in a pot with drainage holes, spaced a couple of centimetres apart if planting several together for a fuller clump. The small, scaly rhizomes can be easy to lose track of in loose soil, so plant them in a marked spot or a dedicated pot rather than scattering them into a mixed border.
Soil and drainage
Use a rich mix that holds some moisture but still drains freely – ordinary potting mix with added organic matter works well. Good drainage matters for the rhizomes specifically, since sitting in wet soil for long periods invites rot.
Watering while in leaf
Keep the soil evenly moist through the active growing season, watering deeply and letting the surface start to dry before watering again. Reduce watering as the foliage begins to yellow and die back – this is the plant entering dormancy, not a sign of a problem.
Dormancy: what to do when the foliage disappears
Oxalis triangularis is a geophyte that naturally dies back for a rest period each cycle, and it’s normal for the entire pot to look bare afterwards. During dormancy, keep the rhizomes cool and nearly dry – don’t keep watering a pot with no leaves, since a dormant rhizome kept wet is prone to rot. New growth signals the end of dormancy; resume normal watering once shoots reappear.
Division and storage
The easiest way to propagate is by separating the small rhizomes once the plant is dormant and the foliage has died back. They can sit deeper in the soil than expected and are easy to miss, so lift the whole root mass carefully rather than searching for individual rhizome pieces in place. If you can’t cleanly separate them, lifting and replanting the whole clump is a reliable fallback. Cleanly separated rhizome pieces can also be stored in a cool, dry place until you’re ready to replant.
Common mistakes
The most common error is continuing to water heavily after the foliage has died back, which rots the resting rhizomes. The second is planting too deep – these rhizomes are small and shallow-rooted, and a deep planting can delay or prevent emergence.
Quick questions
Are oxalis “bulbs” really bulbs? Not quite – botanically they’re a small, scaly tuberous rhizome, though “bulb” (and sometimes “corm”) is the common trade and search name.
My oxalis triangularis lost all its leaves – is it dead? Almost certainly not – this is a normal dormant rest period. Keep the pot cool and nearly dry and new growth should return.
Can I grow oxalis triangularis from seed instead of from a rhizome? Yes, seed produces true plants of the species, but it’s much slower to reach a useful size than starting from a rhizome piece.
Related guides
{“@context”:”https://schema.org”,”@type”:”Article”,”headline”:”Growing Oxalis Triangularis from Bulbs (Tuberous Rhizomes)”,”description”:”How to plant and care for Oxalis triangularis (a tuberous rhizome, commonly sold as “bulbs”): planting depth, watering, dormancy, and dividing the rhizomes.”,”mainEntityOfPage”:{“@type”:”WebPage”,”@id”:”https://www.growplants.org/gardening/oxalis-triangularis-bulb-care”},”author”:{“@type”:”Organization”,”name”:”GrowPlants”,”url”:”https://www.growplants.org”},”publisher”:{“@type”:”Organization”,”name”:”GrowPlants”,”url”:”https://www.growplants.org”},”datePublished”:”2026-09-12T00:55:18+00:00″,”dateModified”:”2026-09-12T08:40:34+00:00″}
For the equipment that makes propagating easier (heat mats, humidity domes, rooting hormone), see our propagation equipment guide.
