Oxalis vulcanicola 'Sunset Velvet': care, light and hardiness

To care for Oxalis Sunset Velvet, give it plenty of light, water when the top of the potting mix has dried out, and bring it indoors before frost: these three steps will keep its foliage orange and dense. Its full name is Oxalis vulcanicola 'Sunset Velvet' (sometimes written as Oxalis spiralis subsp. vulcanicola), an orange oxalis with a spreading habit, very different from the bulbous purple shamrock.

“Velvet” means velvety and “sunset” refers to the setting sun, alluding to its warm colors. For the genus and its most widely grown species, see our Oxalis triangularis (purple shamrock) guide; for its purple-hued cousin, see our Oxalis Plum Crazy profile.

🌿 Why does Oxalis Sunset Velvet foliage change color?

Oxalis Sunset Velvet's color depends on light and the season. According to the RHS (Royal Horticultural Society) profile for 'Sunset Velvet', its leaflets are orangey pink in spring, become greener in summer, then turn deep magenta in autumn, on reddish stems.

For the species, the RHS notes in its Oxalis vulcanicola species profile that the green leaves turn pinkish purple in the sun and that the plant turns its foliage toward the light.

So an Oxalis vulcanicola that looks greener in midsummer is not sick; pale foliage and elongated stems year-round, on the other hand, indicate insufficient light.

🔎 Oxalis Sunset Velvet at a glance

According to Plants of the World Online (POWO), the database of the Royal Botanic Gardens, Kew, the accepted name is Oxalis vulcanicola Donn.Sm., published in 1897; Oxalis spiralis subsp. vulcanicola, a combination published by Lourteig in 1981, is a synonym, as is Xanthoxalis vulcanicola.

POWO places its native range from southeastern Mexico (Chiapas) to western Panama, via Guatemala, El Salvador, and Costa Rica, in subtropical habitats, with no mention of South Africa. The RHS lists 'Sunset Velvet' under Oxalis vulcanicola, with Oxalis 'Sunset Velvet' and Oxalis spiralis subsp. vulcanicola 'Sunset Velvet' as synonyms.

We sell it as Sunset Velvet; the RHS also maintains a separate profile for a cultivar named 'Molten Lava', and no source consulted establishes that the two names refer to the same plant.

📋 Quick care guide

Essential growing tips, all in one glance.

📍 Where to place Oxalis Sunset Velvet: indoors or outdoors?

Oxalis Sunset Velvet can be grown outdoors in warm weather or indoors, as long as it gets enough light. The RHS recommends full sun or partial shade, with a south-, east-, or west-facing aspect, in well-drained soil, and also suggests growing it in a conservatory or on a windowsill.

Its hardiness rating of H2 (1 to 5 °C) means it tolerates cold but not freezing: in France, grow it in a pot outdoors after the last frost and bring it indoors before the first frost.

Indoors, the University of Wisconsin–Madison horticultural extension recommends a sunny window and relatively cool conditions for Oxalis, with daytime temperatures not exceeding around 24 °C (75 °F).

☀️ Indoors: Bright south-, east-, or west-facing window, a relatively cool room, away from radiators

🌤️ Outdoors: Planter, hanging basket, or patio pot in gentle sun or partial shade, from the end of frost season until autumn

🚫 Avoid: Frost, planting in the ground in a region with cold winters, and dark corners that cause the leaves to turn green and stems to become leggy

🪴 Planting and repotting Oxalis vulcanicola: what potting mix should you use?

Oxalis vulcanicola needs potting mix that never stays waterlogged. The RHS recommends well-drained, sandy, or humus-rich soil and, for growing under cover, an equal-parts mix of loam, leaf mold, and grit.

In practice, a light potting mix amended with a drainage material works well: our all-purpose growing medium enriched with biostimulants makes a good base, and our article on the difference between potting soil and growing medium will help you prepare the mix.

Repot in spring, when the roots fill the pot; Iowa State University Extension notes that Oxalis often does better when slightly pot-bound.

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✂️ Oxalis vulcanicola care: watering, fertilizer, and pruning

When watering Oxalis vulcanicola, aim for potting mix that stays moist but well-drained, as the RHS recommends. The University of Wisconsin advises keeping Oxalis soil barely moist, never wet, and allowing it to dry slightly between waterings: check with your finger rather than following a schedule.

As for fertilizer, NC State Extension's Oxalis genus profile (North Carolina State University) and the University of Wisconsin recommend feeding monthly during the growing season only; our liquid fertilizer for houseplants should be applied at a low dose.

The RHS does not require pruning; simply pinch back any overly long stems to keep the plant bushier. There is no need to mist it: see our article on misting.

💧 Watering: Water when the top of the potting mix has dried out; empty the saucer after each watering

🌱 Fertilizer: Once a month from the start of new growth until late summer; none in winter

🔹 Pinching: Cut back leggy stems to encourage denser growth; optional according to the RHS

🔹 Spent flowers: Remove them if you like, to keep the plant looking tidy

👀 Watch for: Aphids and spider mites indoors; slugs and snails outdoors

🍂 Dormancy and winter: why is Oxalis vulcanicola losing its leaves?

Unlike Oxalis triangularis, Oxalis Sunset Velvet does not require a dramatic annual dormancy, but it may slow down and lose some of its leaves. The RHS describes the species as a deciduous perennial with fleshy stems: leaf loss, for example after a cold snap, does not necessarily mean the plant is dying.

For the genus, NC State notes that many species go dormant in summer after flowering, with new growth appearing in 1 to 3 months, while Iowa State advises keeping them cool, in the shade, and almost dry until new shoots appear. In winter, keep it above 5 °C, in a bright spot, and water less often.

📅 Seasonal care calendar

🌱 Propagating Oxalis Sunset Velvet: division and cuttings

The RHS lists two propagation methods for Oxalis Sunset Velvet: division and seed. Division is the easiest method in spring: take the plant out of its pot, split the clump into two or three sections with roots, then pot each one in well-draining mix.

Stem cuttings, often tried with this creeping plant, are not listed by the RHS: take a healthy section in spring, but success is not guaranteed. For help choosing a medium, see our guide to propagating in water or potting mix.

🐛 Common problems: causes and solutions

The main problems affecting Oxalis Sunset Velvet are insufficient light, overwatering, and frost. The RHS lists slugs, snails, vine weevil larvae, and rust as pests and diseases affecting the species; NC State lists aphids, spider mites, whiteflies, leaf spots, and root rot from overwatering for the genus.

If the stems turn black at the base, see our root rot guide.

🌸 Our Oxalis varieties

Sunset Velvet is not the only Oxalis vulcanicola in cultivation: the RHS also describes pinkish-purple variegated foliage, yellow flowers and the same H2 hardiness rating in its 'Plum Crazy' profile. Oxalis triangularis, on the other hand, is a different species: a purple shamrock with underground organs and white to pale pink flowers that goes through a true annual dormancy (see our Oxalis triangularis profile). Here are the Oxalis plants in our collection for comparison.

🎨 In a hanging basket or planter: which plants pair well with Oxalis Sunset Velvet?

Its spreading, semi-trailing habit makes Oxalis Sunset Velvet a good choice for the edges of containers: in a hanging basket, window box or at the edge of a planter. The RHS recommends the species for patios, rock gardens, containers and conservatories.

It creates a lovely contrast with dark foliage, such as that of Oxalis triangularis, or with the green leaves and purple centers of Oxalis deppei. For more ideas for cascading greenery, browse our guide to trailing and hanging houseplants.

⚠️ Is Oxalis Sunset Velvet toxic to cats and dogs?

Yes, keep it out of pets' reach. The ASPCA (American Society for the Prevention of Cruelty to Animals) Shamrock Plant profile covers the Oxalis genus (Oxalis spp.), which includes Oxalis vulcanicola. It classifies these plants as toxic to dogs, cats and horses because they contain soluble calcium oxalates.

Signs listed include kidney failure (rare in dogs and cats), tremors and drooling. NC State notes that all parts of the plant have toxic potential, with serious effects generally associated with large amounts.

If you live with a curious pet, place it in a hanging basket, or choose from our list of plants that are non-toxic to cats and our plants that are safe for dogs.

✅ Our expert tips for success

Four simple steps will help your Oxalis Sunset Velvet thrive: give it plenty of light to maintain its orange foliage, water when the top of the potting mix has dried out, feed it monthly while it is growing, and shelter it as soon as frost threatens, as the RHS does not consider it frost-hardy. Expect it to turn green in summer and lose a little foliage in winter.

Keep it out of pets' reach and let it trail from a hanging basket to enjoy its growth habit.