The Webster Viridarium
It doesn’t have to be St. Patrick’s Day to enjoy the charm of the shamrock plant.
Shamrock plants, commonly sold as “shamrocks” (especially around St. Patrick’s Day), are not true shamrocks or clovers. They belong to the Oxalis genus (of the wood sorrel family, Oxalidaceae), and are often referred to as false shamrocks, purple shamrocks, or simply oxalis.
Legend holds that St. Patrick used the three-leafed clover to explain the Holy Trinity—Father, Son, and Holy Spirit—to the Irish people in the 4th century. The word “shamrock” derives from the Irish words seamair óg or young clover.
Clovers ( or trefoils), are plants of the genus Trifolium (from Latin tres ‘three’ and folium ‘leaf’).
There is some dispute between historians as to which variety of clover is the true shamrock.
Whether the true shamrock is Trifolium dubium (lesser/yellow clover, seamair bhuí), Trifolium repens (white clover, seamair bhán) or Trifolium pratense (red clover, seamair dhearg), we’ll leave it to the Irish historians to battle it out.
All three varieties of clover would make really lousy houseplants…hence the popularity of oxalis!
Oxalis come in numerous forms and from multiple parts of the world, but the ones promoted around St. Patrick’s Day have clover-like (trifoliate) leaves. While there are oxalis varieties native to Ireland, many of the varieties sold in home improvement stores and grocery stores around St. Patrick’s Day originate from South America or Africa.
St. Patrick’s Day Shamrock plant varieties:
- Oxalis triangularis (purple shamrock or false shamrock) — with deep purple to burgundy leaves, often with a darker center triangle pattern.
- Oxalis regnellii (green shamrock) — Native of South America with bright green leaves.
- Oxalis tetraphylla (four-leaf sorrel or iron cross) — green with a burgundy colored center
Other popular oxalis varieties:
- Oxalis adenophylla (silver shamrock) — Native to Argentina and Chile. Has light pink flowers with heavily divided leaflets. Cold hardy to zone 4.
- Oxalis vulcanicola (molten lava, copper glow) — Native of Mexico. Has brightly coloured leaves and flowers.
- Oxalis oregana (redwood sorrel) — clove like leaves with pink veined white flowers.
- Oxalis griffithii — Native of Asia. Cold hardy to zone 4. Spreads via rhizomes, not bulbs.
- Oxalis acetosella — Native to Europe. Green with white flowers. Spreads via rhizomes, not bulbs.
General characteristics:
- Leaves are trifoliate (three heart-shaped leaflets) that fold up at night or in low light (a movement called nyctinasty).
- They produce delicate, small flowers — usually white, pink, or pale purple — that bloom for long periods.
- They grow in clumps of small bulbs known as corms,
- They’re perennials and are usually grown indoors as houseplants, but can be grown outdoors in warmer climates (USDA zones 8a–11, in light shade).
Many people love them for their vibrant color (especially the purple varieties, which add contrast to green-heavy plant collections) and the way leaves “respond” to light and time of day. They are also easy to grow low-maintenance plants.
Basic care tips (as houseplants):
- Light — Bright, indirect light is ideal; some gentle morning sun works, but avoid harsh afternoon direct sun to prevent scorching.
- Water — Keep soil evenly moist but not soggy — let the top dry slightly between waterings. They don’t like their feet too wet as they will begin to rot.
- Temperature — Prefers cooler conditions (around 60–75°F / 15–24°C); hot temperatures can trigger dormancy.
- Soil — Well-draining potting mix (with perlite or sand for aeration).
- Fertilizer — Light feeding with balanced houseplant fertilizer during active growth (spring/fall); skip in dormancy.
- Dormancy — They typically go dormant for a brief period during the summer. Their leaves will die back and they may even look quite dead. Don’t despair and throw them away! Reduce watering, and possibly move them to a cooler spot out of the sun. Once they’ve rested for a month or so, they’ll surprise you and pop right back.
- Toxicity — They’re toxic if ingested in large quantities (they contain oxalic acid, like rhubarb leaves), so it’s best to keep them out of reach of pets and young children.
They’re easy to propagate by dividing the bulbs and can live for years with proper rest periods.
Overall, shamrock Oxalis plants are charming, eye-catching additions to indoor spaces — especially the purple ones that look almost like butterflies! If you’re thinking of getting one, they’re widely available as potted plants or bulbs.
Oxalis plants (like the popular shamrock or purple shamrock, Oxalis triangularis, and green shamrock, Oxalis regnellii) are among the easier houseplants to propagate. They primarily grow from small bulb-like structures called corms or tubers, which multiply naturally over time. This makes dividing them pretty straight forward.
Division of Bulbs/Corms
When to do it — Wait until the plant goes dormant (foliage fully dies back). This is usually the easiest time, as the bulbs are resting and multiply readily.
- Gently remove the entire plant from its pot.
- Shake off excess soil to expose the small, clustered bulbs (they look like tiny onions or garlic cloves, often brown and papery).
- Separate the bulbs by hand — they usually pull apart easily. If clustered tightly, use clean fingers or a small tool to tease them apart without damaging them.
- Discard any mushy, rotten, or shriveled bulbs.
- Plant the separated bulbs in fresh, well-draining potting mix (add perlite for extra drainage). Bury them about 1–2 inches deep, pointy end up if visible.
- Water lightly and place in bright, indirect light. New growth (leaves) should emerge in a few weeks to a couple of months.
Their bulbs multiply quickly (a single plant can produce many offsets in a season), so you can get several new plants from one mature clump.
