The purple shamrock sold as a houseplant is Oxalis triangularis, also labeled false shamrock, love plant, or purple wood sorrel. NCSU lists it as previously known as Oxalis regnellii and places it in the wood sorrel family (Oxalidaceae), native to South America. It is not the Irish clover. Penn State and the University of Missouri (MU) both explain that the potted "shamrock" is usually Oxalis, while the original shamrocks are Trifolium clovers. MU adds that true shamrocks are poorly adapted to long-term life indoors.
New plants come from the underground parts. NCSU describes rhizomes with scale leaves that store water and nutrients, "like an elongated bulb," and propagates the plant by dividing the rhizome or by breaking off the scale leaves. Penn State says the same plant grows from tubers and divides it by separating some tubers into new pots. On the Arkansas Extension (UAEX) propagation table, the shamrock row marks division as the best method.
Best way indoors
| Your plant | Method | What the sources say |
|---|---|---|
| Established pot with several rhizomes or tubers | Rhizome or tuber division | Divide the rhizome (NCSU) or separate some tubers into new pots (Penn State). Division best on the UAEX table |
| Scale leaves on an unpotted rhizome | Break off the scale leaves | NCSU says broken-off scale leaves produce new plants |
| Plant has just finished a dry rest | Divide before restarting it | MU divides and repots the bulb-like structures at the end of the rest, then resumes watering |
| Fresh seed | Seed | NCSU recommends division and seed. The UAEX table marks seed no |
| A stem tip or leaf in a water jar | Not a documented method | The UAEX row marks terminal (stem tip) cuttings no, and NCSU, Penn State, and MU give no water-jar method |
General unpot-and-split steps for any clumping houseplant are on how to divide houseplants.
What you are dividing
Under the soil, the parts look different from the purple leaves above it:
- Rhizomes. NCSU describes them as unusually structured and covered in scale leaves that hold water and nutrients. UAEX, writing about the green form sold as O. regnellii, says the rhizome "looks like a zipper."
- Scale leaves. These sit on the rhizome itself. They are not the triangular leaflets on top, and a leaf-and-stalk cutting is a different thing.
- Tubers. Penn State calls the storage organs tubers. MU says many houseplant Oxalis species form tubers or bulb-like structures, while true shamrock has a fibrous root system.
Above ground, NCSU gives the plant 6 inches to 1.5 feet in height and 1 to 2 feet in width. UAEX puts the leaves on slender stalks about 6 inches long. NCSU's cultivar list includes 'Atropurpurea', with deep purple leaves edged in a wide black border and light pink summer flowers.
Materials
- A parent pot with rhizomes or tubers you can separate
- Small pots with drainage holes. Penn State notes the roots are shallow and the plants seem to prefer being pot-bound
- A loamy potting mix with good drainage (NCSU), or any good, porous potting medium (MU). For mix choices, see soil propagation
- Peat or vermiculite, only if you plan to store dormant rhizomes out of the pot (see below)
When to divide
MU says most houseplant oxalis form bulb-like storage structures and usually need a rest after their main flowering. The timing of that rest differs from one extension service to the next:
| Source | When the plant rests | What to do | How long |
|---|---|---|---|
| Penn State | Late fall, when the foliage yellows and dies | Stop watering and fertilizing. Store the pot somewhere cool and dark | One to several months, until new growth shows |
| UAEX plant-week | Late fall, when the foliage dies down | Let the pot dry down. Start watering again in early February | Until February |
| NCSU O. triangularis | Autumn, or whenever it gets too hot or too dry | Cut back on watering | Until new growth appears |
| NCSU genus page | Summer, after flowering ends (for many Oxalis species) | Reduce watering, remove dead leaves, then keep it dry in a dark, cool spot | New growth in 1 to 3 months |
| MU, for bulb-forming houseplant species | After the main flowering period, once the plant looks weak | Let it dry down, remove dead leaves, keep it dormant and dry | Four to eight weeks |
MU then divides and repots the bulb-like structures at the end of the rest, before forcing new growth, and says growth normally resumes as soon as regular watering begins. MU's rest advice covers bulb-forming houseplant oxalis in general, with O. versicolor as its example, not O. triangularis alone. MU also warns not to force a rest on a plant that keeps flowering and growing, since it probably belongs to a species with no dormancy requirement.
UAEX's general guidance agrees: divide as the plant comes out of inactive growth, usually late winter or early summer.
To store dormant rhizomes out of the pot, NCSU's genus page keeps rhizomes or bulbs in peat or vermiculite at 35 to 41 °F (2 to 5 °C).
How to divide
- Unpot the plant. Lift the root mass out at the end of its rest or as it restarts.
- Split the rhizomes or tubers. Divide the rhizome (NCSU) or separate some tubers (Penn State). UAEX's guidance for division is to tear the plant apart while keeping as much of the root system intact as possible.
- Plant the pieces. NCSU's genus page buries rhizomes or stolons about 2 inches deep. UAEX replants divisions at the same level they were growing.
- Put several in one pot if you want a full look. UAEX notes that planting several divisions in one container fills the pot faster.
- Restart the cycle. Water to restart growth (MU), and keep the new pots in a sunny window (MU).
Scale leaves
NCSU names a second vegetative method: breaking the scale leaves off the rhizome, which will produce new plants. The UAEX shamrock row also marks leaf cuttings yes without naming the part. NCSU's method uses the scale leaves on the rhizome, not the leaflets above the soil.
Seed
NCSU recommends division and seed for O. triangularis, and the NCSU genus page adds root cuttings for the genus as a whole. The UAEX table marks seed no for shamrock. NCSU, Penn State, MU, and UAEX give no germination time or sowing method for this species, so division is the reliable route when you have a parent plant.
Light, water, and feeding after potting
- Light. NCSU's species page gives full sun to partial shade, and its genus page full sun to bright indirect light. Penn State asks for bright light, UAEX for bright, indirect light, and MU for a bright, sunny window. To compare a window against a grow light, enter a light-meter reading in the propagation light DLI calculator. For a sill that gets little sun, fixture options are in best grow lights for indoor propagation.
- Temperature. Penn State says the plants prefer cool conditions, and NCSU's genus page gives 50 to 75 °F. MU says oxalis tolerates warmer homes better than clovers do.
- Water. Let the surface dry between waterings (NCSU), or let the soil dry slightly before rewatering (UAEX). Penn State warns that overwatering can lead to root rot.
- Fertilizer. Feed only while the plant is growing. Penn State uses half-strength fertilizer every two to three weeks during flowering, NCSU's genus page feeds monthly in the growing season, and UAEX fertilizes during the summer months. Penn State stops fertilizing once the plant goes dormant.
- Summer outdoors. UAEX suggests moving the plant to a shaded patio for the summer if you can.
The leaves also move. Penn State explains that many oxalis species open their leaves in bright light and close them at night or when the day is overcast. These nyctinastic, or sleep, movements come from rhythmic changes in turgor pressure in leaf cells, tied to the plant's circadian rhythm. NCSU adds that the leaves of O. triangularis close when disturbed, and its flowers also close at night. Folded leaves in the evening are normal.
Is oxalis toxic to cats and dogs?
Yes, but the risk is low. NCSU tags O. triangularis as a problem for cats, dogs, and horses, rates the poison severity as low, and names soluble calcium oxalates as the toxic principle. All parts of the plant have toxic potential, but NCSU says serious effects are usually limited to eating large quantities. It notes colic in horses and possible kidney failure if significant amounts are eaten. Penn State explains that every Oxalis contains oxalic acid, which gives the leaves their sour taste. It advises care with these plants around pets but says a pet would have to eat large amounts to be severely harmed. NCSU's genus page says to keep the plants out of reach of children and pets.
Troubleshooting
The leaves died back after dividing. Usually this is the rest, not a dead plant (see When to divide). Growth restarts once regular watering resumes after the rest (MU, UAEX).
Mushy stems and yellow leaves. NCSU's genus page links overwatering to root rot, mushy stems, and yellow leaves. Penn State also warns that overwatering can lead to root rot. Let the surface dry before watering again.
Wilting leaves. NCSU's genus page blames underwatering or low humidity. Leaves folded at night or on a dull day are the sleep movement.
Spider mites. UAEX calls spider mites the shamrock's most troublesome foe. MU says they can be quite damaging and advises regular checks for mites and other insects. NCSU's genus page also lists aphids, leaf miners, and whiteflies.
Common mistakes
- Rooting a stem tip or leaf in water. UAEX marks stem-tip cuttings no for shamrock, and NCSU, Penn State, and MU give no water method. For plants that do root in water, see water propagation.
- Forcing a dry rest on a plant that is still flowering and growing (MU).
- Fertilizing a dormant plant. Penn State stops fertilizing for the rest.
- Copying clover care onto Oxalis. The houseplant is a different genus (Penn State, MU).
People also ask
How do I divide false shamrock?
At the end of its rest, split the rhizomes or tubers and pot each piece at its old depth. NCSU also grows new plants from broken-off scale leaves.
Is indoor shamrock the same as Irish clover?
Usually not. Penn State and MU say the potted shamrock is usually Oxalis, while true shamrocks are Trifolium clovers.
Can I grow oxalis from seed?
NCSU lists seed for O. triangularis, but the UAEX propagation table marks seed no for shamrock, and no sowing method is published for it. Division is the dependable route.
Can a stem cutting root in water?
There is no documented method. UAEX marks stem-tip cuttings no for shamrock. Use division or scale leaves instead.
Is oxalis poisonous to cats and dogs?
NCSU lists it as a problem for cats, dogs, and horses with low poison severity, from soluble calcium oxalates. Penn State says a pet would have to eat large amounts to be severely harmed, but advises care around pets.
Keep reading
- How to divide houseplants: unpotting and splitting any clumping plant
- Soil propagation: potting mixes that drain
- Plant propagation: every method in one overview
- Best grow lights for indoor propagation
- Propagation light DLI calculator