How-to Guide
Oxalis Triangularis (Purple Shamrock) Care
The short answer
First, the panic answer: an oxalis that suddenly wilts and withers after months of looking great is almost certainly entering dormancy, not dying. These are bulb plants, and Wisconsin Horticulture explains they naturally decline after several months of growth and need a rest period, after which they regrow from the bulbs as if nothing happened.
The protocol when foliage starts dying back: stop watering, let the leaves brown and dry completely, then set the pot in a cool, dark place to rest. Wisconsin Horticulture says purple-leaved types (the O. triangularis/regnelii group) need only about one month of rest, while other oxalis may rest two to three months. Then bring it back to bright light, resume watering, and new shoots follow.
In active growth, care is simple: a bright sunny window, cool rooms (ideally below 75 degrees Fahrenheit by day and noticeably cooler at night), soil kept barely moist but never wet, and monthly feeding only while it is actively growing.
Dormancy: the feature everyone mistakes for death
Oxalis grows from many small bulbs, and cycles of lush growth followed by collapse are built into the plant. Wisconsin Horticulture notes plants naturally decline after several months, often in summer, and lays out the response: stop watering when the leaves begin dying back, let the foliage brown and dry completely, and store the container in a cool, dark location to rest.
The rest is shorter than most people expect for the purple types: about one month for purple-leaved varieties per Wisconsin Horticulture, versus two to three months for others. Watering a fully dormant pot is the one real way to kill it, since bulbs sitting in wet soil with no leaves to use the water can rot; uncertainty language is fair here, but the safe default during full dormancy is no water at all.
When rest is over, move the pot back to bright light and resume watering. New shoots typically emerge within a few weeks, and the plant returns fuller than before.
Care during active growth
Light: Wisconsin Horticulture says oxalis thrive in bright light and prefer a bright sunny window; in dim light the long leaf stalks stretch and flop.
Temperature: these are cool-growers. Wisconsin Horticulture recommends keeping them below about 75 degrees Fahrenheit in the day with nights 15 to 25 degrees cooler; hot rooms are themselves a dormancy trigger.
Water and feeding: keep the soil barely moist, not wet, letting it dry slightly between waterings, and fertilize monthly only during active growth. The triangular purple leaves fold down at night and reopen in daylight; that motion is normal, and leaves that stay folded in daytime are a cue to check light and water.
Rebloom and the long game
Oxalis flower on and off through their growing cycles, with 5-petaled blooms on long stalks (white through pink and red depending on variety, per Wisconsin Horticulture) held above the foliage. Each dormancy-and-regrowth cycle resets the show: fresh foliage first, flowers following on the new flush.
The bulbs also make propagation nearly automatic. Wisconsin Horticulture notes oxalis are easy to propagate during dormancy by dividing the many small bulbs and potting them in small clusters, so one pot becomes gift plants at every rest period.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Wisconsin Horticulture (UW-Madison Extension) — Shamrocks (Oxalis) — Oxalis thrive in bright light / a bright sunny window; keep below ~75 F days with nights 15-25 degrees cooler; keep soil barely moist, not wet, tolerating slight drying; fertilize monthly only during active growth; plants naturally decline after several months (often summer) and need dormancy: stop watering as leaves die back, let foliage brown completely, store container in a cool dark place, ~2-3 months rest but only about one month for purple-leaved varieties, then resume water and bright light; 5-petaled flowers on long stalks; easy to propagate when dormant by dividing the many small bulbs