Shamrocks are synonymous with St. Patrick’s Day which is celebrated on March 17th to honor the life of the patron saint of Ireland. Patrick’s real name was probably Maewyn Succat and although the day and place of his birth cannot be confirmed, some scholars place the year between 373 and 390 AD. His father was a Roman-British army officer and a deacon. Despite being a member of a church-going family, Maewyn was not a believer - until his life took an unexpected turn.
At the age of 16 he was kidnapped by pirates and sold into slavery, where he worked as a herdsman of sheep and pigs. It was during this time that he came to the conclusion that he was kidnapped and imprisoned as punishment for his lack of faith. This led him to prayer and a subsequent vision that he needed to return to Ireland to spread the news of Christianity. He escaped captivity by stowing away on a boat. After training in a monastery for twelve years, he returned to Ireland and for twenty years he travelled throughout the Emerald Isle, baptizing people and establishing schools, churches and monasteries.
What does this have to do with the Oxalis plant? Only that the trifoliate leaves of Oxalis resemble shamrocks, a symbol of the “luck of the Irish”, and this plant traditionally blooms in mid-March just in time for St. Patrick’s Day.
There are many common names for Oxalis, including Cottage Pink, False Shamrock, Love Plant, Sorrel and Wood Sorrel. It is an old fashioned perennial that has grown in gardens for centuries, but remains popular because it’s so easy to grow. All varieties are low growing (6-12” tall) and slowly spread by bulbs or rhizomes to form a rounded mound. As with most plants that grow from bulbs, the soil must be well-drained or the bulbs will rot; amending the soil with compost will not only increase drainage, but also produce a more robust plant with richer coloration and more blooms. Plant the bulbs 1” deep in prepared soil and space them 6” apart. Each bulb produces a stem and foliage; for a larger showing, place more than one bulb in the planting hole. Foliage will emerge in about six weeks and plants will begin blooming in 8-10 weeks.
Oxalis likes a partly shady spot, although varieties with purple or burgundy foliage can tolerate more sun. Hardy to zone 6, Oxalis reliably returns in North Texas (zone 8) gardens, although I have lost Purple Shamrock in extremely cold winters. Flowers are dainty, trumpet-shaped and form in clusters that grow on top of bare stems that rise above the foliage. Flower colors differ by variety and include shocking pink, white or yellow. Once in bloom, flowers will remain on the plant for several weeks. In North Texas, Oxalis blooms in the spring, takes a rest during the heat of the summer, and re-blooms again in the fall.
The most common form is Pink Wood Sorrel (Oxalis purpurea) with dainty chartreuse green rounded shamrock-shaped leaves and small, bright pink flowers with a darker pink eye. Another common form is White Shamrock (Oxalis crassipes ‘Alba’) with dark green triangular leaves and larger, white flowers. Not as readily available, but worth seeking out is Purple Shamrock (Oxalis triangularis); the dark purple triangular shaped leaves are beautiful in the garden and the white flowers create a strong contrast that pops against the foliage. The leaves of some varieties are photosensitive and will fold up on overcast days and as evening approaches.
Oxalis makes a beautiful edging plant, or plant it to form a winding ribbon through the garden. It is also easily grown in containers, providing the “filler” in the composition. The purple leaved varieties look beautiful mixed with plants with gray or silver foliage.
The common varieties are lovely in the garden, but if you like to seek out new offerings, look for these varieties offered by Proven Winners: Oxalis triangularis ‘Charmed Wine’ with purple triangular leaves and white flowers; Oxalis spiralis ‘Zinfandel’ with burgundy elongated leaves and yellow flowers; or Oxalis vulcanicola ‘Molten Lava’ with yellow-green heart-shaped leaves edged in red and yellow flowers. Note that ‘Charmed Wine’ may perform as an annual in North Texas if the winter is extreme.
Oxalis is extremely easy to grow and once you have this plant in your garden you will never be without. Don’t be surprised when your plants disappear during the heat of the summer. They go into dormancy until the cooler temperatures of fall. I have found that the Pink Wood Sorrel will remain evergreen throughout the winter, but the White and Purple Shamrocks die to the ground.
When mounds become too large for the space, carefully dig them up and using your fingers, gently tease the clusters apart too produce 2-3” bunches. Replant the divisions with some fresh compost and provide supplemental water until the plants become established. Oxalis is a perfect plant to “pass along” to a gardening friend. In fact, I received my first plants at a Master Gardener seed swap and was surprised to open the package to find not seeds but small dried bulbs. I soaked the bulbs overnight and crossed by fingers after planting them; miraculously they sprouted and bloomed the first season.
Foraging has become very popular and Oxalis has become popular as a pot herb. Some sources claim that the leaves, flowers and immature green seed pods of wood sorrel (Oxalis stricta) are all edible and have a refreshing, mild sour flavor that is said to resemble lemons. All varieties of Oxalis contain oxalic acid, which is Generally Recognized as Safe (GRAS) if consumed in small quantities (although some sources claim otherwise). Even those who endorse consuming Oxalis recommend it should be avoided if you suffer from arthritis, gout, hyperacidity, kidney stones or rheumatism. To be safe, do your research and consult a trusted source – and with plants that are foraged, it’s very important to properly identify the plant.
It is unanimous that the leaves of Oxalis can be poisonous to pets. They taste extremely sour and bitter to animals and one nibble will keep most pets away, but if you notice your pet grazing on the foliage, immediately move it to where they cannot reach it.
Oxalis is just happy as a houseplant as it is growing outdoors. Place plants in a bright eastern window in a cool room, water occasionally and feed monthly with a dilute houseplant fertilizer. Even though this is an easy care and beautiful plant, it is rather rare to find it growing as a houseplant. Maybe you will start a trend by giving in to the impulse to pick up a plant to decorate for your St. Patrick’s Day celebration. Enjoy a little “luck of the Irish” indoors and then plant it to enjoy in the garden afterwards.