Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By ROY NICOL
Roy is a Professional Gardener and Horticultural Consultant, specialising in large garden year-round maintenance and garden development. He is an RHS Master of Horticulture and uses his research in the application of no-dig methods in ornamental garden settings. Roy has been a Professional Gardener for more than six years and is a member of the Chartered Institute of Horticulture, Professional Gardener's Guild and Association of Professional Landscapers (Professional Gardener).
IN THIS GUIDE
Oxalis is a large genus of flowering plants with over 500 species from across the world that belong to the Oxalidaceae plant family.1Oxalis. (n.d.). Kew Royal Botanic Gardens. Retrieved March 21, 2023, from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30000622-2
Many of those most familiar to UK growers will be the species grown as ornamental plants outside and sometimes as potted plants indoors.
There are a huge number of oxalis varieties that you might grow here in the UK.
Here are some of the interesting options to consider.
1) O. acetosella
- COMMON NAME(S): alleluia
- HARDINESS RATING: H5
- FLOWERS: pink and white
- FLOWERING SEASON(S): spring / summer
- SUNLIGHT: part shade
Oxalis acetosella, the common wood sorrel, is a plant native to the UK.
It is a rhizomatous perennial that spreads to make a carpet of shamrock-shaped leaves and bears little funnel-shaped white flowers with fine pink veining between spring and mid-summer.
It thrives in fairly fertile, well-drained soil, rich in organic matter, in dappled shade.
“In the wild, it grows in woodlands and shaded hedgerows and is an indicator of ancient woodland, where it can be found in large swathes,” shares Master Horticulturist Roy Nicol.
2) O. adenophylla
- COMMON NAME(S): sauer klee
- HARDINESS RATING: H4
- FLOWERS: pink and purple
- FLOWERING SEASON(S): spring
- SUNLIGHT: part / full shade
Also known as sauer klee, this is a clump-forming bulbous perennial that grows to around 15cm in width and around 10cm tall.
It has greyish leaves and bears bright rosy-pink flowers with purple throats in late spring.
This oxalis variety grows well in reasonably fertile, well-drained soil in full or partial shade, and is great for a rock garden or alpine planting.
This plant holds the RHS Award of Garden Merit (AGM), meaning it performs reliably in the garden.
3) O. articulata
- COMMON NAME(S): pink sorrel
- HARDINESS RATING: H3
- FLOWERS: pink
- FLOWERING SEASON(S): summer
- SUNLIGHT: part shade / full sun
Pink sorrel is another rhizomatous perennial.
It is deciduous, forming clumps up to 45cm tall when in flower, with a spread of 0.5-1m.
It has clover-like bright green leaves on long stalks and bears its bright pink flowers on long stems through the summer months.
This type grows best in moist, well-drained soil, in sheltered conditions in full sun.
It can also be grown in a container inside an alpine house.
“In dry conditions, O. articulata will become dormant, with its leaves dying back, but it will quickly grow back in wetter conditions and is hard to kill,” shares Roy.
“It’s often grown as a houseplant or a border perennial.”
4) O. enneaphylla
- COMMON NAME(S): scurvy grass
- HARDINESS RATING: H4
- FLOWERS: pink
- FLOWERING SEASON(S): spring / summer
- SUNLIGHT: full sun
Also known as scurvy grass and holding the RHS AGM, this rhizomatous, mat-forming perennial grows around 20cm wide and up to 10cm tall.
It has slightly fleshy leaves and rosy-pink, funnel-shaped blooms, around 2.5cm in diameter, borne in late spring and early summer.
Grow this oxalis variety in reasonably fertile, well-drained conditions in full sun.
5) O. ‘Ione Hecker’
- COMMON NAME(S): wood sorrel ‘ione hecker’
- HARDINESS RATING: H4
- FLOWERS: purple
- FLOWERING SEASON(S): summer
- SUNLIGHT: full sun
This little clump-forming rhizomatous perennial grows around 8cm tall and up to around 10cm wide and holds the RHS AGM.
It has blue-grey leaves and funnel-shaped pinkish purple flowers, darker veined, around 3cm across, borne in summer.
Grow this variety in full sun in fairly fertile, moist, humus-rich soil or growing medium, or in a container in an alpine house.
6) O. massoniana
- COMMON NAME(S): masson’s wood sorrel
- HARDINESS RATING: H2
- FLOWERS: orange and yellow
- FLOWERING SEASON(S): autumn
- SUNLIGHT: full sun
A South African plant, Masson’s wood sorrel is a dwarf bulbous perennial that forms small clumps.
It has little delicate leaflets in whorls around fine stems and pale orange flowers with bright yellow eyes which are borne in autumn.
Typically grown in a container in an alpine house, this option is H2 hardy.
7) O. melanosticta ‘Ken Aslet’
- COMMON NAME(S): oxalis ‘ken aslet’
- HARDINESS RATING: H5
- FLOWERS: yellow
- FLOWERING SEASON(S): autumn
- SUNLIGHT: full sun
A small oxalis specimen that grows up to 10cm tall and 10cm wide when in flower, it has pale green, silver-haired leaves and yellow funnel-shaped flowers that appear in autumn.
Grow this option in a well-drained, sandy, low-nutrient soil or a very free-draining growing medium, in a sheltered and sunny position, or in an alpine house.
8) O. oregana
- COMMON NAME(S): redwood sorrel
- HARDINESS RATING: H5
- FLOWERS: pink, lilac and white
- FLOWERING SEASON(S): spring / summer / autumn
- SUNLIGHT: part / full shade
An interesting option for ground cover in a shady, woodland spot, the redwood sorrel is a creeping perennial with clover-like leaves and bears white, pink or lilac flowers from spring to autumn.
This is a native of western North America.
Grow in moist but well-drained fertile soil; in full or partial shade below mature trees.
9) O. tetraphylla ‘Iron Cross’
- COMMON NAME(S): oxalis ‘iron cross’
- HARDINESS RATING: H4
- FLOWERS: pink
- FLOWERING SEASON(S): spring / summer
- SUNLIGHT: full sun
This herbaceous perennial grows to around 15cm tall when in flower.
The leaves are clover-like with dark brown crosses at the base of each one that gives this plant its name.
The flowers, which emerge from late spring to late summer, are funnel-shaped and bright pink in hue.
Grow in a well-drained, nutrient-poor soil or growing medium, either outdoors in a sheltered spot or indoors in a container.
“This is a useful plant for those dry, sunny positions such as at the base of a wall where space is limited,” says Roy.
10) O. triangularis subsp. papilionacea
- COMMON NAME(S): purpleleaf false shamrock
- HARDINESS RATING: H3
- FLOWERS: pink and white
- FLOWERING SEASON(S): summer / autumn
- SUNLIGHT: part shade
Known as purpleleaf false shamrock, this is a deciduous bulbous perennial that produces purple foliage from spring through to autumn and white or pale-pink star-shaped flowers in the summer, before entering a period of winter dormancy.
You can grow this outdoors from spring to autumn and bring indoors for winter, or grow it year-round as a houseplant indoors in a bright, cool space.
11) O. tuberosa
- COMMON NAME(S): oca
- HARDINESS RATING: H2
- FLOWERS: yellow
- FLOWERING SEASON(S): summer
- SUNLIGHT: full sun / part shade
If you are looking for new, interesting edible crops to try growing in a greenhouse, oca could be an interesting option to try.
The edible tubers are a staple crop in South America and other regions.
You can grow oca in containers with a loam-based potting compost with added grit under glass in bright filtered light, with low humidity, and place plants outdoors through the summer.
12) O. versicolor
- COMMON NAME(S): striped-flowered wood sorrel
- HARDINESS RATING: H3
- FLOWERS: red and white
- FLOWERING SEASON(S): summer / autumn / winter
- SUNLIGHT: full sun / part shade
Also known as candy-striped wood sorrel, this bulbous perennial grows around 8cm tall and forms clumps of light green leaves, topped with funnel-shaped white flowers with crimson margins, which gives a striped effect when the flowers are in bud.
It blooms between late summer and winter.
Grow this variety in a humus-rich growing medium in a sheltered spot in full sun or partial shade.
Closing Thoughts
“Some species of Oxalis are a real nuisance as weeds, so I’d advise to watch out for these and remove them as soon as possible,” says Roy.
“In particular, the creeping Oxalis corniculata, an annual with small yellow flowers which develop into exploding seed pods and allow it to spread around the garden, Oxalis debilis with pink flowers which produces lots of small bulbils which are easily spread around the garden by digging, and Oxalis latifolia, again with pink flowers and which has both exploding seed pods and bulbils, making it even easier to spread around!”
There are plenty of other oxalis varieties that you might grow in your garden, under cover or indoors, but the above options are a good place to start when looking for the right oxalis for you and your garden.
