Greetings fellow plant enthusiasts! As a passionate gardener and nature lover, I’ve always been fascinated by the diversity of plant life that graces our planet. Recently, I found myself drawn to the enchanting world of Oxalis, a genus of plants that has captivated botanists and gardeners alike. Join me on this botanical journey as we explore the intricacies of Oxalis, from its unique characteristics to its role as both a garden and houseplant.
Unveiling the Wonders of Oxalis
Grown in the Garden and Found in Nature
The genus Oxalis, scientifically known as Oxalis spp., is a group of plants known for their distinctive leaf shapes and intriguing habits. These charming specimens can be found both in cultivated gardens and flourishing in their natural habitats. Oxalis plants are characterized by their long stems and leaves, which typically consist of three to five leaflets. These leaflets often feature notches in the middle, resembling clover leaves or even the delicate wings of butterflies.
One of the most captivating aspects of Oxalis is its daily ritual—its leaves have a fascinating habit of opening during the day and folding closed at night, almost as if they were greeting the sun each morning and bidding it farewell at nightfall. This unique behavior has earned them the endearing nickname “Shamrocks.”
The Many Faces of Oxalis
Oxalis boasts an astonishing diversity with over 550 species to its name. These versatile plants can be grown both indoors and outdoors, and whether they behave as annuals or perennials depends on the specific species and your local climate. Oxalis offers a stunning display of colors in the form of flowers, ranging from pristine white to radiant yellow, and even shades of red, pink, and purple. The foliage, too, can vary from variegated to solid green or deep purplish-red.
Some Oxalis species grow from corms, forming delightful mounds and subshrubs. Others spread through rhizomes, making them excellent ground cover options. However, it’s essential to note that Oxalis can be toxic to pets, including dogs, cats, and horses, so exercise caution when cultivating them in your garden.
A Word of Caution
While Oxalis may be a captivating addition to your garden, it’s crucial to be aware of potential invasiveness issues. Some Oxalis species, like the buttercup oxalis (Oxalis pes-caprae L.), have gained a reputation as invasive plants, particularly in regions like California. Therefore, before introducing Oxalis to your outdoor space, consult your local cooperative extension agent to ensure that the species is suitable for your region.
Getting to Know Oxalis
Before diving deeper into the world of Oxalis, let’s establish a few essential details about these enchanting plants:
- Common Names: Oxalis, Shamrock, Lucky Clover, Wood Sorrel
- Botanical Name: Oxalis
- Family: Oxalidaceae
- Plant Types: Annual, perennial, corm, or creeping rhizome
- Mature Size: 2 to 18 inches, depending on the species
- Sun Exposure: Full sun to part shade
- Soil Type: Well-drained loam
- Soil pH: 6.0 to 8.0
- Bloom Time: Summer
- Flower Colors: White, yellow, purple, pink, red, rose
- Hardiness Zones: 5 to 10 (USDA), varies by species
- Native Area: Worldwide (excluding Antarctica)
- Toxicity: Toxic to dogs, cats, and horses
Planting and Caring for Oxalis
How and When to Plant Oxalis
Oxalis thrives in regions with cool summers and mild winters. In areas with scorching summers, consider planting them in a north-facing location that receives afternoon shade. If your winters are wet, opt for raised beds or rock gardens to ensure proper drainage.
Corms can be planted in pots or trays during autumn, either for houseplant cultivation or as starters for your garden in the spring. When planting corms, position them vertically with the narrow end facing upwards. In the garden, space corms 3 to 4 inches apart and plant them 1 to 1 1/2 inches deep. For transplants, maintain a distance of 4 to 10 inches between them.
When cultivating Oxalis as houseplants, begin with shallow pots filled with well-draining indoor potting mix. Space corms 1 1/2 inches apart and maintain a shallow depth. Ensure they receive ample bright light and water them sparingly until new growth emerges. As they multiply rapidly, consider transplanting them into larger pots with proper drainage.
Oxalis Plant Care
Different Oxalis species originate from various habitats, such as woodlands, high elevations, and tropical regions. To provide the best care, aim to recreate conditions similar to their native habitats. Here are some key care considerations:
- Light: The light requirements vary among species. Tropical species suitable for USDA zones 9 to 10 can tolerate more direct sunlight, while those grown in zones 5 to 8 thrive with bright indirect light in the morning and afternoon shade to prevent excess heat.
- Soil: Plant Oxalis in well-drained, fertile soil with a slightly acidic pH. Garden-grown plants benefit from soil enriched with compost. For houseplants, consider a mix of indoor potting soil with added sand or grit.
- Water: Oxalis prefers slightly drier conditions and should not sit in soggy soil. Watering every 1 to 2 weeks, except during extended periods of heat, is typically sufficient. Most Oxalis species, both in the garden and as houseplants, enter dormancy in late summer or early autumn. During this period, withhold watering until new growth resumes in late winter or early spring.
- Temperature and Humidity: Ideal temperature and humidity levels vary by species. Tropical varieties are more heat-tolerant, while others thrive at temperatures between 60 and 75 degrees Fahrenheit. Some are frost-tender and may require winter protection, such as digging up and storing corms.
- Fertilizer: Oxalis benefits from soil enriched with compost and organic nutrients. Alternatively, use an inorganic slow-release fertilizer with an NPK ratio of 10-10-10 or 5-10-10 at the start of the growing season. Houseplants can be fertilized monthly with a diluted, all-purpose liquid houseplant food. Avoid fertilizing during dormancy.
Types of Oxalis
Oxalis offers a diverse array of species, each with its unique charm. Here are a few noteworthy Oxalis varieties:
1. Oxalis Acetosella
2. Oxalis Adenophylla
3. Oxalis Albicans
4. Oxalis Alpina
5. Oxalis Ambigua
6. Oxalis Articulata
7. Oxalis Autumn Pink
8. Oxalis Barrelieri
9. Oxalis Bifida
10. Oxalis Bowiei – Oxalis Amarantha
11. Oxalis Brasiliensis
12. Oxalis Caerulea
13. Oxalis Caprina
14. Oxalis Corniculata
15. Oxalis Debilis
16. Oxalis Dehradunensis
17. Oxalis Depressa
18. Oxalis Dillenii
19. Oxalis Enneaphylla
20. Oxalis Exilis
21. Oxalis Glabra
22. Oxalis Glauca
23. Oxalis Grandis
24. Oxalis Griffithii
25. Oxalis Hedysaroides
26. Oxalis Hirta
27. Oxalis Illinoensis
28. Oxalis Inaequalis
29. Oxalis Incarnata
30. Oxalis Lasiandra
31. Oxalis Latifolia
32. Oxalis Luederitzii
33. Oxalis Luteola
34. Oxalis Magellanica
35. Oxalis Magnifica
36. Oxalis Massoniana
37. Oxalis Melanosticta
38. Oxalis Minima
39. Oxalis Montana
40. Oxalis Obliquifolia
41. Oxalis Obtriangulata
42. Oxalis Obtusa
43. Oxalis Oregana
44. Oxalis Ortgiesii
45. Oxalis Palmifrons
46. Oxalis Pennelliana
47. Oxalis Pes-Caprae
48. Oxalis Plum Crazy
49. Oxalis Pulchella
50. Oxalis Purpurea
51. Oxalis Pusilla
52. Oxalis Regnellii
53. Oxalis Rubens
54. Oxalis Schaeferi
55. Oxalis Spiralis Vulcanicola Sunset Velvet
56. Oxalis Spiralis Vulcanicola – Oxalis Zinfandel
57. Oxalis Stricta – Oxalis Fontana
58. Oxalis Suksdorfii
59. Oxalis Tenuifolia
60. Oxalis Tetraphylla
61. Oxalis Triangularis
62. Oxalis Tuberosa
63. Oxalis Valdiviensis
64. Oxalis Versicolor
65. Oxalis Violacea
66. Oxalis Virginea
Pruning and Propagating Oxalis
To keep your Oxalis thriving, consider these essential pruning and propagation tips:
- Pruning: After flowering or when not flowering, many Oxalis species enter a period of dormancy in late summer or early autumn. During this time, remove brown, dead foliage and deadhead spent flowers by cutting the entire stem at the base.
- Propagating: Oxalis corms multiply rapidly, making division a straightforward process when new growth emerges in early spring. Follow these steps for propagation:
- Use a garden spade, fork, or shovel, along with a sterile cutting tool.
- Dig around the outside of a clump of Oxalis, reaching down 8 to 10 inches to remove corms and roots.
- Lift out the clump and remove as much soil as possible.
- Corms can easily pull apart or be cut to separate them. Each piece should include roots and the beginning of a green shoot.
- Plant the divided corms just below the soil level in a new location, ensuring thorough watering and allowing the soil to dry between subsequent waterings.
Potting and Repotting Oxalis
When transplanting an individual seedling into a pot, use a deep container with a 5-inch diameter, filled with a mixture of potting soil and sand or grit. Position the seedling in the middle of the pot with the crown slightly above the soil level and water thoroughly.
Potted Oxalis should be divided annually or moved into a container that is 2 inches larger in diameter. When repotting, gently remove the plant from its original pot, add and tamp down soil, and water thoroughly.
In regions with colder temperatures, outdoor Oxalis grown in pots can be brought indoors when nighttime temperatures drop below 50 degrees Fahrenheit. Keep the potted plants in an unheated basement or garage, allowing them to go dormant. Remove any leaves that have withered and ceased growth, withholding water and fertilizer.
For garden-grown plants perennial to your specific growing zone, prune them back to ground level in autumn. If you’re cultivating perennial species outside their hardiness zone, consider digging up the corms in autumn. Store them in a container with moistened sphagnum moss, keeping them in a cool, dark location until they can be replanted the following spring.
Houseplants require a rest period lasting one to three months. After the foliage has died back, place the pot in a cool, dark room, refraining from watering and fertilizing. Once the dormancy period ends, return the Oxalis plant to a spot with bright, indirect light and resume regular care.
Common Pests and Plant Diseases
While generally hardy, Oxalis can occasionally attract pests and experience fungal infections. Here are some common issues and their solutions:
- Pests: Oxalis may attract spider mites and leafminers, which can affect the appearance of the foliage. Use neem oil as a preventive measure or apply a pesticide specifically formulated for leafminers in severe cases.
- Fungal Infections: Oxalis can be susceptible to fungal infections such as mildew, leaf spots, and rust. These can be treated with appropriate fungicides.
Encouraging Oxalis to Bloom
To witness the exquisite blooms of Oxalis, it’s essential to understand their need for a period of dormancy. Whether grown indoors or outdoors, once the foliage begins to wither and enter dormancy, refrain from watering and fertilizing. Only when the plant renews growth in late winter or early spring should you resume normal care.
Additionally, planting an Oxalis species native to your specific growing zone increases the likelihood of abundant flowering. While Oxalis adapts to various soil types, it can be particular about sun exposure, heat levels, and moisture.
Exploring Oxalis Flowers
Oxalis blooms are a sight to behold, characterized by five ray-type petals per flower. The colors span a wide spectrum, including white, yellow, orange, red, purples, and pinks. Many Oxalis species feature contrasting colors in the center or narrow veins throughout the petals. Some varieties also boast a delightful fragrance, adding to their allure.
Common Challenges with Oxalis
When growing Oxalis, you may encounter a few common challenges, often related to environmental conditions or maintenance errors:
- Failure to Bloom: Achieving blooming success with Oxalis hinges on allowing the plant to experience a period of dormancy. The chances of abundant flowering improve when you choose species adapted to your specific growing zone.
- Leggy Appearance: If your Oxalis appears leggy and stretched out, consider relocating it to a spot with better light conditions or removing nearby foliage that might be casting shade over it.
Frequently Asked Questions
Let’s address some common questions about Oxalis:
- Why have my Oxalis plants fallen over? Several factors can cause Oxalis to droop. It may be overwatered, so allow the soil to dry out by about 75% between waterings. If it’s not receiving enough light, the stems may become leggy and topple as they reach for better light. Lastly, the plant could be entering dormancy.
- Is Oxalis invasive? While some Oxalis species are considered invasive, especially those that spread through underground rhizomes, ornamental bulb and corm species are typically not invasive.
- Can you keep Oxalis as a houseplant? Many Oxalis species that originate from corms can indeed be grown as houseplants, provided they receive the right conditions.
Exploring the world of Oxalis has been a captivating journey filled with vibrant colors, intriguing habits, and valuable care insights. These versatile plants can add a touch of enchantment to your garden or brighten up your indoor spaces. Remember to tailor your care routine to the specific Oxalis species you choose, and always consider your local climate and conditions.
As I conclude this botanical adventure, I hope you’ve gained a newfound appreciation for the genus Oxalis and are inspired to welcome these remarkable plants into your own gardening world. Whether you’re cultivating them for their charming blooms, distinctive foliage, or their unique daily ritual of leaf movement, Oxalis is a treasure trove of natural wonders waiting to be discovered in your garden or home.