Plant of the Month - June 2022
GENERAL INFORMATION: The Oxalidaceae or wood sorrel family has five genera. Oxalis is the largest genus with over 550 herbaceous species. The other four genera have 15 species, some of which are woody.
Oxalis distribution is world wide with many species in tropical South America, Brazil and Mexico. The wood sorrel group has an acid taste and are mostly annual or perennial. Oxalis stricta, O. dillenii, O. corniculata, are similar looking weeds in our southern Ontario gardens.
Oxalis laciniata Estancia Stag River Oxalis adenophylla Cerro Chapelco
There are several desirable Oxalis species in South Africa and Patagonia. I saw several lovely forms of rosy purple Oxalis enneaphylla and purplish O. laciniata growing up to 1100 m in cold, wind swept grassland at Estancia Stag River in Southern Patagonia. There are several forms in cultivation.
Oxalis erythrorhiza grows in the Andes above the tree line to 4000 m, forming hard mounds with yellow flowers.
Oxalis adenophylla grows around the tree line in more or less level open screes.
Common Name: Silver Shamrock, Pink Buttercups.
Oxalis adenophylla in our garden
Cultivars: Oxalis adenophylla ‘Purple Heart’ has leaflets with a purplish base, O. a. ‘Brenda Anderson’, O.a. ‘Tora’ and other white and purple forms are all difficult to find.
Life Cycle: Stemless, perennial, whiskery corm.
Height: to 10 cm, spreading to 30 cm.
Bloom Time: May to early June in Toronto.
Flower Colour & Size: Open funnel-shaped, 2-5 cm long. 5 pink petals fading to white at the base. They have darker pink veins and a purple marked throat. Petals are twisted in bud.
Oxalis adenophylla flowers and leaves
Leaves: Clover like. Compound silver green heart shaped leaflets, in clusters of 9 to 20. Closed at night.
Range: Argentinian & Chilean Andes.
Habitat: Screes, flat open areas, near or above the tree line.
Plant: To 7.5 cm deep, with fibrous roots down.
Light: Full sun to semi shade.
Soil: Rock Garden: Well drained and fairly fertile. Most types of soil.
Water: Moderate amounts when in full growth.
USDA Hardiness: Zone 4-9.
Companion planting: Other short rock garden plants.
Propagation: Divide corms and replant in the fall. Rarely sets seeds. If it does - small capsule with several seeds.
Problems: Corms rot with winter wet. Survives freezing.
Encyclopedia of Alpines; AGS Publications 1994
Text and images supplied by Anna Leggatt