PNW Landscape Plant Guide

brought to you by the plant geeks at Calendula Farm

Oca (Oxalis tuberosa)

Oxalis plants are truly global citizens. They are native to every part of the globe where there are humans except the extreme southern and northern polar areas. Oxalis is frequently misidentified as Clover, but upon closer inspection, you’ll find that while they both have three leaves, Clover’s leaves are single ovals and Oxalis’ leaves are two-lobed heart shapes.

All Oxalis share a feature of edibility and are similar in flavor to Sorrel. In fact many of the North American species are called Wood Sorrel because of the distinctly lemon-on-lettuce flavor they have. To be clear, they are not even closely related (please see previous rants about deceptive common plant names). The leaves and stems can be added to salads for a sprightly citrusy zing and are refreshing treats for hikers in woodland areas.

The Oxalis we’re particularly excited about here is native to the central and southern Andes Mountains areas (Peru, Chile, Argentina). It grows as a soft mound of dark green heart shaped leaves about 6-12 inches tall. The branches root as they spread out to maybe 18”. It makes a lovely ground cover border plant. In early summer it offers bright yellow blooms that bees love, but late autumn is when the real action starts. Around the time when the above ground plant parts start dying back, the roots shift gears and start forming tubers. These are best harvested in December-January. Dig an inch or two down and you find many dozens of bright red or pinkish things that look like young potatoes. They’re like eating a tender jicama with lemon juice on it. Cooked, they’re like silky smooth mashed potatoes. When you harvest, you’ll never get them all, so you will always find them returning next year for more!