Corydalis lutea, also known as Golden Bleeding Heart, Yellow Corydalis, Yellow Fumatory, and Yellow Rock Fumewort, is a short-lived perennial plant native to the southern foothills of the south-western and central Alps of Italy and Switzerland. It has been widely introduced elsewhere.
This plant grows to a height of 30-38 cm (12-15 in) and features finely divided leaves that are yellow-green to gray-green and often remain over winter. Yellow Corydalis is hardy to -34°C (-30°F), which corresponds to hardiness zone 4. It thrives in light shade conditions with good moisture, but can also tolerate full sun or deep shade. In its natural habitat, it grows in cracks in old walls with excellent drainage.
The plant produces small yellow flowers throughout the summer, creating a beautiful bluish mound of delicate foliage. It can grow in deep shade and has the ability to self-seed abundantly. Native to southern Europe, it is particularly well-suited for edging borders, filling rock gardens, cottage gardens, and woodland gardens. It also pairs well with other perennials such as bleeding heart, lady's mantle, lungwort, and foam flower in shade gardens. In sunny areas, it can be planted under taller plants like peonies or daylilies.
While yellow corydalis is known for its self-seeding properties and ability to naturalize, it can become somewhat weedy in certain conditions. However, it is easily removed if not wanted. Seedlings can be transplanted in early spring, while established plants, though not easily divided, can be moved with extra watering. Germination indoors can be challenging due to complex dormancy requirements, involving warm and cold stratifications.
Yellow Corydalis thrives in both sun and light shade and prefers well-drained soil. It does best with good moisture during hot weather but cannot tolerate wet soil in winter. It can adapt to various soil types, from ordinary to rich, humusy soil to drier, gravelly soil or sandy loam to clay.
This plant has few pests but should not be allowed to invade pastures as it is toxic to horses if ingested. For more information, visit http://plants.usda.gov.