CORYDALIS (LUTEA)

Corydalis (Lutea) (kor-ID-ah-liss LOO-tee-ah) 

Common names: Yellow fumitory, hollowort, yellow corydalis

Genus:  Corydalis  Family: Papaveraceae  Species: Pseudofumaria lutea

Type: Herbaceous perennial  Hardiness: Zone: 5 - 7  Bloom Time: May - September

Exposure: Sun - part to full shade    Height: 15" tall   Spread: 18" wide 

Description: Native range: Europe. Corydalis Lutea typically produces bright, golden-yellow flowers within a mound of ferny, medium green foliage.  The one to two inch long flowers have four petals arranged in an irregular tubular shape with a spur in the back.  Flowers are borne in racemes of six to 16 flowers on stems that rise above the foliage.  Slender, dehiscent capsules (i.e., seed pods that naturally break open along a seam) follow the flowers.  Capsules eventually burst to scatter their seed. The pinnate compound leaves have three lobes, and are pale green above and glaucous (i.e., waxy) below.  The leaves are borne on weak, hollow and fleshy stems. and resemble those of the Fernleaf Bleeding Heart (Fumariaceae family) to which it is related. Genus name comes from the Greek word korydalis meaning lark in reference to the resemblance of the plant’s floral spurs to the spurs of some larks. Specific epithet means yellowish. The genus Corydalis has approximately 300 species,

Cultivation:  Will tolerate heavy shade, but does not tolerate high humidity and high temperatures during the summer months or wet soils during winter.  Grows and spreads slowly. In mild climates, yellow corydalis remains evergreen (although not necessarily attractive), If foliage significantly depreciates in hot summers, plants may be cut back to basal leaves. In very hot summers or during drought, plants may die back, but they often resume growth in the fall when cooler, moister conditions prevail. In climates with colder winters, cordyalis can also die back to the ground. In heavier, wetter soils, shallow planting may help yellow corydalis survive harsh winters.

Fertilizer/Soil and pH/Watering: Water: Medium. Corydalis tolerates most well-drained soils but prefers rich, moist soils that do not dry out, however drainage must be good. Incorporating gravel into the soil may benefit a planting. Wet soils in winter can be fatal.

Pests/Diseases: Somewhat susceptible to downy mildew, rust, aphids, slugs, snails.

Propogation/Transplanting:   Sometimes self seeds. Seedlings that appear may be easily moved in early spring while small. Although it self-seeds readily, yellow corydalis is not easy to germinate indoors due to its complex dormancy requirements.  To germinate the seeds, sow them in a moist potting medium, then place them in a plastic bag and keep at room temperature (approximately 70ºF) for six weeks.  Move the seeds to near freezing conditions (28 to 38ºF) for six to eight weeks, then return to cool conditions (50 to 60ºF).  If there is no germination after several weeks, repeat the heating and cooling steps a second time. Established plants often do not perform well if moved.  If you do transplant yellow corydalis, plants will require extra watering and will often struggle for the remainder of the season.  Yellow corydalis plants are also not easily divided, but divisions can be made in early spring. 

Notes/Gardening Tips: Considered a classic cottage garden plant, this adaptable species is suitable for borders, rock, cottage and woodland gardens. It is a good filler and may naturalize.  Good for planting on a rock wall or slope. It can be extremely attractive when used to edge borders or walkways. It will grow well in stone walls in cool conditions.  Yellow corydalis combines well with bleeding heart (Dicentra spectabilis), lady’s mantle (Alchemilla mollis), lungwort (Pulmonaria spp.), foam flower (Tiarella spp.), hosta (Hosta spp.), leopard plant (Ligularia spp.), and many other perennials in a shade garden, or in sunny areas under taller plants like peonies (Paeonia spp.) or daylilies (Hemerocallis spp.), or as underplanting with spring-blooming blue Grape Hyacinths .

Corydalis is toxic to horses.