Corydalis

( koh - RID - ah - liss )

At-A-Glance Information

This genus, commonly called Fumewort or simply Corydalis, includes species of herbaceous annual, biennial, and perennial plants that are native to temperate regions of the Northern Hemisphere and high mountains in tropical eastern Africa. They grow from tuberous roots, and some species are considered to be spring ephemerals. Grow these flowering plants in woodland or shade gardens, use them to fill in spaces in mixed beds and borders, or grow them as specimens in the landscape for their sometimes curious foliage (see Corydalis cheilanthifolia). Some species can also be used in rock gardens. Take care when planting these flowers in the landscape, as ingestion of plant parts can cause toxic effects in humans and pets.

Corydalis Species and Varietals

The genus Corydalis includes around 540 distinct species and is a member of the plant family Papaveraceae. The genus name is derived from the Ancient Greek word for crested lark (korydalis), referring to the flowers' spurs. The best growing zones for Corydalis are 5-8. For more growing zone information, see the descriptions below. To find your zone, click here: Zone Map.

Corydalis ambigua
This species is native to east Asia, and grows from tuberous roots. The plant is a part of traditional Ainu cuisine, the roots often boiled and then dried for future use. Plants produce green, herbaceous foliage and flowering stems that rise above leaf clumps. Blooms are typically blue or pink, and are often bicolored. These are small plants that typically top out around 8 inches tall and 4 inches wide.

Corydalis aurea (Scrambled Eggs, Golden Smoke, Golden Corydalis)
This species is native to a wide area of North America, and can thrive in a variety of ecosystems. Flowers are golden-yellow, blooming on stems that rise above leaves. Stems are decumbent, clothed in blue-green to grey-green divided leaves. Individual plants reach up to between 6 and 24 inches tall with a spread of around two feet.
"If one word might convey the effects brought to the garden from the genus of Corydalis, I would consider 'bejeweled'."
- Dan Hinkley, Heronswood Catalog, 2003

Corydalis cava
This species reaches up to between 6 and 12 inches tall when mature and in bloom, and is native to moist, shady, woodland habitats across mainland Europe. It is considered a spring ephemeral, and produces green herbaceous foliage that dies back in summertime. Flowers appear in spring, and can range in color from mauve to purple-red  and white. 

Corydalis cheilanthifolia (Fern-Leaved Corydalis, Fern-Leaf Corydalis)
This perennial species is native to western and central areas of China. Its leaves very closely resemble those of species in the Lipfern, or Cheilanthes, genus, hence the plant's species and common names. Foliage will turn bronze and remain on the plant over the winter months. Flowers are yellow, blooming on upright racemes in spring through mid-summer.

Corydalis flavula (Yellow Fumewort, Yellow Harlequin, Fume-Root, Yellow Fumitory)
This herbaceous, perennial species is native to the eastern United States and Canada, where it typically grows in open woodland areas and on sloped landscapes. It is considered threatened with extinction in some areas of its range, and is also labeled a pioneer species, able to well-adapt to disturbed soils. Flowers are yellow, and foliage is green. Individual plants reach up to a foot tall.

Corydalis flexuosa
These plants are widely cultivated as garden ornamentals, and are native to woodland and mountainous areas of China. They reach up to 12 inches tall when mature and in-bloom, and produce blue-purple flowers. This species is summer dormant. Choice garden cultivars include 'Blue Panda' (with light blue flowers) and 'Purple Leaf' (with green-purple foliage and blue-purple flowers). Hardy to zones 5-8.

Corydalis incisa (Incised Fumewort, Purple Keman, Murasa-Kike-Man)
​This annual to biennial tuberous wildflower species is native to China, Japan, Korea, and Taiwan. It reaches up to 2 feet tall and produces herbaceous green foliage. It readily colonizes disturbed soils, reseeding freely over time. It is considered an invasive species in some areas of the East Coast of North America, forming dense stands of plants that crowd out native understory species. Flowers are pink-mauve to light purple.

Corydalis micrantha (Smallflower Fumewort, Southern Corydalis, Golden Corydalis)
Native to the southeastern United States, this annual species forms a basal rosette of green to grey-green foliage. It grows naturally in lightly wooded areas, in gravel around railroad tracks, and in disturbed soils around recently constructed buildings. Flowers are golden-yellow, and plants typically reach around 2 feet tall when mature and in bloom.

Corydalis nobilis (Siberian Corydalis)
Native to Siberia and Kazakhstan, this species produces yellow to orange flowers that form in packed inflorescences at the top of flowering stems that can reach up to 20 inches tall. The species prefers moist springtime conditions and dry summer conditions. It grows well in full sun or partial shade and is considered to be relatively hardy. 

Corydalis solida (Fumewort, Bird-In-A-Bush)
This species is native to moist, shaded landscapes in northern Europe and Asia. Individual plants reach up to 10 inches tall and produce green, divided foliage. These plants are considered to be springtime ephemerals, dying back in summer to its tuberous root. Flowers are narrow and have long spurs on them, varying in color from mauve to purple, red, and white. There are many subspecies and cultivars, including 'Beth Evans' and 'George Baker' (with bright magenta blooms).

Caring for Corydalis

Species in the Corydalis genus have a wide variety of native ranges and habitats, and therefore have varying growing requirements. Plants that are native to woodland areas will need to receive partial to full shade and have their soil kept moist, and species that inhabit sunny roadsides and more open shrubby landscapes can handle full sun and less soil moisture. Make sure you know what species of Corydalis you are growing before deciding on a planting area. Generally, the more sun a Corydalis plant gets, the more it will bloom. These plants grow from tuberous roots, and are typically purchased as bare roots, but some native nurseries also carry specimens. These plants will reseed freely, so there will be no shortage of volunteers that can be replanted elsewhere, as well. They need their soil to be well-draining, moderately fertile, and with a pH of between 5.0 and 7.0 (acidic). Water new plantings regularly as they establish a strong root system. Mulch around the base of plants to increase soil moisture retention, suppress weed growth, and keep soil temperatures from fluctuating too much.

Fertilize yearly in early springtime with a application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Prune off spent blooms after flowers have faded to clean up the appearance of plants and discourage the self-seeding tendency of these plants. Do not deadhead all flower spikes if you will be collecting seed for propagation. Corydalis plants grow from tuberous root systems, and perennial varieties will need to be divided every few years if they are being grown in a limited space, like a flower bed or a container. For instructions on how to divide Corydalis, see the Propagation section below.

Propagation

Corydalis, or Fumewort, can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Fumewort plant, follow the instructions below:

Propagating Corydalis  by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. In either late winter or early springtime, get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Corydalis by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
  1. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the tuber(s). Once you have worked it up out of the ground, lay it out.
  2. Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick tuberous root section attached.
  3. Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
  4. Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.
Corydalis seed pods form where flowers once bloomed, and will split open when ready to drop their seeds.
Corydalis seeds.

Problems and Pests

Take care when planting Corydalis in the garden, as it is known in some parts of North America as an invasive species. Check with local authorities before planting. Corydalis, or Fumewort, plants can develop issues with the following pests and diseases in the landscape:
  • Powdery Mildew
  • Slugs and Snails
  • Rust
  • Downy Mildew
  • Root Rot
For more information on these pests and diseases, including how to treat and manage them, consult the following pages:
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Gallery

Hostas and Corydalis pair well in this shady garden bed.
Rabbits are fans of the flowers, foliage, and roots of these wildflowers.
This partially shaded bed is a perfect spot for Corydalis to spread.
Here, Corydalis is planted at the base of a deciduous tree.
Corydalis flexuosa 'Purple Leaf'.
Heuchera and Corydalis are used in this shady garden bed to form a multicolored groundcover.

Videos

Learn about these small woodland plants.
Check out this volunteer Corydalis.
A great introduction to Fumewort.
How to grow and care for Corydalis plants.

Resources

Corydalis lutea (Fumewort)
What is Corydalis: Growing and Propagating Corydalis Plants
How to Plant and Grow Corydalis
Corydalis: How to Care for and Plant, Plus the Best Garden Corydalis
A Chorus of Corydalis
Wikipedia: List of Corydalis Species
Wikipedia: Corydalis 
Bleeding Hearts, Corydalis and Their Relatives, by Mark Tebbitt, Magnus Lidén, and Henrik Zetterlund. Published in association with Brooklyn Botanic Garden. (Portland: Timber Press, 2008).
Buried Treasures: Finding and Growing the World’s Choicest Bulbs, by Jānis Rukšāns. (Portland: Timber Press, 2007).
The Explorer’s Garden: Rare and Unusual Perennials, by Dan Hinkley. (Portland: Timber Press, 1999).
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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