A field guide on how to identify & propagate Rock Harlequin (Corydalis sempervirens), a perennial shrub hardy up to zone 2.
Hardiness Zone: 2-9
Soil Type: Well-drained Chalk, Clay, Loam, Sand, Gravelly soil.
Water: Low to Normal.
Exposure: Full Sun to Partial Shade.
How to Identify Rock Harlequin (Corydalis sempervirens)
Rock harlequin leaves have a blue-green hue and grow in opposite arrangements on the stem.
Each spatulate-shaped leaf is divided into many lobes which have entire margins.
The upper surface of the leaves is slightly velvety, while the lower surface is smooth.
The Rock Harlequin flower is a small, tubular, delicate flower that is typically white or pale pink in color.
The extremity of the flower is a bright yellow which makes them quite appealing and eye-catching.
The Rock Harlequin (Corydalis sempervirens) flower blooming season is from May to August.
The plant typically grows in woodlands, meadows, and rocky areas.
It also likes to grow in dry woods, rocky ledges, and recent clearings.
Rock Harlequin’s natural range spreads across almost all of Canada and in some places in the Eastern United States.
Corydalis sempervirens has a high wildlife value because it is a food source for many animals, including deer, rabbits, and rodents.
The plant also provides a source of pollen for many beneficial insects.
How to Propagate Rock Harlequin (Corydalis sempervirens)
There are two good ways to propagate rock harlequin: by seed or by division.
- By seed you’ll need to order online or harvest it from the wild.
- By division you’ll need a wild plant to divide from.
Let’s see how we can do that:
How to Propagate by Seed
If you don’t have access to wild plants, you can always order seeds here at Plant World Seeds.
But if you have spotted some in the wild, here’s how to harvest them:
How to Harvest Seeds
Seeds are ready to harvest at the end of summer.
All you need to do is to collect the unripened seed heads and let them dry in a brown paper bag.
Rock harlequin seed heads look like small pea snaps.
How to Germinate
Rock harlequin seeds can germinate with cold treatment. Although your chances will greatly increase by putting the seeds in the refrigerator for a minimum of 4 weeks before attempting to sow.
For cold treatment, fill a ziplock 1/3 with sand, add the seeds and dampen. Tag the bag with the name and the date then store in the coldest area of your fridge.
Now that you gave your seeds a cold treatment, it’s time to germinate:
- Fill a seedling tray with moistened potting mix.
- Place the rock harlequin seeds on the surface of the mix.
- Moisten the soil well, and cover the pot with a clear lid or plastic wrap.
- Place the pot in a warm, well light place but away from direct sunlight.
- Check the pot daily and mist the mix with water if it begins to dry out.
- After about two weeks, the seeds should germinate and seedlings will appear.
- Once the seedlings have emerged, remove the lid or plastic wrap and place the pot in a bright location.
- Water the seedlings regularly and transplant them into individual pots when they are large enough to handle.
Seeds can take more than 6 weeks to germinate, so do not discard the seedling tray.
How to Propagate Rock Harlequin by Division
You can also propagate rock harlequin by dividing wild plants. This way you can turn one plant into many little ones.
Here’s how to do it:
- Start by finding a healthy rock harlequin plant that you want to divide.
- Carefully dig up the plant, being careful not to damage the roots.
- Gently shake off any excess soil from the roots.
- Use a sharp knife or gardening shears to divide the plant into smaller sections, making sure that each section has a good amount of roots.
- Plant the divided sections in separate pots or areas of your garden.
- Water the plants well and keep them in a shady spot until they have settled in and begun to grow.
The best time to divide is early spring when the plant is growing quickly, and before it spends energy to bloom.
If you divide off plants that are too tall, cutting them back from the top will avoid the plant from drying out too quickly.
Divided plants can take a whole season to recover but the next year they should grow vigorously.
That’s it! That should have you covered on how to identify & propagate rock harlequin (Corydalis sempervirens).
May you have great success and help populate this beautiful native plant.
Want more tips and trips on propagation? Check out our in-depth plant propagate guide.
While hiking through the forest, you might also be curious as to what mushrooms you’re seeing. In that case, check out our mushroom identification section.