Delphinium—or Larkspur, as many of us call it—is a total classic in the cottage garden. These towering beauties are famous for their stunning blue hues, and believe it or not, they can even thrive in containers if you give them a little extra love. If you’ve fallen in love with yours and want more (and who wouldn’t?), you’re in luck! You can easily propagate Delphinium through division, seeds, or cuttings.
Propagating by Division
The best time to divide your Delphinium is either in the early spring or in the fall once the blooming season has wrapped up. Simply dig up the root ball and split it into two to four sections, depending on how big it is. Just make sure every piece has at least one healthy shoot and a good set of roots attached. Pro tip: The outer parts of the rootstock are usually the most vigorous, so those are your best bet for successful division.
Growing Delphinium from Cuttings
You can also grow new Delphiniums using “basal cuttings”—these are basically young shoots that include a little piece of the root. April is the perfect time for this. If you start in the spring, you might even see your first blooms by fall! Here is the play-by-play on how to do it:
- Snip your cuttings in the spring once the plant is about 8 inches tall.
- Look for young shoots that include about a 2-inch piece of the rootstock. You really need that bit of “old wood” at the base to get the cutting to root properly.
- Prep some small pots with a 50/50 mix of sand and peat moss.
- Place the pots in a cold frame or a protected spot.
- Keep them around 60°F (15°C) for the best results.
- After about six weeks, you should see new leaves popping up—that’s your sign that roots have formed!
- Once they’re established, go ahead and transplant your new babies into the garden bed.
Growing Delphinium from Seed
If you want to go the seed route, wait until the flowers have faded in the fall and you’re done cutting them back for the season. The plant will develop seed pods (follicles). Just harvest the pods and shake the seeds out. If you keep them in a cool, dry, dark place, they’ll stay good until next spring. Just remember that these seeds often need a period of cold (stratification) before sowing.
Of course, if you’re feeling a bit lazy (we’ve all been there!), you can just leave the pods on the plant. They’ll eventually burst open on their own, and the Delphinium will happily self-seed all over your garden.
