Hello there, fellow garden enthusiasts! It’s so lovely to connect with you today through the blog. Over my 20 years of getting my hands dirty, I’ve found immense joy in coaxing new life from established plants. And when it comes to Delphinium exaltatum, or the Tall Larkspur as it’s sometimes affectionately called, oh, the rewards are truly magnificent.
Why Grow More Tall Larkspur?
There’s something breathtaking about those spires of vibrant blue, purple, or even pink flowers reaching skyward. They add such an architectural element to any garden and are a magnet for pollinators. Propagating them means you can fill your borders with these beauties, share them with friends, or simply expand your own personal paradise. Now, I won’t lie to you – Delphiniums can be a little particular, but with a bit of patience and these tips, you’ll be well on your way. This isn’t a “stick it in dirt and forget it” kind of plant, but it’s absolutely achievable and incredibly satisfying.
When to Get Growing
For Delphinium exaltatum, my go-to time for propagation is early spring. Think March or April, when the plant is just waking up from its winter slumber. The new growth is tender and full of vigor, making it ideal for taking cuttings. You can also divide established clumps in the fall after flowering has finished and the plant is starting to wind down for winter.
Your Propagation Toolkit
Gathering your supplies beforehand makes the whole process smoother. Here’s what I always have on hand:
- Sharp Pruning Shears or a Knife: For clean cuts that heal well.
- Rooting Hormone Powder or Gel: This is my little secret for giving cuttings a boost.
- A Well-Draining Potting Mix: A blend of perlite, vermiculite, and a good quality potting soil works wonders. Some gardeners swear by a peat-free option too.
- Small Pots or Seed Trays: Clean and with drainage holes, of course.
- A Spray Bottle: For gentle misting.
- Plastic Bags or a Propagator Lid: To create a humid environment.
- Labels: Seriously, don’t skip this! You’ll thank yourself later.
Bringing New Larkspur to Life
There are a couple of very effective ways to multiply your Delphinium exaltatum.
Stem Cuttings: The Most Common Route
This is often the most successful for Delphiniums.
- Select Your Shoots: In early spring, look for non-flowering, basal shoots that are about 4–6 inches long. These are the new growths coming from the base of the plant. They should be firm but not woody.
- Make the Cut: Just below a leaf node (where a leaf attaches to the stem), make a clean cut with your sharp shears.
- Prepare the Cutting: Gently strip off the lower leaves. You want to expose the nodes from which roots will emerge.
- Dip in Rooting Hormone: Lightly coat the severed end and the lower inch or so of the stem with your rooting hormone. Tap off any excess.
- Plant the Cuttings: Fill your small pots with your prepared, moist potting mix. Make a small hole with a pencil or your finger.
- Insert and Firm: Place the cutting into the hole, ensuring the nodes are buried. Gently firm the soil around the stem to ensure good contact.
- Water and Cover: Water gently from the base to settle the soil. Then, cover the pot with a plastic bag or place it in a propagator to maintain high humidity.
Division: For Mature Plants
If you have a larger, established clump, division is a great way to rejuvenate it and get more plants.
- Dig Carefully: In the fall, after the flowering season, carefully dig around the base of the plant.
- Gently Separate: Lift the clump from the soil. You might be able to tease apart the sections with your hands. If it’s stubborn, use your sharp knife to cut through the root ball, ensuring each section has at least one or two strong buds and a good amount of root.
- Replant: Replant the divisions immediately in their new spots or in pots with fresh soil. Keep them well-watered.
The “Secret Sauce” for Success
Here are a couple of tricks I’ve learned over the years that really make a difference:
- The Bottom Heat Trick: For stem cuttings, placing your pots on a heated propagator mat can be a game-changer. This warmth encourages root development from below, while the top remains cooler, reducing the risk of rot.
- Don’t Drown Your Leaves: When misting or watering your cuttings enclosed in a bag, try to avoid the leaves touching the inside of the plastic. Condensation collecting on the leaves for too long can encourage fungal diseases. I often use small twigs to prop up the bag away from the foliage.
Aftercare and What to Watch For
Once your cuttings are potted and covered, place them in a bright, indirect light location. Avoid direct sun, which can scorch those tender new shoots. Keep the soil consistently moist but not waterlogged.
Roots typically appear within 3–6 weeks. You’ll know they’re ready to move when you see new growth emerging and feel a gentle tug when you lightly pull on the stem. At this point, you can gradually acclimatize them to lower humidity by opening the bag a little each day. Once they’re looking robust, transplant them into slightly larger pots.
What if things go wrong? The most common setback is rot. If your cuttings turn mushy and black, that’s a sign of too much moisture and not enough air circulation. Unfortunately, these are usually lost. Make sure your soil is well-draining and consider a bit more ventilation next time. If you don’t see any root development after a good while, it might just be a slower starter, or perhaps the cutting wasn’t vigorous enough to begin with. Don’t get discouraged!
Patience is a Gardener’s Virtue
Propagating Delphinium exaltatum is a journey, and like all good things in the garden, it requires a little patience. Don’t be disheartened if your first attempt isn’t a roaring success. Each plant, each cutting, is a learning experience. Enjoy the process, the quiet observation, and the sheer thrill of nurturing something new into existence. Happy gardening!
Resource:
https://identify.plantnet.org/k-world-flora/species/Delphinium%20exaltatum%20Aiton/data