How to propagate Delphinium?

Delphinium or larkspur is a remarkable perennial that flowers from June to October, proudly bearing long floral spikes in white, pink but most often blue. This elegant, tall plant is a staple of English cottage gardens, notably the « Pacific Giant » varieties. Very floriferous and always striking in a border, delphinium performs best in full sun, sheltered from strong winds, in fertile, cool but well-drained soil. It is simple and quick to multiply by propagation by cuttings. Discover in this tutorial our tips to propagate delphinium easily.

How to take delphinium cuttings, delphinium propagation by cuttings

When to propagate delphinium?

Perennial delphinium propagation by cuttings is carried out in spring, in March or April, using young shoots. When growth starts and the plant is full of sap, taking cuttings gives very good results. Success rate is higher at this time. Propagation by cuttings should be done on plants aged 3 or 4 years, when clump reaches around twenty centimetres in height, to obtain viable cuttings.

How to multiply larkspur?

Delphinium is a short-lived perennial and multiplying it helps to perpetuate it and reproduce mother plant identically.

Using a pruning shear, take stems 8–10 cm long, cutting them as close to the stump as possible
Remove leaves from the base of the stems, keeping only one or two pairs of leaves at the tip
Halve the upper leaves to prevent cuttings from exhausting through foliage evaporation
Although facultative, you can help rooting by dipping stem bases in a rooting activator
Fill buckets with potting compost for transplanting or with a free-draining mix made of potting compost, vermiculite or sand
Firm lightly
Push shoots two-thirds into individual buckets
Firm compost around each cutting to hold it upright
Water with a sprayer. Substrate must be moist without being waterlogged.
Place cuttings under cover, i.e. under a cloche or an upturned plastic bottle or a clear plastic bag supported by stakes.
Place in light at 15 to 20°C
Water regularly
Every 3 to 4 days, lift cloche or plastic for thirty minutes to renew air; this will prevent mould
Rooting takes about four to five weeks. When roots are well developed, remove cloche
Plant out cuttings in ground at end of summer with their bucket if it is biodegradable

When to plant delphinium cuttings?

These young plants will return faithfully each year in romantic or country-style borders. They prefer heads in sun, sheltered from wind and feet in fertile, cool but well-drained soil. Remember to stake tall varieties in spring, as soon as growth begins. Water regularly during first two years after planting and in hot weather keep soil cool. A slug treatment must be applied at planting and then annually from February to protect delphinium young plants from gastropod damage.

Equipment needed to propagate delphinium:

Well-disinfected, well-sharpened pruning shear
Biodegradable buckets or plastic pots specially designed for transplanting young plants
A rooting activator (facultative)
Potting compost for cuttings
A cloche, plastic bottle or plastic bag to cover cuttings
Sprayer
Stakes