Plant and succeed with delphiniums

When to plant delphiniums?

Planting is possible in both autumn and spring. Avoid intervening during frost or extreme heat.

Some species of delphiniums are annual, so they should be sown directly in place in spring.

Where to plant them?

Plant your delphiniums in full sun! Place them sheltered from the wind, which could break the flower spikes. For example, you can position them against a wall or a hedge that will protect them from prevailing winds.

The soil must be well-drained and light! Avoid heavy, clayey soils, or work the soil to make it more permeable by incorporating gravel or coarse sand. Delphiniums do not like soils that are waterlogged in winter. However, it is important that the soil remains cool in summer. To ensure beautiful flowering, delphiniums need a very fertile and humus-rich terrain: we recommend adding compost at planting time.

Install your delphiniums preferably at the back of the border, as the taller varieties can reach up to two metres in height.

Although we recommend planting them in the ground for optimal conditions, it is also possible to plant them in pots. Choose a sufficiently deep container, and remember to add fertiliser and water regularly.

Delphiniums easily find their place in a border!

How to plant delphiniums?

• Receiving the plant:

If you order a delphinium in winter (between November and March) and receive a bucket that seems empty, this is normal: the delphinium is a deciduous plant, it loses its leaves during winter. The aerial part disappears, but the plant is still present, below the surface of the soil. It will regrow without any problem in spring.

Outside of this winter period, if you receive a young plant that has been pruned, there is no need for concern, this is normal. Pruning the delphinium helps facilitate its establishment in the garden! By cutting back the stems of the delphiniums, the plant will thicken its stump, which will ensure a more vigorous growth and better flowering.

Similarly, if the young plant is broken, you just need to cleanly cut it back with a pruning shear just below so that the plant can ramify.

• Planting:

To achieve a beautiful visual effect, we recommend planting them in groups rather than isolating them. Maintain a distance of 30 to 50 centimetres between each young plant.

1. Work the soil to loosen it with an organic fork. If your ground is heavy, it is essential to add gravel or sand to allow for drainage and prevent the soil from becoming waterlogged in winter. We also recommend adding compost to enrich the soil.
2. Dig a planting hole that is two to three times the size of the root ball. Then place a mixture of soil and compost at the bottom of the hole.
3. Position the root ball, replace the soil all around, and then firm it down.
4. Water generously.
5. Mulch to keep the soil cool.

Plan for staking as the tall stems of delphiniums are fragile and the wind could damage them. While it can be omitted for dwarf varieties, staking is essential for any variety exceeding 60 centimetres in height.

Beware of slugs and snails: they tend to eat the leaves at the beginning of the growing season when they are still tender! You can use a slug repellent to protect your young plants.

Water regularly as the delphinium does not tolerate drought, and provide some liquid fertiliser (on average every two weeks).

Check out Pascal’s article on our blog: How to ruin your Delphiniums in 4 lessons.