If anything can make a statement in your garden, it’s a delightful deluge of delphiniums!
These stately spires produce flowers in the most wonderful range of blues – a colour that’s a relative rarity in the plant world.
From deepest indigo to royal hues to the palest sky blue, there is a colour that will suit your garden’s colour theme.
Always looking for or attention, delphiniums rise above the rest of your garden bed like an exclamation mark! Growing sometimes up to 2m tall, they are towers of frilly, fluffy and decorative delight.
They welcome the warmth of a spring garden with a promise that is realised for the rest of summer as they take on the role of garden guardian, looking down like fond foster parents on the little sparklers below.
Let them take a leading role in your garden!
Fast facts about growing delphiniums
- Name: Delphinium (Delphinium elatum)
- Height: Can grow up to 2m tall, however there are dwarf varieties available that grow to around 60cm.
- Climate: Delphiniums prefer moist, cool summers. Their stems are hollow, so they fall over if it’s too windy. Even if you don’t live in a breezy area, consider staking each plant as the dozens of ruffled, trumpet-like flowers on the tall stalks can get quite heavy.
- Soil: Plant in fertile soil with good drainage. Before planting, add plenty of compost and after planting cover soil with mulch to keep in the moisture. Water regularly.
- Position: Plant in full sun and, rather than clump them together, give them plenty of breathing space.
- Feeding: Feed weekly with a high potash fertiliser.
- Watering: Give them a good watering during rainless periods, but delphiniums can be prone to crown and root rot, so don’t allow any standing water.
How to grow delphiniums
Step 1
Choose a spot in the garden that receives regular full sun (no shorter than 3 hours of direct sunlight).
Step 2
Add in a compost fertiliser or a potting mix that is high in potassium.
Step 3
Sow delphinium seeds directly into the ground. Lightly cover with soil and press down.
Step 4
Water generously.
Step 5
Cover with a newspaper, or pieces of cardboard so seeds are not overexposed to the sun. This is only until the seed is established and grows about 5cm above ground.
Step 6
Once established, feed every week or so with a high potash fertiliser.
How to prune and maintain delphiniums
Delphiniums are short-lived perennials. In their first spring, they send up spikes with several shoots.
Thin back to one or two shoots per stalk, then three or four shoots in their second year and five to eight shoots in their fourth year, when they reach their peak.
They bloom all summer long and you can keep them blooming longer by deadheading spent flower spikes back to small flowering side shoots and, when blooming has finished, cut stalks to the ground.
New, smaller flower stalks will develop that will survive light autumn frosts.
Do delphiniums spread?
Delphiniums are prone to spreading and do not like competing for space with other plants. Because of this, it is best to plant is spread out areas, and alleviate overcrowding by thinning them out.
Do delphiniums need a trellis?
Delphiniums do not usually need a trellis, however, they do grow best when supported with a stake. This is because the stem of a delphinium is actually hollow, which means it can easily fall over or break in the wind.
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