Nothing quite beats the drama of delphinium flowers. In June and July, they produce towering flower spikes that can reach over 2m tall. They have flowers that are more than just sapphire blue. You can get them in mauve, pink, white, and even red. Delphinum flowers can be single or double, depending on the variety.
You can find delphiniums in herbaceous borders and cottage gardens. They add height and color to displays and go well with roses, peonies, and other vertical flowers like verbascum and lupins. The flowers are loved by bees and look stunning in a vase.
Delphiniums are in the buttercup family (Ranunculaceae) and have been grown in the UK for centuries. The word “delphinium” comes from the Greek word “delphinos,” which means “dolphin.” This is likely because of the way the flowers open. Their common name, larkspur, dates back to Tudor times.
Most delphiniums are hardy perennials, but annual and biennial varieties are also available. The Elatum Group of delphiniums is the most common and tallest type. They can grow up to 2 m tall and have spikes of single or double flowers. Belladonna delphiniums are shorter, with a looser, more branching habit and single flowers. ‘Pacific Hybrids’ were developed in the 1950s and 1960s, and are short-lived perennials or biennials. They look similar to ‘Elatum’ delphiniums but are shorter. The ‘Magic Fountain’ series of delphiniums are short and more compact, suitable for smaller gardens.
Delphiniums need care to keep them looking good. They need protecting from slugs in spring, staking, moist soil and plenty of feeding. And if you cut them down to the ground after they flower, you might get more flowers in September.
With their tall, vivid flower spikes, delphiniums bring drama to gardens in early summer. While you can purchase young plants, growing delphiniums from seeds is often more affordable. Here is a complete guide to successfully germinating delphinium seeds and raising the seedlings into mature, flowering plants.
Why Grow Delphiniums from Seeds?
Starting delphiniums from seeds has advantages including
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Lower cost – Packets of seeds are much less expensive than buying starter plants.
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Wider variety – Many more seed varieties exist compared to plants offered at nurseries
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Custom colors – Mix your own colors by growing an array of seed varieties together.
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Seed saving – Mature delphiniums produce abundant seed pods for collecting seeds.
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Satisfaction – It’s rewarding to grow these stately plants from tiny seeds.
Overall, growing delphiniums from seeds gives you more options and allows these stunning plants to be enjoyed in your garden on a budget.
Timing for Sowing Delphinium Seeds
Delphinium seeds require cool soil temperatures for best germination. Sow seeds:
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Early spring indoors – Start 6-8 weeks before your last frost date.
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Late summer/early fall – Sow in late summer to early fall for germination the following spring.
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Outdoors after frost – Sow directly in the garden after all chance of frost has passed.
Timing your sowing properly sets your young seedlings up for success.
How to Sow Delphinium Seeds
Follow these steps for sowing delphinium seeds:
Indoors
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Fill seed trays or pots with seed starting mix. Moisten the mix well before planting.
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Sow seeds 1/8 inch deep and 4 inches apart to allow room for growth.
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Cover trays with plastic wrap or place in a propagator to retain moisture.
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Keep at 60-70°F until germination in 10-20 days. Move to a sunny window once sprouted.
Outdoors
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Prepare a seedbed in full sun with compost-enriched soil. Rake smooth.
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Sow seeds 1/8 inch deep and 4 inches apart in rows or clusters.
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Gently water seeds daily to keep moist, not soaked.
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Thin seedlings to 10-12 inches apart once they sprout.
Caring for Young Delphinium Seedlings
Keep your sprouting delphiniums thriving with:
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Bright indirect sunlight or dappled shade to prevent scorching.
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Consistent moisture – avoid both dryness and waterlogging.
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Good air circulation to prevent fungal issues like powdery mildew.
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Liquid fertilizer every 2-3 weeks to fuel rapid growth. Use formulas for seedlings.
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Slug and snail control like organic baits or copper tape – they devour seedlings!
Proper seedling care results in stocky, vigorous young delphinium plants ready to transplant.
When and How to Transplant Delphinium Seedlings
Move delphinium seedlings into the garden after hardening off when they have 4-6 true leaves.
Hardening Off
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Start 1-2 weeks before transplanting.
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Move plants outside to a sheltered, shaded spot for a few hours daily.
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Slowly increase outdoor time over the hardening off period.
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Bring seedlings back indoors at night until transplanting.
Transplanting
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Prepare growing sites in full sun with compost-enriched soil.
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Space plants 10-12 inches apart in rows or groups.
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Dig holes the width of the root ball and slightly deeper.
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Carefully separate and transplant seedlings, keeping the root ball intact.
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Backfill holes and gently firm soil. Water thoroughly.
Ongoing Care of Delphinium Plants
Once settled into the garden, delphiniums need:
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1-2 inches of water weekly from rain or irrigation, more in heat.
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Staking of taller varieties as they grow using bamboo canes or metal stakes.
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Deadheading spent blooms to encourage reblooming.
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Cutting back flower stems to the base after spring flowering is finished.
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Division of overcrowded plants every 2-3 years in early spring.
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Mulching in fall with compost or shredded leaves.
With proper care, delphinium seedlings will grow into multi-year flowering garden specimens. Starting them yourself from seeds is deeply satisfying!
Troubleshooting Common Delphinium Growing Problems
Here are some potential issues and solutions for delphiniums grown from seed:
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Poor or spotty germination – Ensure seeds are planted at the correct depth and soils stay moist. Cover seeded trays to retain moisture.
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Seedlings dying – Protect from slugs and snails. Avoid overwatering or fungal issues.
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Spindly, weak growth – Give more light and use a fan for airflow. Fertilize regularly.
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Leaf spot or powdery mildew – Improve air circulation. Water at soil level rather than on leaves.
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Failure to flower – Some seed varieties are biennial and won’t bloom until second year. Be patient!
Catch problems early and adjust care methods to get your homegrown delphiniums thriving. With proper germination and seedling care, growing these gorgeous plants from seeds is very rewarding!
How to propagate delphiniums
You can grow delphiniums from seed. Many varieties are available, or you can try saving your own. Sow delphinium seeds from February to June, or in September or October. Sow in small pots or seed trays and keep at a temperature of around 50°-60°F.
To make more delphiniums, take cuttings from the base of the plant in the spring. These are called “basal cuttings.”
To take basal cuttings from a delphinium:
- When the new shoots show up in the spring, cut one just below the ground with a sharp knife. Take one or two shoots from each plant.
- Right away, put the cut piece in a polythene bag to keep the moisture in.
- Leave a few leaves on top of the cutting after cutting off some. This will help the roots grow.
- Put each cutting in a small pot that is full of different kinds of compost and perlite.
- To keep the water in, water the plants and cover them with a polythene bag. You can also mist them often to keep them from drying out.
- Keep in the greenhouse or on a sunny windowsill
Here, Monty Don shows how to take basal cuttings from delphiniums: Green Video Post Element Video ID: “9d83e1da0b94035bfcebba5dd83d65086e73e137” Mix ID: “” Player ID: “qAUyOzk5” If the player doesn’t show up in a few seconds, the Player ID or License Key (set in IM Green Video settings) might not work.
Here, Monty shows how to pot up rooted delphinium cuttings: Green Video Post Element Video ID: “fb4635611459219a2340116274bcc1df7e3708c9” Mix ID: “” Player ID: “qAUyOzk5” If the player doesn’t show up in a few seconds, the Player ID or License Key (set in IM Green Video settings) might not work.
How to plant delphiniums
No matter what time of year you plant it, spring or fall is best because the soil is warm and moist. Dig a planting hole and add compost or well-rotted manure in the bottom, for a nutritious boost. Delphiniums struggle in winter wet, so add grit to heavy soils to aid drainage. Put your delphinium in the ground at the same depth it was at in the pot, and gently press the soil back into place. Water in well.
How to Grow Delphinium Flowers From Seed – From Planting Seed to Flowering Delphinium Plant
FAQ
Are delphiniums hard to grow from seed?
How long does it take for delphinium seeds to germinate?
Do delphinium seeds need darkness to germinate?
How do you plant Delphinium seeds?
Put the seeds on a wet coffee filter and fold in half so that the seeds are inside. Place this in an out of the way place but not necessarily in the dark. In about a week you should see little roots emerging. Whether you’re sowing delphinium indoors or out, cover the seeds with about an eighth of an inch (one-third cm.) of soil.
When should I plant Delphinium seeds?
Delphinium seeds should be planted indoors about **eight weeks before the last frost of spring** or directly in flower beds in early summer.If sowing outside, you may want to let the seeds germinate first.
Can delphiniums grow from seed?
From my experience, delphiniums can be quite tricky to grow from seed. Delphiniums are perennials. As with most perennials, they have improved germination with a process called stratification.
How long does Delphinium take to grow?
Keep the soil moist and at a temperature of about 70 to 75 degrees F. (21-24 C.). Delphinium seed planting should lead to seedlings in about three weeks. Make sure they get plenty of light at this point if indoors. The seedlings should have two or more pairs of true leaves before they are transplanted outdoors.