While delphinium flowers present a challenge to even the most green-thumbed gardening enthusiasts; their brilliant, towering spires of richly coloured flowers make them well worth the effort to propagate. This English plant is remarkably high maintenance, but do not let that discourage you!
In this guide, we will address the finer points of delphinium flower care. Read on to find out exactly how to grow and care for delphinium plants from seed to flower.
What is a Delphinium?
Delphinium is a genus that encapsulates roughly 300 species of flowering, perennial plants that vary in colour and shape. The most common species of delphinium (also known as larkspur) is characterised by tall flower spikes that produce striking blue blossoms.
How To Grow Delphiniums From Seed
It is best to plant delphinium seeds directly into the ground, just over half a centimetre deep. Planting just before spring will lead to a summer bloom while planting in autumn will lead to a bloom in early spring.
For the seeds to germinate properly and yield the desired flowers, the soil temperature should not exceed 13 degrees Celsius. To assist in the germination process, the seeds can be chilled in the fridge for one week prior to planting. Once they are in the ground, delphinium seeds should germinate within 21 days.
When To Plant Delphinium
Due to the seed’s need for cooler temperatures, it is wisest to plant delphinium roughly two weeks before the final frost of winter. As mentioned above, planting the seeds in autumn will see the plant ready for flowering the following year.
Where To Plant Delphinium
Delphinium does best with plenty of sun exposure and consistently moist soil. Choose a spot where the sun shines for most of the day and where the soil is rich. Remember that delphinium flower spikes can grow to be as tall as a doorframe, so plant it somewhere near the back of your garden.
How To Plant Delphinium
Make sure to give the plant plenty of water during its growth phase – delphinium plants do not respond well to dry conditions. Space the seeds roughly 50cm apart to give the plants adequate room to grow. They will fill in the surrounding space once they mature. Keep the exposed ground mulched to preserve moisture within the soil and to prevent weeds from sprouting.
How To Care For Delphinium Flowers
The golden rule for preserving delphinium flowers is constant moisture. Do not ever let them dry out or they will quickly wither and die. A vital part of care for these delicate plants is regular fertilisation during the initial growth period and once the plant starts to bear flowers.
Use well broken-down organic compost or liquid flower fertiliser to encourage growth. If you see the foliage start to become yellow or stunted, increase the amount of fertiliser to provide the plant with extra nutrients.
Once the plant is in full flower, make sure to check for dead flowers. Removing the dead blossoms will prevent the formation of seed heads that will consume much of the plant’s energy. By deadheading the plant, you ensure that it will remain healthy and bloom regularly.
Do delphiniums come back every year?
Yes. Delphiniums are perennial – meaning they grow back every spring. They are tolerant of frost and will rarely be killed off during the winter months.
Do delphiniums like sun or shade?
Delphiniums much prefer sunnier spots in the garden. They typically need 6-8 hours of sun per day to flower properly. Late morning to early afternoon sun is best.
Be wary of letting the soil and roots dry out.
Are delphiniums hard to grow?
While delphiniums are not an easy plant to propagate, they thrive when given the correct care. If you heed the advice in this guide, you will undoubtedly succeed in growing them.
Is delphinium poisonous to touch?
The beauty of the delphinium flowers belies their highly toxic nature. Touching a delphinium plant can cause moderate to severe skin irritation, but it will not poison you unless you consume part of it.
How many years do delphiniums last?
With all the effort that goes into planting and caring for these perennials, one would hope they would stick around for decades. Unfortunately, delphiniums have an average lifespan of 2-3 years at most.
Do delphiniums reseed themselves?
Yes, most varieties of delphinium reseed themselves successfully from year to year.
Are delphiniums poisonous to dogs?
Yes, consumption of a delphinium plant is incredibly dangerous for dogs. Any owner that suspects their dog may have eaten delphinium should immediately take the animal to the closest vet. Untreated, the compounds in the plant can cause a myriad of unpleasant symptoms including paralysis and death.
Should I cut back delphiniums after flowering?
Yes. Cutting the stalks of the delphinium plant after it has flowered will encourage the growth of new, smaller stalks that will grow and bear flowers of their own during the following spring.
How do you keep delphiniums from falling over?
As soon as your delphinium plant approaches maturity, provide it with a stake to keep it steady. Plant the stake in the ground close to the base of the plant and loosely fasten the stem to the stake. Fully-grown delphiniums are notoriously heavy and will collapse under their own weight without much external force.
How do you get delphiniums to rebloom?
As mentioned above, if you want your delphiniums to bloom again the following year, it is vital to cut them back to allow for new growth. You can encourage the plant to regenerate faster by feeding it organic flower food and compost, providing ample mulch, and keeping the soil evenly watered. If the conditions are right, the delphinium will grow back and bloom again the following summer.
If you’re up for a bit of a challenge consider planting delphinium in your garden. They’re well worth the effort when they start blooming!