Growing Delphiniums

How to Plant, Grow, and Care for Delphinium Flowers

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Delphiniums are perennials grown for their showy spikes of colorful summer flowers in gorgeous shades of blue, pink, white, and purple. They are popular in cottage-style gardens and cutting gardens.

Delphiniums are a favorite of many gardeners, but can sometimes be a challenge. They prefer moist, cool summers and do not fare well in hot, dry weather. The plants also dislike sudden wind or rain.

Except for the dwarf perennials, most delphiniums need staking.

Planting

Grow in fertile, well-drained soil in full sun to light shade, with shelter from strong winds.
Plant in the spring. Prepare the soil, mixing in 2 to 4 inches of compost.
Delphinium is a genus consisting of over 300 species—some are annuals, others are biennials or perennials. Some grow easily from seed, others don’t.
Dig a hole twice the diameter of the plant’s container. When planting, ensure that the top of the root ball is level with the soil.
In the spring, broadcast lime, wood ashes, or a mixture of the two over this alkaline-loving perennial. Learn more about soil amendments.

Care

Insert supports no later than midspring or when the plants reach 12 inches high. Stake the low-growing perennials with twiggy, brushwood support. The taller, large-flowered delphiniums need sturdy stakes.
Soil should not dry out. Water plants during the summer if rainfall is less than 1 inch per week.
For good-quality flower spikes, thin shoots when 3 inches high; leave a minimum of 2 or 3 shoots on young plants, and 5 to 7 shoots on well-established ones.
In growth, water all plants freely, applying a balanced liquid fertilizer every 2 to 3 weeks.
Deadhead by cutting spent flower spikes back to small, flowering side shoots.
After delphiniums have finished blooming, cut flower stalks to the ground, and new, though smaller, flower stalks will develop. The flowers will survive the coming cold days and even light frosts. (See local frost dates.)
If delphiniums need to be divided in the spring, remove and replant the new little plants growing around the outside of the clump. Discard the hard old heart.

Pests/Diseases

Susceptible to slugs and snails as well as cyclamen mites.
Powdery mildew, Southern blight, bacterial and fungal spots, gray mold, crown and root rot, white rot, rust, white smut, leaf smut, and damping off occur.

Harvest/Storage

This elegant flower is good for a cutting garden. If you take the blooms into the house as soon as they open, they will bloom again.
Add sugar plus lemon juice and bleach to arrangements of delphinium. You can also use a commercial flower preservative.

Recommended Varieties

There are dwarf-sized delphiniums and medium-sized as well as tall ones (growing up to 6 feet and higher).

Belladonna Group: Upright, loose and branching perennials with single flowers that grow 3 to 4 feet tall. ‘Blue Bees’ is a Belladonna producing clear blue flowers with white centers.
Elatum Group: These are the tallest spiked hybrids growing to 6 feet or more. ‘Blue Nile’ is a medium plant bearing semi-double, bright, and mid-blue flowers with white centers (called bees). ‘Bruce’ is a tall Elatum bearing semi-double, violet-purple flowers, paler towards the center, with brown bees.
Pacific Hybrids: Similar to Elatum Group, although not as tall, this hybrid is short-lived and often grown as annuals or biennials. ‘King Arthur’ bears plum flowers with white bees with 5- to 6-foot tall flower spikes.

Wit & Wisdom

Very young delphinium plants and delphinium seeds are poisonous. If ingested, they can cause nausea, twitching muscles, paralysis, and even death.

Reader Comments

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If your beautiful Blue has

If your beautiful Blue has flowered once this season, you may have done a perfectly good thing; it may bloom again. We can't promise but cutting back after first bloom is frequently recommended. Fertilize her once again.
BTW, how far did you cut back: what do you mean by "completely"? It is advisable to cut only the flower stalk for reblooming.

My delphiniums break off at

My delphiniums break off at the top whenever they flower. They look bad. Should I be planting them closer to the house or a similar wall for protection? Or do I need to plant them I clusters so they have each other to be more protected from the wind? They look beautiful, but grow very tall and then flower and then snap off just as soon as they are beautiful....I love the plant but feel like I'm doing something wrong....help?

This is usually an indication

This is usually an indication that the plant/s need to be staked. See here for advice and options for doing that:
http://extension.psu.edu/plant...

I am so sad! I was so

I am so sad! I was so excited to get my little Delphiniums home and planted to add a gorgeous blue to my little flowerbed. I wish I had read more on them though...I have a bazillion and one snails and they ate everything down to nubs! :( I now hate snails even more....is there a way to revive my poor Delphi-nubs?

First of all you need to get

First of all you need to get rid of your snail problem. You can buy snail and slug bait with iron phosphate, which is usually successful. Go to our slugs/snails page at http://www.almanac.com/content/slugs for more information about getting rid of snails.
If the roots are OK the delphinium will grow new leaves.

Great!! Thanks so much!

I have the same problem with

I have the same problem with slugs. Sluggo works great for getting rid of slugs and it says it works for snails also.

I just read about the green

I just read about the green looper worms and delphinium. They strip mine almost every year. Sevin ant dust works, but I know it will kill the butterflies and bees. What else could I use? They truly will destroy it in a few hours, and start with the almost-blooms most years. ps I live in Wyoming.

Hi, LuAnn, These are nasty!

Hi, LuAnn,
These are nasty! But there is not much you/we can do. We mention handpicking and Sevin below. Here's a little more:
Our bast solution is actually a few we've researched. The University of California has several suggestions: http://www.ipm.ucdavis.edu/PMG...
This Colorado State pdf has several interesting pics and offers an array of deterents and worse for loopers on page 24 (the cabbage looper appears on p 15): http://webdoc.agsci.colostate....
A third solution seems to be self inspection and removal by hand, and explained here are neem (it stops them from feeding and so eventually they die), and suggests natural enemies: http://www.extension.umn.edu/g...
If you happen on any additional or new sure-fire methods/ideas, please share!

I'm so disappointed in the

I'm so disappointed in the three Delphinium Grandiflorum "Summer Cloud". We live in Zone 9 according to another well respected site focused on Perennials only (Tampa, FL). When we purchased these at a large retailer, they were selling quickly so we snapped them up after being told it would be ok to leave in the pots as long as we kept the soil moist. About 2 weeks ago when we were finally able to plant in our flower bed all of the flowers had already fallen off. The plant instructions on this plant says "full sun", My flowerbed faces northeast and this plant gets full sun until approximately 1:00 pm (due to a bush planted approx. 2 feet behind it.
Of course because we had just planted at first the soil was kept very moist and we used a moderately priced, nutrient enriched potting soil. This time of year is known for afternoon summer rain and I'm afraid the soil hasn't had the opportunity to dry out enough for it's taste.
We've also experienced a change in color of the leaves to a light green, which was previously deep green.
We planted at least 12" apart and away from other plants in our flower bed.

It's been a while since the flowers fell off so I feel like an idiot when u refer to cutting off flower spikes. What does that mean? The whole stick? I don't know what I'm looking for & I do not want to cut the wrong piece. If it needs more prolonged sun exposure trimming the bush back isn't a problem but the actual plant is shock and although the soil has been pretty damp due to rain, it feels a little on the dry side. I'm puzzled. Can you help me to save this beautiful plant? As you can see I've tried to provide as much detail as possible. Thank you

Keep the soil moist but not

Keep the soil moist but not too wet and most delphiniums will grow well in full sun or light shade, so there is not need to trim your bush back. Cut the entire spent flower spike (stalk) back to where you see small side shoots.

Do you know where delphiniums

Do you know where delphiniums are from?

Hi, May, The modern delph is

Hi, May, The modern delph is the result of hybridization of species from around the world.
The word delphinium comes from the ancient Greeks whose word meaning dolphin (delphis) is a reference to the flower buds, suggesting that the buds resemble dophins.

I have about 20 delphinium

I have about 20 delphinium plants grown from seed in 9 inch pots in my greenhouse. Can I plant them out now oct5th or should I overwinter them in my greenhouse with a little heat and cover them with fleece to protect them from frost. Your advice would be gratefully appreciated.

We are not clear where you

We are not clear where you live. In temperature climates: If you set out your transplants in October, they will flower in late spring to early summer bloom. In areas with cold winters, you would seed in April or May. Protect from frost by loosly covering with pine branches.

I live in worsley Manchester,

I live in worsley Manchester, england

Love the Almanac, wait for it

Love the Almanac, wait for it to come out every year. I have two tall delphiniums that are about 15 years old. They always bloom late September, is there a way to speed this up?

Delphinium can be divas. A

Delphinium can be divas. A September bloom is normal for some varieties, however, if you want to improve the odds, here are tips from local cooperative extensions:
1. They like to eat a lot! Give them constant feedings with compost-enriched soil and fertilize regularly.
2. Never let them dry out. You can keep the soil evenly moist and the roots cool by mulching to a depth of 3" or 4", either with a good organic mulch or with that compost. Water well during periods of growth (in spring and after it begins its second season's growth).
3. Plant it in areas where it gets some shade during summer afternoons.
4. Over the winter, cover them with branches or mulch to protect the roots from frost heaving.
5. We aren't sure where you live, but if you get extreme colds, pick varieties that can cope well.

Hi it is the first summer

Hi it is the first summer having delphiniums in my garden in the uk, i planted late spring which maybe a little too late in the year. They did great but now in September have wilted and doubled over appearing dead. With next summer in mind do I cut back the delphiniums to just beyond the soil level and wit for summer growth next year ?? Your help would be great. Thanks

Hi, Matthew! You have not

Hi, Matthew!
You have not been waiting for a response since September, surely, have you? We check our pages frequently. Well, let's get on with it, in any case!
Our sources suggest removing the flower spike just below the lowest flower and leaving the foliage for future blooms. Smaller spikes may form near the base of the plant. Treat them the same way. Hope your dephs are dazzling!

For many years, I had

For many years, I had beautiful flowers; for about the last ten, I have an ongoing war with small green worms that eat the heart of the flower stalk before it has a chance to mature. If I sprinkle flour onto the stems, I can stop the damage up to a point; however, when it rains, the flour is gone. Does the butterfly/moth that lays the minute black eggs, do so in the fall or in the early spring? What can I do to prevent this?

This sounds like a type of

This sounds like a type of looper moth. You can do this:
Hand pick.
Control with sprays containing Sevin.
If larvae are under one inch, control with safer B.T. sprays such as Dipel or Thuricide.

Hi I have had this plant for

Hi I have had this plant for 6 yrs and it blooms beautifully and this year Calgary alberta has had aot of rain in june n july but it has been hot so far in august and now I see the leaves are brown so should I cut it down? I make sure its fertilized and not dry. should I let it keep growing as iv done for all these years or remove it

There are several reasons for

There are several reasons for brown foliage on delphiniums.
Sometimes it's overwatering.
Sometimes it's lack of nutrients; delphiniums are heavy feeders and appreciate compost and fertilizer.
Towards the end of their cycle, the foliage simply turns brown as it dies down naturally.
If you are late in the season and the brown bothers you, you can cut them down at ground level.
You don't, however, really want to cut them down if the plant is still green as this will shorten the life of the plant.

I planted 3 new delphinium

I planted 3 new delphinium plants a couple months ago. The leaves are now all brown around the edges. What is going on? Thanks for any help you can give.

Brown edges are usually a

Brown edges are usually a sign that your plant is being overwatered or underwatered. Only water perennials if the rainfall is less than 1 inch per week. Soil should never dry out.

I live in Southern Ontario,

I live in Southern Ontario, close to Toronto. I have a second-year plant that was doing wonderfully this spring. However, we've had a lot of rain the last little while and it seems to be fading fast. The leaves have turned yellow and wilted, the flowers are wilting and the stalks are doubled over as if it pain. I have hard-packed clay soil and have never had any problems with any of my other delphiniums. With all of this rain that we've had though, the area where this plant is, is boggy right now. Is my plant doomed?

Yellowing of lower leaves

Yellowing of lower leaves followed by wilting is often crown rot, but there could be other problems. Delphs do need good drainage and lots of air circulation so they're not overcrowded so a boggy area will be problematic. Take a sample your local cooperative extension for a diagnosis and action plan.

Hi, I am so new to gardening,

Hi,
I am so new to gardening, I purchased my delphinum because it was beautiful, now I am reading about acidic soil and add lime????? Can you direct me to a site that will start at the beginning and tell me how to make soil?? Sorry to interrupt, you all sound so knowledgeable, I am in Texas, it sounds like I should have never purchased this plant, it seems they hate hot weather and thats about all I get here. How do I find what zone I am in? Thank you very much for all your advice.

H, Sandra, Larkspur

H, Sandra, Larkspur (Delphinium grandiflorum) is naturalized in much of Texas. However, they are fall-seeded annuals and they complete their flowering in late spring. Then you replace with hot-season annuals, such as periwinkles, celosias, or purslanes. As you said, they do better in places with fairly moist summers versus hot weather but there are heat-tolerant varieties in Texas and perhaps you have one! Just put lots of composted manure in their bed and make sure the soil stays well-drained as delphiniums hate wet soil. Don't let the soil get too hot. Stake them as they grow tall!