What Is Delphinium?

Learning about the flowers that grow, or might grow, in your garden and neighborhood is an important way to understand your environment. This is especially true if you have any interest in gardening yourself and want to begin planting flowers this year.

One of the loveliest varieties of flowers you may consider for your garden includes delphinium, a flower prizes for its rare true-blue shades that may be paired with a number of its other colors.

There are many things you should know about delphinium before you should consider growing it. They’re beautiful, yes, and have a variety of giant flowers whose stalks reach eight feet in height, but there’s so much more to these plants than mere looks.

What Is Delphinium?

What is Delphinium?

Delphinium is a perennial flower type that flourishes in the summer time with brilliant displays of gorgeous shades of pink, true blue, white, yellow, red, or purple. They’re particularly popular in cottage style gardens and cutting gardens.

Delphinium has some other names that you may also know it by, including larkspur, knight’s spur, lark’s claw, or lark’s heel.

The unique and rare shades of true blue of delphinium is one of the main reasons these lovely flowers are so highly sought after. Their deep, pleasing green foliage that comes in palm-shaped leaves that look like ferns doesn’t hurt their cause.

They’re a well-loved flower, but they can be a difficult plant to successfully grow.

Delphinium prefers moist, cool summers, and don’t do well in hot, dry places. They also like sudden wind and rain, and they require staking. The dwarf varieties, however, are okay without staking.

How Do You Plant Delphinium?

How Do You Plant Delphinium?

There are a number of things you need to keep in mind as you plant and grow these beautiful flowers.

1. Soil Type

Delphiniums need deep, fertile, and well-drained soil in full sun to light shade. They also need to be sheltered from high winds.

Ultimately, these flowers need about eight hours of sunlight per day.

Do not plant them in spots where water can stand after rainfall.

Add at least three inches of compost to the soil before planting, and one inch of well-rotted manure. Add one pound of powdered, all-purpose fertilizer per every twenty-five feet of garden bed, and be sure to turn the soil to incorporate the fertilizer properly.

2. Planting Time

Delphinium need to be planted in the springtime. You’ll need to properly prepare the soil first, mixing in about two to four inches of compost. This ensure the plant will receive the nutrients it will need to grow properly and flourish when summer arrives.

3. Varieties To Choose From

Delphinium have over 300 species. Some of these are perennials, some are annuals, and some are biennials.

Some of these varieties of delphinium grow easily from seeds, while others don’t. Before you decide on any particular variety, be sure to study up on what stage you should bring them home, whether seed, seedling, or full-fledged plant.

4. Hole Preparation And Plant Placement

Plant the delphinium plants about twenty to twenty-four inches apart, setting them in small, individual holes.

As you dig the hole, make sure you make it twice the diameter of the plant’s container. Then, after you’ve placed the plant into the soil, make sure that the top of the root ball ends level with the soil. Gently firm the soil around the roots to ensure the plants remain in place as they take root.

5. Broadcasting

During the spring, you’ll need to broadcast wood ashes, lime, or a mixture of the two, over this plant that loves alkaline.

6. Placement

You’ll want to plant these flowers at the back border of your garden, since the larger varieties often grow to what can be safely considered giant heights.

If you’re planting the dwarf varieties instead, you may choose to mingle the plants among your others but remember that even the dwarves tend to be taller than a number of other plants.

How To Care For Delphinium

How to Care for Delphinium

Interestingly enough, delphinium are perennials, but many gardeners grow them as annuals. They’ll grow for several years, blooming happily, before you’ll need to dig them up and divide them.

To ensure they remain healthy and happy plants, you’ll want to take proper care of them.

Here are a few tips and thoughts on how to best care for your delphinium plants.

Things You’ll Need To Care For Your Delphiniums

  • Compost
  • Manure
  • Powdered all-purpose fertilizer
  • Rake
  • Watering can
  • Shovel
  • Soaker hose
  • Mulch

Things You’ll Need To Do for Your Delphiniums


As your garden blooms and grows, you’ll need to hand water each individual plant with a watering can. Do this at least twice a week until new growth appears.

After that, water the plants at soil level with soaker hose laid on the surface.

Do not water with an overhead sprinkler, as excess water can damage the flowers and cause issues like powdery mildew.


To control the weeds around your delphinium, you’ll want to mulch. Be careful not to use a garden claw around the base of the plants, though. Delphinium plants are shallow rooted, and that kind of cultivation can damage the roots of your desirable plants.

You should apply a four-inch thick layer of buckwheat hulls, hay, or straw the mulch the bed properly.


Once your delphinium plants reach about twenty-four inches in height, you’ll need to stake them. Bamboo stakes are recommended.

Make the stakes at least as tall as the expected height of the plant variety.


Delphiniums need to be fed monthly with powdered, all-purpose fertilizer. Lift back the mulch from the plants and apply two or three tablespoons of the fertilizer at the base of every delphinium plant.

Do not scratch the fertilizer into the soil, but just replace the mulch and water with a watering can as usual.


Be sure to cut the flower stalk just below the lowest flower when the bloom fades.

And make sure you cut down the faded foliage after frost kills it in autumn. Mulch the roots with at least half a foot of hay or fallen leaves for the winter, and re-mulch in early spring about a week before your normal spring frost.

Recommended Varieties To Plant In Your Garden

There are a wide variety of types of delphinium flowers to choose from, ranging from dwarf varieties and medium varieties to varieties that grow rather tall at sometimes as tall as a giant eight feet.

There are particular groups of delphinium plants that come recommended for your cottage or cutting garden.

Delphinium Belladonna Oriental Blue Perennial Seeds

The Belladonna group delphinium are an upright, branching, and loose perennial with single flowers. This variety may grow to three or four feet tall.

One popular type among the Belladonna group is the “Blue Bees,” which produces clear blue flowers that have white centers.

30 Seeds of Perennial Delphinium elatum - Guardian Dark Blue. Regal...

The Elatum group is the tallest spiked hybrid group, which may grow up to as tall as six feet, or possibly taller if well-cared for.

“Blue Nile” is one plant that bears semi-double, mid-blue, bright flowers with white centers. These white centers, by the way, are called bees.

“Bruce” is another Elatum group flower. The Bruce is a taller flower that bears semi-double, violet-purple flowers that are paler towards the center. These flowers have brown bees.

Delphinium Pacific Giant Series Flower Seeds - Round Table Mix - 1000...

The third most recommended group of delphiniums are the Pacific hybrids. These are not as tall as Elatum and are short-lived. They often are annuals or biennials.

The “King Arthur” plant bears plum colored flowers with white bees and tend to have five to six food tall flower spikes.

Comparison Table

Pests And Issues Delphinium Have

Delphinium plants are quite susceptible to slugs, snails, and cyclamen mites.

They may also have issues with powdery mildew, bacterial spots, gray mold, fungal spots, crown rot, white rot, root rot, southern blight, white smut, rust, leaf smut, or damping off.

Harvesting And Storage Of Delphinium

This beautiful and elegant flower is often found in cutting gardens. That means if you get the blooms straight to the house as soon as they bloom, they will bloom again.

To keep the flowers fresh once cut, add sugar, bleach, and lemon juice to the water. Commercial flower preservative will also work.

Safety Precautions

It’s important to note that both the seeds and every part of the delphinium plant itself are poisonous. If either is ingested, you may experience twitching muscles, paralysis, nausea, and even death. Rush immediately to poison control if this plant or seeds have been ingested.

Care For And Enjoy Your Delphinium

As you consider planting delphiniums, or larkspur, in your cottage or cutting garden, be sure to consider the type of care these plants need. Plan out the placement of them carefully to ensure both enough sunlight, and to avoid these large plants overshadowing your other ornamental plants.

Water properly, mulch, and fertilize as recommended, and you’re likely to enjoy these flowers for years before you’ll need to dig them up and divide them into more plants.

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