Why You Should Grow Delphinium

Grow delphiniums for the summer-blooming garden, and the tall flower spires provide a focal point of interest in any garden setting.

Gardening Tips On How To Grow Delphiniums

Delphinium is one of the early summer blooming perennials that’s worth growing. Delphinium will grow back every year without much special care needed.

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Every year I look forward to the early summer when the garden is starting to bloom. Delphinium is a showstopper in the garden. Almost every corner of my garden has these majestic flowers blooming.

It is somewhat hard to find blue flowers. There only specific flower varieties I can see in the garden center like delphinium, catmint, hydrangea. I have to grow it from seed if I want to plant different types of blue flowers.

Are Delphiniums Hard To Grow

Growing delphinium is not that difficult, but also it is not easy, like growing marigold. With special care but on the minimal side, you can have delphinium blooming year after year.

Just like any other plant, delphinium needs some basic care to keep the plant healthy. With proper growing medium and planting site, delphinium will reward you with blooming spikes and towering stalk that perfect addition for cut flowers.

Where To Plant Delphinium

Grow delphinium in the full sun for the best result. I also have success growing the flower in the partial shade that got at least the first 6 hours of full sun throughout the day.

If you grow the tall variety, you will need protection from the wind as the stalk tend to bend. I grow this variety against the wall on partial shade area, and between tall shrub to help support the flower stalk.

The tall one like Pacific Giant variety can grow up to 1.2-1.8 m (4-6′), and it is an excellent plant for the back of the border. Mine can grow up to 2 m tall (6.5′).

The dwarf variety grows just fine in the full sun and stand still even though we have windy summer once a while.

Where To Buy Delphinium

Any garden center and grocery store carry the seed by late winter. You will also find seedlings at the plant nurseries. These are mostly the second year seedling. So you will get the flower in the same year you grow it from the seedling.

If you grow delphinium from seed, you will get the flower in the second year as most perennial do. It might start with a small flower spike, but you will get much taller ones, and the plant doubles its size the following year after year.

Here is the link to get delphinium seeds. This one is the Pacific Giant Delphinium Variety, and this one is the Dwarf Delphinium Variety.

How To Propagate Delphinium?

Delphinium is one of the perennial flowers that easy to grow from seed, which is a great way to keep gardening on a budget. From a package of seeds, you will get multiple plants that will come back year after year.

How To Grow Delphinium From Seed

If you are starting delphinium from seed, you can do it indoor and direct sow in the garden. For indoor seeding, sow the seed about 8-10 weeks before the last spring frost in your area.

Cover the seed lightly and provide cool temperatures. Germination will take up to 3 weeks. Here are things you need to help you with indoor seeding.

Once the seedling has three true leaves, then thin them out or transplant it into an individual container. Once the last spring frost pass, you can gradually harden them off by introducing the plants to the real outdoor condition for up to two weeks.

The easy way to grow delphinium from seed is by direct sow outdoors. I usually do it in around late spring or late summer.

When you direct sow the seed in the early spring, the plant might look small during the growing season. But it will bounce back and grow double the size the next following year.

If you sow the seed by early falls, it will give them cold stratification naturally. The seedling will emerge in the spring and bloom in the next following year.

How To Divide Delphinium Plant

Another easy way to grow delphinium is by dividing the root ball. I have success by doing this in the early spring, once it shows the sign of the first shoot.

Make sure you don’t disturb the root too much by carefully digging the whole root ball and separate the plant base. You can have multiple mature plants this way.

I also often move the plant throughout the garden this way. If there is plenty of organic matter on the new planting site, the plant will grow nicely and give you beautiful flower spires.

How To Care Delphinium

Like most flowers, you need to prepare the growing space by adding organic matter into the ground. If you have a hard compacted garden with clay, add compost or well-composted manure.

Water the plant regularly, I do it in the early morning so the ground can dry up before night time. Make sure the growing site has well-draining soil.

The tall spiky flowers some time give too much weight for plant stalk to stand still. It often bends over, or flop, then broke the stem altogether. It happens a lot, especially when there is a wind storm and continues with heavy rain.

You can help the plant by staking them for support by using a bamboo stick or these metal plastic coated plant stakes. I also support delphinium by using the tallest tomato cage I can find.

If you grow delphinium against the wall or fence as I do, you can use the plant trellis, then secure the plant stalk with garden twine.

Should Delphinium Be Cut Back

Delphinium will benefit from deadheading the spent flowers. Cut the flower stalk that finishes blooming down to the side shoots if there is any. The plant will continue blooming throughout the summer.

If you have a long growing season or warmer zone, you can cut the plant back about an inch from the base, and it will encourage the second shoot to bloom. Make sure to clear up the old stalk and leaves, dispose of it to prevent fungus or any plant pests.

How To Harvest Delphinium Seed

You can also let the flower go to seed. Collect the seed when the pod is dry and turning into a brownish color. The pod usually open when the seeds are dry and ready to harvest.

To harvest the seed, gently shake the dried pod into the bowl, check them from any bugs before store it. You can also leave the seed there. By the following spring, you will get lots of new seedlings around the mother plant.

You can easily move these little seedlings around the garden. If there are too many seedlings, then you can share it with your gardening friends.

How To Overwinter Delphinium

Prepare the plant by cutting it back to the base, dispose of any old stalks and leaves. Do this before the hard frost is coming.

Cover the plant base with organic mulch like pine, bark, or straw to protect the plant crown. Remove the mulch in the early spring carefully when there is a sign that the plant shows the new shoot.

Add bone meal and compost in the spring around the plant base. Water the plant regularly, the dwarf variety is somewhat drought tolerant.

Pest On Delphinium

Slug like the tender delphinium shoots in the spring. To prevent this, I usually scatter broken eggshells around the plant base. The broken eggshells also works well to prevent slugs on hostas.

I often see the delphinium curl by itself. It usually contains a worm that eats the juicy new green shoot, and it makes the plant top shrivel. If you find the little black dropping around the leaves, it also indicates that the plant is infested by the worm.

To get rid of the worm, handpick them, and pluck the curled leaves. You have to check it often, as those worms might come back. Cutting back the plants before winter also removes the overwintered worm and cocoon.

Companion Plant For Delphinium

Because of the delphinium has tall flower spires naturally, it is excellent for the backdrop of the garden bed, by combining it with low growing plants. Lily, walker’s low catmint, roses, aster, chrysanthemum, peony are some of the perfect perennial flowers for delphinium companion plants.

Spirea, globe caragana, roses, hydrangea, and low growing evergreen are some of the shrubs you can grow with delphinium. Some annual plants like geranium, zinnia, marigold are great for continuous blooming too.

Here I grow delphinium against the back patio railing with Asiatic lily and walker’s low catmint. They all can bloom at the same time.

Once the lily finish, the catmints are still blooming up to fall season. And the delphinium will continue with the second flush of flowers.

Here are some of the reasons why you should grow delphinium in your garden.

The flower attracts bees and pollinators.
It adds texture to any flower bed.
The plant is an excellent addition to a cottage garden.
The long spire flowers are perfect for a cut flower arrangement.
Delphinium comes in a variety of colors, blue, baby blue, mauve, indigo, purple, white.
Easy to grow from seed.
Easy to propagate by root division.
Delphinium is self-seed readily.
Delphinium is hardy perennial zone 2-9, and will come back year after year with proper care.

Add this majestic flower for your garden this year! #perennialgarden #blueflowers Share on X