How to Get Delphiniums to Bloom Twice in One Season

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If you want a second set of blooms after your delphiniums have flowered, use this simple method to encourage additional blooms.

For more delphinium growing tips, also see Delphiniums: Growing Tips and Tricks.

Delphiniums and other flowers in the garden.

How to Make Delphiniums Bloom Twice in One Season

How long do delphiniums bloom?

How long delphiniums bloom depends on the plant and growing conditions. Generally, delphiniums flower for several weeks until the blooms start to die off and seed production begins. Bloom time may be hastened by wind and rain breaking stems and damaging flowers. Ongoing moderate, sunny conditions with adequate water may extend bloom times.

Purple flowering delphinium. — Delphinium flowers protected with bamboo support posts

Depending on the variety you are growing and your location, delphiniums can start blooming in late spring or early summer with the right growing conditions.

These tall, magnificent flowers often come into bloom around summer solstice and continue flowering for several weeks, unless winds or rain damage them first. Growing in a sheltered location with support posts and foam wire are recommended for this reason.

Once the first set of blooms is finishing up—or you’ve taken cut flowers—if you still have a couple months before the risk of fall frosts, there is probably enough time to encourage a second set of blooms.

Here’s how it works. You have to be brave. When a delphinium has finished blooming, if left alone, the flower head is going to gradually turn to seed.

To get second blooms, you forgo seed production and instead remove the stem. Cut back to the base of the plant, the delphinium can then put its energy into new growth.

I’ve provide more details below.

How to Make Delphiniums Bloom Again

Other Flowering Plants That Can Bloom Again

How to Save Delphinium Seeds

Resources

How to Make Delphiniums Bloom Again

Delphinium seeds - If you love delphiniums and wish the beautiful, tall, blue flowers would last throughout the summer. They do not, of course, but with this simple tip, you can actually get these gorgeous, flowering giants to bloom a second time within the same growing season. — Blue delphinium in bloom

Your delphiniums have produced a beautiful first set of flowers and now you want more!

Getting a second set of blooms is a bit of a race against time. The more time you have before your anticipated first frost, the better.

As soon as the flowers pass their peak (start to wither and die off), you have to remove the entire flower stalk. By doing this, the plant will now put all its energy into sending up more flower shoots instead of working on seed production. It also just makes the plant look nicer.

Cutting delphinium flower stalks. — Cutting off delphinium flower stem at base of plant

To remove the old flowers, follow a stalk all the way to the base of the plant and cut it off as close to the base as possible. Do not remove any surrounding leaves or foliage.

It’s a bit sad to do—the aging blooms can be so pretty—but it helps the plant put its resources into additional blooms.

Light blue delphiniums. — Delphiniums producing second blooms late in the growing season

The sooner I snip off the first set of blooms, the more success I seem to have with round two.

And that’s it. You should see new shoots within a week or two. It does not always work though, so don’t be disappointed. If I trim back 10, perhaps 5 or 6 will flower again.

If you have several plants, you can always choose the best ones for seed saving and trim the rest for second blooms.

Seeds stored in mason jar and in plastic photo cases.

Other Flowering Plants that Can Bloom Again

Pink bleeding heart flowers. — Pink bleeding heart flowers

Cutting back or deadheading first blooms to get second blooms can also work for other perennials including:

Bleeding heart
Coneflower
Daisies
Lupine
Phlox

and, many flowering annuals.

Salvia
Veronica
Sage
Yarrow

How to Save Delphinium Seeds

Delphinium producing seeds on old flower stalk. — Delphinium during seed production cycle

If you want to save seeds from your delphiniums, do not cut them back. Instead, let the plant to go through its natural cycles. After flowering, the plant will transition to seed production.

This explains how to save seeds from your garden plants and store them for future sowing. You may also hear it called seed collecting or harvesting—these are all the same thing—keeping seeds for sowing later.

In nature, seeds naturally fall to the ground when ready and, if conditions are right, will germinate in the future. By collecting and storing them, we can control the process.

Resources

Delphinium | Genus: Delphinium

Various colors of flowering delphiniums.

Herbaceous perennial
• Hardiness zones 3a to 8b
• Full or part sun
• Well-draining loam is best
• Native to North America and African mountains and considered non-invasive
• Chill dampened seeds prior to sowing for better germination rates