How to Grow Larkspur

Larkspur, or Delphinium, is a beautiful and popular annual that comes in colors of blue, lavender, white, rose, and pink. It has lacy foliage with highly compacted blooms on long tapering spikes, giving it a tall, regal appearance. It generally grows in 1 or 2-foot high spires, although some plants reach heights of up to four feet and taller. It makes an excellent garden flower, and also looks great in vases. Follow these steps to grow your own.

TIP: Our expert gardening advisor, Karen Thurber adds, "Larkspur was recently changed from the genus Delphinium to the genus Consolida."

Step 1 - Pick the Right Spot and the Right Time

Pick a spot with full sunlight or partial shade. Most people grow it along a fence, use it for borders, or plant it in drifts. The soil should be average to rich and also well-draining. If you live in a colder area, you can plant in early spring; otherwise it is best to plant in the fall, usually October or November. Since seedlings don’t transplant well it is best to sow the seeds directly in the ground.

Step 2 – Sow the Seeds

Cover the seeds lightly. The seeds must be close to the surface, because to germinate they need a lot of sunlight. It is best to only scratch them into the soil. Four inches apart is generally enough space, and do not put a lot of mulch on them. For optimum growth, it is best to group them into sections of 10 or 20 plants. It will take about a week for the seeds to germinate, so be sure to keep them moist during this time.

During winter larkspur, develop their root systems, and the next spring they go into a blossoming frenzy.

TIP: Karen advises, "Seed from Larkspur can be collected and saved for planting next year. Allow the flowers to go to seed, collect the tiny black seeds on a dry day, and store them in a cool, dry location. Saved seed retains it's viability for up to 6 months, after which time it starts to decline. Year old seed can have germination rates as low as 50 percent."

Step 2 – Water

Remember to keep the soil watered well to feed their fast growth. Larkspur requires a lot of water, but soggy soil will cause it to rot — if you have an especially dry period, water them 2 to 3 times per week.

Step 3 – Thin Seedlings

Wait until about two leaves appear on each plant and then thin them out to six inches apart. If excessive heat causes any plants to wilt, simply pluck them out and discard.

Step 5 - Maintain

Larkspur generally grows best in cooler weather. When the temperature rises to 80 degrees and higher, they will most likely die. But in general, it will grow fast with little maintenance until the first frost hits. As with most annual plants, frost will wipe them out. Also strong winds will damage them, so make sure they are well-shielded. If your larkspur grows too tall, it may have to be staked up as the blossoms get too heavy. But, if they are planted about six inches apart, they will support one another and won’t require staking.

Larkspur usually blooms very early in the spring, before any other plants. If you need to add fertilizer to your soil, do so about once a month, but not after the larkspur have bloomed.

Step 6 – Cut Flowers

If you want cut flowers for vases, wait until about half of the flowers have fully opened before cutting, just before the blooms reach full maturity. To dry out your larkspur, simply hang it upside down in a dark dry place with plenty of air circulation. It is great used in arrangements with other flowers, or simply by themselves.

Pests and Disease

Sclerotium rot is the most common disease you will have to worry about with larkspur. It makes the plants wilt and turns the leaves yellow. If you notice your plants infected with it, immediately use a common fungicide to treat them. You should also pluck out any damaged larkspur and throw it away.

You shouldn’t have a major problem with insects, although aphids are sometimes a nuisance. Simply use your favorite organic insecticide if you notice a pest problem.

Caution

Be aware that all parts of larkspur, even the seeds, are highly toxic and are poisonous to many animals, especially cattle. Ranchers occasionally have problems moving herds to locations where larkspur grows wildly. If the cattle eat the larkspur, it will kill them.

Growing your own larkspur is as easy that. Plant and enjoy them in your own garden!

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