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How to Grow Delphiniums

How to Grow Delphiniums: A Must Read for Gardening Enthusiasts

Delphiniums are tall flowers that grow in a variety of colors. They are popularly used as garden borders. Here are some instructions on growing these flowers from basal cuttings and seeds.
Marian K
Last Updated: Mar 5, 2019
Honeybee pollinating Delphinium
Delphiniums are tall, spire-like flowers that can bring your garden to life with their many vibrant colors. Traditionally used in garden borders, but you can use them wherever you wish to add a splash of color.
Some common varieties are 'Black Knight' which is dark blue, 'Summer Skies' which is sky blue, 'Astolat' which is lilac-pink, 'Galahad' which is white, and 'King Arthur' which is violet-blue.
Blue Delphinium flowers
You can find them in several alluring shades of blue, from azure to purple. Also called "Larkspur", you can select the based on their height or color. These tall plants are usually six to eight feet tall, but smaller varieties exist such as the D. nudicaule 'Laurin' which is only 15'' tall.
How to Grow These Flowers?
Delphinium plants can be propagated by seeds or basal cuttings. You can choose the variety you would like to grow from a garden center or a catalog. Choose a spot that will get full sunlight (about six hours a day), and is shielded from the wind.
However, remember that they cannot be moved easily, which is why spot selection is important. The soil should be fertile and nutrient-rich, with good drainage. The right time to plant them is in the spring. Prepare the soil by mixing in 2 to 4 inches of compost.
From Potted Plants
Young Woman Loading Garden Seedling Potted Plants into Hatchback Car
If you buy a potted plant at the nursery, you can plant it in your garden by digging a hole twice the size of the pot. Carefully place the plant in the hole, and ensure that the top of the root ball is at the same level as the soil.
The plant should be positioned firmly and the foliage should be at ground level. Water the delphinium after planting, and continue to do so once a day until the plant has settled in. It needs plenty of water in the summer so be careful to not let it dry. Another tip is to broadcast lime, wood ashes, or a mixture of the two over the plant in the summer.
From Seeds
Growing this lovely flower from seeds is difficult. Seeds sown early indoors will flower in the first year. However, if sown outdoors, they will flower in the following year. For successful germination, it is best to use fresh seeds, which usually germinate in 2 to 4 weeks at temperatures of 65 to 75° F.
From Basal Cuttings
Growing this plant from basal cuttings can be done by cutting off new shoots which are about 3'' long with a knife. Ensure you cut right through their firm base tissue, and that the center of the stems are solid white, not hollow.
Make a straight cut under a leaf joint and then cut off the lower leaves so that you are left with a half bare stem. Expose the cut surfaces to a rooting hormone powder, and then place several cuttings around the edge of a pot filled with compost.
Ensure that you do not cover the base of leaf stalks. You could also place the cuttings in pearlite, sand, or a peat/sand mix. You can either place the pot in a windowsill propagator, or cover it with a plastic bag held in place by an elastic band.
Rooting should take place in two to three weeks. Once the roots appear, gently separate the cuttings, but try to retain some compost around the roots. Transfer the cuttings to large, individual pots, and you can plant them in your garden when they are strong.
The delphiniums' flowering season is from early in the year to midsummer. These plants also require appropriate care to flourish and grow healthy and strong. Part of this care includes stalking, which helps the plants stand. Apart from that, applying fertilizer during the growing season, thinning, and keeping an eye out for pests is important.