Delphinium Information

One commonly thinks of delphinium plants (Delphinium) as having true blue flowers, which is the most common color. But numerous hybrids are available in shades of pink, lavender, red, white and yellow. Blooms may be single or double.

Delphinium planting is normally at the back of the bed, where flower spikes can reach 2 to 6 feet tall. Delphinium flowers are often planted in masses or groups. Shorter varieties are useful in other areas of the garden.

Planting Seeds

Fill a seed tray to within 1/2 inch of the top with sterile seed-starting compost. Mist the compost with water until the top 1 inch feels wet and let it soak in for five minutes before sowing the delphinium seeds.

Place the delphinium seeds on the surface of the compost, spacing them one inch apart. Cover them with a 1/4-inch-thick layer of seed-starting compost. Mist it with water and gently firm the surface.

Place the seed tray outdoors in a sheltered, lightly shaded garden area where temperatures stay between 65 and 75 degrees Fahrenheit during the day. Provide warmth with a propagation mat if the weather is unusually cool.

Maintain a light level of constant moisture in the top 1 inch of compost while the delphinium seeds germinate. Let the surface dry slightly between waterings to keep the seeds from rotting.

Watch for germination in 10 to 20 days. Water carefully after germination to prevent fungal infections. Drizzle the water directly onto the compost rather than watering from above.

Grow the delphinium seedlings in their nursery tray until they reach at least 1 inch tall and have two pairs of true leaves. Scoop out the seedlings and transplant them into individual 3-inch pots filled with potting soil.

Keep the delphinium seedlings well-watered for the rest of the summer. Feed them with 12-12-12 fertilizer diluted to one-fourth strength six weeks before transplanting them

Place the pots at the intended planting site every day. Extend the time by one hour every day for one week. This acclimates the delphiniums to normal outdoors conditions before you transplant them

Plant the delphiniums in a partly shady bed with deep, moist and fast-draining soil. Space the plants approximately one foot apart. Mulch heavily and water regularly during dry weather.