Delphinium, also known as Larkspur, is a member of the genus Ranunculaceae family of flowers. This perennial is known for its tall spike-like spurred columns of showy flowers in colors including red, blue, yellow and white. The delphinium plant is highly toxic and can cause death if sufficient amounts are ingested. The leaves of the delphinium plant have 3 to 7 teeth on deeply formed lobes reminiscent of a maple leaf. The stems can range from 4 to 6 inches and 1/2 foot tall. The flowers have 5 petals, which form the spur that gives the plant its name.
Most varieties of delphinium prefer humus-rich, fertile, moist soil. Partial shade should be provided in hot areas and the soil should be well drained.
Delphinium has been used in herbal medicine for centuries.Tall delphiniums can be used a focal points in borders or as accents against hedges and buildings.Delphiniums make lovely cut flowers in flower arrangements by themselves or with other flowers.
Choosing a Variety
Choose delphiniums based upon the intended use in the garden. The smaller delphinium plants can create borders and accents in any garden scheme, while the larger plants add emphasis and highlights where needed.
Delphinium can be grown from seed or from established plants from the nursery or garden center. Seeds should be started in 6-inch pots with 2 to 4 seeds per pot. Press the seeds into the soil and cover. Thin to 2 plants per pot.Potted delphinium plants should be transplanted in late April into prepared beds. Dig holes approximately 7 inches deep and 4 inches around. Add a light fertilizer or compost to the bottom of the hole. Carefully remove the plants from the container and place in the hole, gently shaking the roots to loosen. Space delphinium plants 1 foot apart. Cover and water thoroughly to remove any air pockets from around the roots.
Delphinium plants should be staked to keep them erect. Pound a stake several inches away from the plant and tie loosely with plant tape or sections of old panty hose. A light fertilizer can be applied to the plants in the early spring. Remove any remaining stems from the previous season before the new growth begins in the late spring. Delphiniums require the equivalent of 1 inch of water weekly to thrive.Remove deadheads to encourage the plant to rebloom. Delphiniums, because of their alkaloid properties, are unlikely to have insect pests, and if spaced appropriately are very disease resistant.Seeds can be collected from the spent buds in mid to late fall.