Columbine (also known as Granny's bonnet) is known for its distinctive, bell-shaped, spurred flowers, which bloom from mid-spring to early summer. Though individual plants are short-lived, lasting only two to three years, columbine self-seeds prolifically and will persist in the garden with volunteer seedlings. With a wide choice of hybrid varieties, colors range from light pastels to bright yellow, red, orange and purple selections. The plant foliage is has an attractive lacey appearance.
Special features of columbines
Aquilegia 'Snow Queen' is well known for its striking , pure white spurred flowers.
Aquilegia vulgaris 'Adelaide Addison' displays bi-color white and blue flowers in the early summer.
Aquilegia vulgaris 'Nora Barlow' has attractive double spurless flowers in red, pink and pale green.
Choosing a site to grow columbines
In most climates, columbines grows best in full sun and well-drained, fertile soil but in warmer climates, full sun in the morning and partial shade in the afternoon is preferred.
Plant in spring, spacing plants 1 to 3 feet apart, depending on the variety. Prepare the garden bed by using a garden fork or tiller to loosen the soil to a depth of 12 to 15 inches, then mix in a 2- to 4-inch layer of compost. Dig a hole twice the diameter of the pot the plant is in. Carefully remove the plant from its container and place it in the hole so the top of the root ball is level with the soil surface. Carefully fill in around the root ball and firm the soil gently. Water thoroughly.
Columbine is prone to a fungal disease called powdery mildew. The spores spread through splashing water and travel on wind currents to infect other plants. Once established, powdery mildew is difficult to control. Most fungal diseases develop during rainy, wet weather, but powdery mildew develops when daytime temperatures are warm and nights are cool. The disease is not dependent on water on the leaves. You can help your columbines resist the disease by cutting back the affected plant parts (down to ground level if necessary), providing afternoon sunshine, and lots of air circulation in and around the plants.
One of the most common pest on columbine is leaf miner. These fly larvae feed inside the leaf. You'll see their damage as light-colored, winding tunnels on the leaf surfaces. Cut off and destroy all infested foliage after plants have bloomed; the new leaves that regrow later in the season will be miner-free.