Complete Guide to Growing Larkspur Flowers
What is Larkspur?
Larkspur, also known as delphinium, is a beautiful cottage garden plant that adds height and color to borders. Its stunning flowers, which resemble dolphins (hence the name “delphinium”), come in a range of colors including blue, mauve, pink, white, and even red. Larkspur varieties can have single or double flowers, with single-flowered varieties being particularly attractive to bees.
How to Grow and Care for Larkspur
Larkspur thrives in moist but well-drained soil in full sun. Avoid planting in wet or heavy soil, as this can lead to problems. If necessary, add grit to the planting hole to improve drainage.
To grow larkspur successfully, follow these steps:
- Plant in spring or autumn when the soil is warm and moist.
- Plant at the same depth as it was growing in the pot.
- Water in well after planting.
- Stake taller varieties to prevent them from toppling over in the wind.
- Feed weekly with a high potash fertilizer.
- Cut back flower spikes after they have faded to encourage new blooms.
- Cut back the entire plant to the ground in autumn.
- Divide larkspur plants every few years in spring.
Where to Grow Larkspur
Larkspur grows best in full sun, so choose a spot in your garden that receives plenty of sunlight. Avoid windy areas, as strong winds can damage the tall stems.
Planting Larkspur
You can plant larkspur at any time of year, but spring or autumn is ideal. Plant the larkspur at the same depth as it was growing in the pot and firm the soil around it. Water well after planting.
Caring for Larkspur
Larkspur requires regular care to thrive. Here are some tips:
- Water regularly, especially during hot weather.
- Fertilize every two weeks with a liquid fertilizer.
- Stake taller varieties to prevent them from falling over.
- Cut back flower spikes after they have faded to encourage more blooms.
- Cut back the entire plant to the ground in autumn.
- Divide larkspur plants every few years in spring to keep them healthy and vigorous.
Propagating Larkspur
You can propagate larkspur from seed or cuttings. To grow larkspur from seed, sow the seeds in small pots or seed trays in February to June or September to October. Keep the seeds at a temperature of around 10-15°C.
To take cuttings, cut a new shoot from the base of the plant just below the soil surface in spring. Place the cutting immediately into a polythene bag to keep moisture in. Remove some foliage from the top of the cutting, leaving a few leaves to feed the roots. Pot up each cutting into a small pot filled with peat-free compost and perlite. Water and cover with a polythene bag or mist regularly to keep the leaves from drying out. Keep the cuttings in a greenhouse or on a sunny windowsill.
Troubleshooting Larkspur Problems
Larkspur can be affected by a few common problems, including:
- Slugs and snails: Protect new shoots from slugs and snails in spring, as they can damage the young growth.
- Powdery mildew: Keep the soil around larkspur moist to prevent powdery mildew in dry weather.
- Rust: Remove any affected leaves and clean up fallen leaves in autumn to prevent the spread of rust.
- Delphinium black blotch: This bacterial infection can cause large black blotches on larkspur leaves. Remove affected plants to prevent the disease from spreading.
Buying Larkspur
When buying larkspur, keep the following in mind:
- Choose a variety that is suitable for your garden conditions.
- Check the ultimate size of the variety before buying, as some larkspur can grow quite large.
- Buy larkspur from reputable nurseries or garden centers, or from specialist retailers online.
Larkspur Varieties
There are many different varieties of larkspur available, each with its own unique characteristics. Some popular varieties include:
- ‘Amadeus’: Deep-purple/blue flowers with a dark brown ‘eye’.
- ‘Pacific Hybrids’: Tall, stately larkspur plants in a range of colors.
- ‘Rising Stars’: Mixed variety with single or double flowers in a range of colors.
- ‘Magic Fountain Series’: Compact plants in a range of colors, suitable for smaller gardens.
- ‘Faust’: Incredibly tall spikes of intense blue double flowers, with a dark center.
- ‘Cinderella’: Compact, pale pink larkspur with very sturdy stems and triple blooms.