Growing and Caring for Diascia (Twinspur): A Comprehensive Guide
Plant Overview
Diascia, also known as twinspur, is a delicate and charming plant native to South Africa. It is a popular choice for containers and hanging baskets due to its compact size and attractive blooms. Diascia is a versatile plant that can be grown as an annual or a short-lived perennial in warmer climates.
Varieties and Characteristics
The genus Diascia comprises approximately 70 species, ranging in size from 6 to 12 inches tall and 18 inches wide. Some popular varieties include:
- Diascia barberae ‘Blackthorn Apricot’: Soft pink flowers
- Diascia ‘Picadilly’: Large white flowers
- Diascia ‘Flirtation Orange’: Soft orange flowers
- Diascia integerrima ‘Coral Canyon’: Salmon-pink flowers
- Diascia personata: A species with pink flowers that can reach up to 4 feet tall
Growing Conditions
Light: Diascia prefers full sun but can tolerate partial shade, especially in hot climates.
Soil: The plant thrives in well-drained, slightly acidic soil with a pH between 6.0 and 6.5.
Water: Diascia requires regular watering, but it is important to avoid overwatering. Allow the top inch of soil to dry out before watering again.
Temperature and Humidity: Diascia prefers cooler temperatures and blooms best in the spring and fall. It is somewhat frost-tolerant and can survive light frosts.
Fertilizer: A slow-release fertilizer applied once a month during the growing season will help promote healthy growth and abundant blooms.
Care and Maintenance
Pruning: Diascia does not require deadheading, but it can be pruned back by half if it becomes leggy or spent. This will encourage new growth and blooming.
Propagating: Diascia can be propagated from cuttings taken in the spring or fall.
Growing from Seed: Diascia seeds are rarely available, but they can be sown indoors 6-8 weeks before the last frost.
Potting and Repotting: Diascia is well-suited for containers. Use a well-draining potting mix and ensure the container has adequate drainage holes. Repotting is generally not necessary.
Overwintering
In USDA zones 9 through 11, diascia can survive the winter as a short-lived perennial. In colder climates, it is grown as an annual and cannot be overwintered.
Common Pests and Diseases
Diascia is generally disease-resistant, but it can be susceptible to pests such as snails and slugs. These pests can be controlled by lifting the plants off the ground or using snail and slug bait.
Troubleshooting Common Problems
- Lack of Blooms: Insufficient sunlight or fertilizer can inhibit blooming. Apply a phosphorus-rich fertilizer to encourage flowering.
- Leggy Growth: Over-fertilizing or insufficient light can lead to leggy plants. Reduce fertilizer frequency and ensure the plant is receiving adequate sunlight.
- Yellowing Leaves: Overwatering or poor drainage can cause yellowing leaves. Allow the soil to dry out before watering again and improve drainage if necessary.
Additional Tips
- Companion Planting: Diascia pairs well with other plants that prefer similar growing conditions, such as lobelia, alyssum, and verbena.
- Attracting Butterflies: Diascia flowers are a magnet for butterflies, making it a great choice for attracting these pollinators to your garden.
- Using as a Spiller: Diascia’s trailing habit makes it an ideal choice for use as a spiller in mixed containers or hanging baskets.
