Tweedia
Oxypetalum caeruleum · Apocynaceae
⚠️ Tweedia : plante entière contient cardenolides. Ingestion provoque troubles digestifs, troubles cardiaques graves chez chiens/chats ; toxique pour enfants.
The gardener's calendar
Tweedia is in full bloom: enjoy it, watch watering in hot weather and let spent flowers feed pollinators before pruning.
ID card
- Common name
- Tweedia
- Family
- Apocynaceae
- Form
- Herbaceous
- Flowering
- June to September
- Adult size
- Approximately 150 cm in height
- Foliage
- Semi-evergreen
- Hardiness
- Low hardy, best grown in mild climates or in containers
- Origin
- South America (Brazil, Uruguay)
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability medium.
Expert tips
The key tip
Well-draining, moist soil in full sun; this twining climber needs an airy support (trellis) to thrive. Water regularly during growth (May-August), moderately in winter.
The common mistake
Overwatering in winter or planting in heavy soil: the plant yellows and blue flowers abort.
The pro's trick
Pinch back the tips in June: this forces branching and multiplies flowering points over a denser surface.
Seasonal watch
In autumn (September-October), watch the foliage: yellowing = excess water.
Care
Light exposure
Place your tweedia in full sun to encourage abundant flowering and vigorous growth. It tolerates very bright locations and benefits from at least 6 hours of direct sunlight daily. In hot regions, light afternoon shade can prevent leaf scorching.
Watering
Water regularly during the growth and flowering periods, keeping the soil moist but not waterlogged. Allow the soil surface to dry slightly between waterings. Reduce watering in winter or during dormancy.
Soil and potting mix
Use rich, well-draining potting soil that is slightly acidic. A mixture of universal potting soil with some perlite or sand improves drainage and prevents root rot. Always ensure your pot has drainage holes.
Fertilizing
Apply a balanced fertilizer or one slightly higher in phosphorus every 15 days during the flowering period (June to September). Stop fertilizing in autumn and winter. A soluble fertilizer diluted in your watering can is effective and convenient.
Pruning and maintenance
Pinch back young stems in spring to encourage branching and a more bushy shape. Remove spent flowers regularly to extend the flowering period. Prune lightly in late winter to keep the plant compact.
Diseases and pests
Tweedia dislikes excessive moisture which can promote root rot or fungal diseases. Ensure good air circulation and avoid wetting the foliage when watering. Watch for spider mites in dry environments and ventilate regularly.
Did you know?
Botanists are fascinated by tweedia's spectacular floral transformation: its buds open in vibrant turquoise-blue, then the flowers gradually shift through violet and pink hues, creating a remarkable color gradient on a single plant. This natural chromatic mutation earned it the poetic nickname of "the flower that changes its dress." In South America, it has long been cultivated as a cut flower for the richness and originality of this ever-changing color palette.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
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Tips generated and checked by Viridia — adapt them to your local climate.