Innocence
Houstonia caerulea · Rubiaceae
The gardener's calendar
Ideal time to plant innocence: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Flowering
- Spring to early summer (April-June)
- Adult size
- 15-30 cm tall × 15-20 cm wide
- Growth
- Slow to moderate
- Hardiness
- Hardy, tolerates down to -15°C
- Origin
- North America (United States)
- Soil type
- Well-drained soil, slightly acidic to neutral
Care
Watering
Keep the soil lightly moist during growth, avoiding excess water that would promote rot. Reduce watering in winter. Prefer moderate and regular watering to prolonged soaking.
Light and exposure
Place your Houstonia in bright light, partial shade or sunny conditions depending on your climate. It appreciates locations without intense midday sun, especially in hot regions. Partial shade encourages prolonged flowering.
Soil and planting
Use a light, well-drained substrate mixed with horticultural compost and coarse sand if necessary. This plant dislikes stagnant moisture and prefers poor to average soils. Plant in spring, spacing plants appropriately.
Pruning and maintenance
Pinch young stems in spring to promote a bushy shape. After flowering, remove spent flowers to encourage another flush of blooms. Light cleaning of dead stems in late winter is sufficient.
Nutrient supply
Apply a light, balanced fertilizer in spring as vegetation starts. A single application is usually sufficient for the season. Avoid excess nitrogen, which would reduce flowering.
Diseases and pests
Houstonia is relatively hardy. Watch for powdery mildew in case of excessive humidity and poor air circulation. Limit risks through good air circulation and watering at the base of the plant.
Did you know?
Houstonia owes its common name to William Houston, an 18th-century British botanist who explored the flora of Central America and Mexico. Its tiny pale blue, almost white flowers have long fascinated landscape gardeners who appreciate it for creating delicate flowering carpets in rock gardens and woodland borders.
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.