Overview
Collomia grandiflora is a plant with a clump-forming habit in the genus Collomia, part of the Polemoniaceae family, with deciduous foliage. Collomia grandiflora grows best in full sun, and tolerates loam soils and neutral pH. Its UK hardiness is rated H3. Suggested uses include border plant and ground cover.
About
Collomia grandiflora is a western North American annual plant in the phlox family (Polemoniaceae), known by the common names grand collomia, large-flowered mountain trumpet, and large-flowered collomia. It usually appears in sandy habitats and is cultivated as an ornamental. In the wild it grows across North America, Arizona, British Columbia, California, Colorado and other regions. Grow it in full sun and loam soil. In UK gardens it is half-hardy and may need winter protection in colder areas (RHS H3). It works well for border plant and ground cover. It tolerates neutral soils, well-drained conditions and south-facing aspects. Plant in well-drained soil in a suitable position. Water during establishment.
Wikipedia contributors, CC BY-SA 4.0 — Collomia grandiflora
Growing conditions
Best soil and position for Collomia
- Sunlight
- Full sun
- Soil type
- Loam
- Soil pH
- Neutral
- Soil moisture
- Well-drained
- Aspect
- South-facing
- Exposure
- Sheltered
- UK hardiness
- H3
Plant details
Collomia grandiflora size, habit and characteristics
- Habit
- Clump-forming
- Foliage
- Deciduous
- Suggested uses
- Border plant, ground cover
Care notes
Pruning and caring for Collomia grandiflora
- Propagation
- Seed, division
- Pest resistance
- Generally pest-free
- Disease resistance
- Generally disease-free
Frequently asked questions
Where is the best place to plant Collomia grandiflora?
Collomia grandiflora prefers full sun. It suits sheltered positions.
What soil does Collomia grandiflora need?
Collomia grandiflora grows best in loam soil. It prefers neutral soil. Aim for soil that stays well-drained.
Is Collomia grandiflora hardy in the UK?
Collomia grandiflora has an RHS hardiness rating of H3, meaning it is half-hardy, tolerating -5 to 1°C, and may need winter protection in colder areas.
How do I propagate Collomia grandiflora?
Seed, division.
