Purple gromwell
Glandora diffusa · Boraginaceae
📷 KENPEI · CC BY-SA 3.0
The gardener's calendar
Ideal time to plant purple gromwell: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Family
- Boraginaceae
- Plant type
- Herbaceous perennial
- Foliage
- Evergreen
- Flowering
- April to June
- Adult height
- Approximately 20 cm
- Exposure
- Partial shade
- Water needs
- Low
- Origin
- Mediterranean regions and Western Asia
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability medium.
Expert tips
The key tip
Spreading gromwell loves impeccable drainage and grows slowly. Water moderately in spring and stop after flowering (June).
The common mistake
Over-fertilizing or over-watering in summer: it rots quickly, especially after flowering.
The pro's trick
Sow it where you want to see it permanently because it hates being transplanted; its fine roots break easily and it doesn't recover well.
Care
Exposure
Spreading gromwell thrives in partial shade, ideally with a few hours of direct sunlight in the morning or late afternoon. It also tolerates partially shaded areas but will flower more abundantly with sufficient light. Avoid hot afternoon sun in very warm regions.
Watering
This plant has low water requirements once established. Water moderately at planting time, then reduce watering as the plant settles in. During prolonged dry spells, light watering every 2 to 3 weeks is sufficient. Allow the soil to dry between waterings to prevent root rot.
Soil
Spreading gromwell prefers well-draining, light, and lean soil. Arid or rocky soil suits it perfectly, reflecting its Mediterranean origins. Improve drainage with gravel or sand if your soil is too compact or clay-based.
Pruning and cleanup
Perform light deadheading (removal of spent flowers) to extend the blooming period. After flowering, you can lightly cut back the plant to maintain a compact shape. A cleanup of dead foliage in late winter is generally sufficient for this discreet species.
Fertilizing
No fertilizer is necessary for this frugal plant. A very modest application of compost in spring, just once, may suffice in very poor soil. Too much fertilization would encourage excessive leaf growth at the expense of flowers.
Pests and diseases
Spreading gromwell is generally very resistant. Excess moisture is its main risk, potentially causing root or fungal rot. Ensure good drainage and sufficient air circulation. No major pests typically affect it.
Did you know?
Spreading gromwell, though modest in appearance, belongs to the Boraginaceae family, renowned for its delicate flowers and historical medicinal properties. Its genus Glandora is less well-known than its cousins like borage or comfrey, but it shares that discreet beauty typical of Mediterranean plants adapted to arid environments. Its small glandular leaves give it a unique texture among rockery herbaceous plants.
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.
Add this plant to my garden →Plants from the same family
- BorageBorago officinalis
- Siberian buglossBrunnera macrophylla
- Pride of MadeiraEchium candicans
- Viper's buglossEchium vulgare
- ComfreySymphytum officinale
- Water forget-me-notMyosotis scorpioides
Tips generated and checked by Viridia — adapt them to your local climate.