Grassy St. Johnswort
Hypericum gramineum · Hypericaceae
The gardener's calendar
Ideal time to plant grassy st. johnswort: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Blooming
- July to September, star-shaped yellow flowers
- Adult size
- 30 to 60 cm in height
- Growth
- Fast
- Hardiness
- Hardy, down to -15°C
- Origin
- Southern and central Europe
- Soil type
- Well-drained, tolerates poor soils
Care
Watering
Water regularly during growth and flowering, especially during dry periods. Once established, this species tolerates drought well. In winter, reduce watering. Let the soil dry slightly between waterings.
Light Exposure
Plant in full sun to partial shade. A minimum of 4 to 6 hours of direct sunlight promotes generous flowering. In very hot regions, light afternoon shade can be beneficial.
Pruning and Cleaning
Cut back the clump in spring (March-April) to encourage compact, bushy growth. Remove dried or damaged stems. Light pruning after flowering can stimulate a second wave of flowers.
Soil Preparation
Choose well-drained soil, slightly alkaline to neutral. This species adapts to poor and stony soils. Enrich moderately with well-decomposed compost in spring. Avoid standing water accumulation.
Fertilization
A balanced fertilizer application in spring is more than enough. Avoid excess nitrogen which would promote foliage at the expense of flowers. In poor soil, a moderate annual compost application is recommended.
Diseases and Pests
Generally very robust and rarely susceptible to diseases. Excess moisture can promote root rot: ensure optimal drainage. Occasionally watch for aphids, easily removed with a water spray.
Did you know?
The Hypericum genus is traditionally associated with Saint John's Day in Europe, where common St. John's Wort was hung above doors to ward off evil spirits. Its Latin name 'Hypericum' derives from Greek and literally means 'above an icon', referring to its supposedly protective properties in folk culture.
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
- Rose of sharonHypericum calycinum
- Tall tutsanHypericum inodorum
- Egyptian Saint John's WortHypericum aegypticum
- Hooker's St. JohnswortHypericum hookerianum
- Moser's St. John's wortHypericum moserianum
- Kalm's St. John's-wortHypericum kalmianum
Tips generated and checked by Viridia — adapt them to your local climate.