Coronilla valentina aka Shrubby Scorpion Vetch

Coronilla valentina typically grows to 80cm-1m in both height and spread, forming a dense, rounded evergreen shrub. The subspecies glauca can reach up to 3m when trained against a wall. Growth rate is moderate, taking 10-20 years to reach full size. The plant maintains a compact, bushy habit with attractive blue-green pinnate foliage throughout the year.

Coronilla valentina is native to the Mediterranean Basin, with its range extending from Spain eastward to Dalmatia (modern-day Croatia). It naturally occurs in coastal areas, rocky limestone slopes, and scrublands throughout Southern Europe, the Balkans, North Africa (including Algeria, Morocco, and Libya), and Mediterranean islands like Corsica and Crete. The plant has been cultivated in England since 1596.

Coronilla valentina thrives in well-drained soil and is adaptable to various soil types including chalk, clay, loam, and sand. Good drainage is essential as the plant does not tolerate waterlogging. The plant tolerates a range of pH levels from acidic to alkaline, with a preference for neutral to slightly alkaline conditions matching its native limestone habitat.

Coronilla valentina is hardy to RHS H4, tolerating temperatures down to -10°C to -5°C (14°F to 23°F). It thrives in Mediterranean, subtropical, and temperate climates within USDA zones 8-11. While fairly hardy, it prefers warm, sheltered positions and may need winter protection in colder areas. The plant performs best with full sun and protection from cold winds.

Coronilla valentina can be propagated by seed or semi-hardwood cuttings. For seeds, scarify (chip) them first, then sow in mid-spring into soil with pH 6.5-7.5, keeping temperatures at 18-24°C (65-75°F). For cuttings, take semi-hardwood cuttings of about 10cm in late summer or autumn and root them in well-draining compost. Layering methods including simple layering and tip layering are also effective.

Coronilla valentina produces clusters of brilliant yellow, pea-shaped flowers from late winter through summer. The fragrant blooms appear in rounded umbel-shaped heads of 10-15 flowers, each about 1.5cm long. The cultivar 'Citrina' features pale lemon-yellow flowers from December to mid-spring. Flowers are followed by slender, curved seed pods containing 3-6 seeds.

Yes, Coronilla valentina is noted for its remarkably fragrant flowers. Linnaeus himself observed an interesting phenomenon: the flowers emit a sweet peach-like scent during the daytime but become almost scentless at night. This makes it particularly valuable for winter and spring gardens when fragrant plants are scarce. The cultivar 'Citrina' is especially prized for its rich, sweet fragrance.

The most notable variety is subsp. glauca, which is hardier than the type species and features intensely blue-grey (glaucous) foliage with 5-7 leaflets. Popular cultivars include 'Citrina' with pale lemon-yellow flowers (RHS Award of Garden Merit), 'Pygmaea' a dwarf form reaching only 45-60cm ideal for smaller gardens, and 'Variegata' with cream-edged foliage. Subsp. glauca can grow larger than the type, reaching up to 3m when wall-trained.

Coronilla valentina is strictly an outdoor plant, unsuitable for indoor cultivation. It thrives in USDA zones 8-11 and is hardy in most UK areas (RHS H4). Plant in a warm, sunny, sheltered position such as a south or west-facing wall border. It's excellent for Mediterranean gardens, coastal areas, rock gardens, and containers. In colder regions, grow against a warm wall or provide winter protection.

Coronilla valentina requires only light pruning and does not tolerate hard pruning. After flowering, lightly trim shoots to maintain shape and fit the available space. Never prune hard, especially during cold weather, as the plant may not recover. RHS classifies it as Pruning Group 1 (minimal pruning). The plant can appear straggly at times, but resist the urge to cut back severely.

Coronilla valentina has low fertilizer requirements as it is a nitrogen-fixing legume that can improve its own soil. The plant thrives in poor, stony, unimproved soils and excessive feeding can actually reduce flowering while promoting leggy growth. If growing in containers, a light application of balanced fertilizer in spring may be beneficial, but garden-grown plants typically need no supplemental feeding.

Coronilla valentina is generally trouble-free with few significant pest or disease problems. The main issues stem from cultural conditions rather than pathogens: root rot can occur in poorly drained or waterlogged soils, and winter dieback may happen in exposed positions or severe cold. Ensure good drainage and shelter to prevent most problems. The plant's toxic nature may deter some pests.

Coronilla valentina is pollinated by insects, particularly bees attracted to its fragrant, pea-shaped flowers. The bright yellow blooms produce nectar and are borne in clusters that make them highly visible to pollinators. The plant's strong daytime fragrance, noted since Linnaeus's observations, helps attract pollinating insects. After pollination, slender curved pods develop containing 3-6 seeds.

No, Coronilla valentina is NOT edible and is toxic to humans. The entire plant contains poisonous alkaloids (corolinine and catartine), with flowers and fruits being particularly dangerous. Ingestion can cause vomiting, diarrhea, abdominal pain, slow pulse, and in severe cases death. Do not consume any part of this plant under any circumstances.

While related Coronilla species have historical medicinal uses as diuretics and cardiotonics, Coronilla valentina should NOT be used medicinally due to its high toxicity. The plant contains cardiac glycosides and poisonous alkaloids that can cause serious harm or death. Any traditional medicinal applications are extremely dangerous and should only be considered under strict professional supervision, which is not recommended.

Coronilla valentina is primarily valued as an ornamental shrub, prized for its fragrant winter-spring flowers and evergreen blue-grey foliage. As a nitrogen-fixing legume, it can improve soil fertility, making it useful as a pioneer plant on poor, stony slopes. It's excellent for coastal gardens due to its tolerance of salt-laden winds, and performs well in Mediterranean-style gardens, rock gardens, and containers.