Overview
Alliaria petiolata is a bushy annual biennial in the genus Alliaria, part of the Brassicaceae family, with evergreen foliage. It typically grows around 0.5-1 metres tall and 0.1-0.5 metres wide, reaching full size in around 1-2 years. Alliaria petiolata grows best in full shade and partial shade, and tolerates most soils and any pH. Its UK hardiness is rated H6. It is attractive to pollinators. Suggested uses include wildlife gardens.
About
Alliaria petiolata is a biennial herb characterized by its hairy texture and variable height. Typically unbranched, it features green leaves that range from heart to kidney shapes, releasing a strong garlic scent when crushed. The plant produces small white flowers, measuring 3-5 mm in diameter, which cluster at the ends of the stems. Its seed capsules are elongated and slender, measuring between 20 and 70 mm in length.
About the genus
Alliaria includes annuals, biennials, and perennials. The plants feature garlic-scented, ovate or heart-shaped foliage and produce racemes of small, four-petaled white flowers during the spring season.
Growing conditions
Best soil and position for Alliaria
- Sunlight
- Full shade, Partial shade
- Soil type
- Chalk, Loam, Sand
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Moist but well-drained
- Aspect
- East-facing, North-facing, West-facing
- Exposure
- Exposed, Sheltered
- UK hardiness
- H6
Plant details
Alliaria petiolata size, habit and characteristics
- Plant type
- Annual Biennial
- Habit
- Bushy
- Foliage
- Evergreen
- Height
- 0.5-1 metres
- Spread
- 0.1-0.5 metres
- Time to full height
- 1-2 years
- Suggested uses
- Wildlife gardens
- Fragrance
- Foliage
Care notes
Pruning and caring for Alliaria petiolata
- Cultivation
- Prefers a rich damp alluvial soil, thriving in damp shady places where few other herbs will grow. A good woodland-edge and hedgerow plant, the plant emits a strong smell of garlic which is especially pronounced if the leaves are bruised. This species is an important food source for the orange-tip and green-veined-white butterflies
- Pruning
- No pruning required
- Propagation
- Propagate by seed as soon as ripe. If sowing in situ, it is best to sow in autumn as it requires a long period of chilling to break dormancy
- Pest resistance
- Susceptible to caterpillar damage
- Disease resistance
- Generally disease-free
Frequently asked questions
How do I grow Alliaria petiolata?
Prefers a rich damp alluvial soil, thriving in damp shady places where few other herbs will grow. A good woodland-edge and hedgerow plant, the plant emits a strong smell of garlic which is especially pronounced if the leaves are bruised. This species is an important food source for the orange-tip and green-veined-white butterflies.
Where is the best place to plant Alliaria petiolata?
Alliaria petiolata prefers full shade and partial shade. It suits exposed and sheltered positions.
What soil does Alliaria petiolata need?
Alliaria petiolata is adaptable and grows happily in most soil types, including chalk, loam and sand. It is happy in soil of any pH. Aim for soil that stays moist but well-drained.
How do I prune Alliaria petiolata?
No pruning required.
How big does Alliaria petiolata grow?
Alliaria petiolata reaches a height of 0.5-1 metres and a spread of 0.1-0.5 metres. It takes around 1-2 years to reach full size.
Is Alliaria petiolata hardy in the UK?
Alliaria petiolata has a UK hardiness rating of H6.
How do I propagate Alliaria petiolata?
Propagate by seed as soon as ripe. If sowing in situ, it is best to sow in autumn as it requires a long period of chilling to break dormancy.
Is Alliaria petiolata good for pollinators?
Yes — Alliaria petiolata attracts and supports pollinators such as bees and other beneficial insects.