Polycarpon tetraphyllum aka Four Leaved Allseed

Polycarpon tetraphyllum prefers well-drained soil and is sensitive to overwatering. Water sparingly, allowing the soil to partially dry out between waterings. Root rot from excessive moisture is the most common issue with this species. In its natural habitat, it thrives in sandy, coastal soils with excellent drainage.

This species thrives in light, sandy, well-draining soil. It naturally grows in coastal sandy areas, gravelly sites, cracks in pavements, and disturbed ground. While it can tolerate a range of soil types including limestone soils, good drainage is essential to prevent root rot. A gritty, fast-draining mix mimics its natural habitat conditions.

Polycarpon tetraphyllum propagates primarily by seed. Sow seeds in well-draining soil during late spring or early summer, keeping them in a warm, bright location. Germination typically occurs within a few weeks. The seeds are tiny (0.4-0.5 mm) and can be surface-sown. In nature, seeds germinate in autumn to winter, with the plant growing through winter and flowering in spring.

Polycarpon tetraphyllum is a small, low-growing annual that typically reaches 3-15 cm (1-6 inches) in height. It has a spreading, prostrate growth habit with much-branched stems that can spread up to 20 cm. The plant has a fast growth rate, completing its entire lifecycle in one growing season. It germinates in autumn-winter, grows through winter, and flowers from spring to summer.

Polycarpon tetraphyllum is native to southern Europe and the Mediterranean region. DNA studies suggest it probably originated in the Mediterranean where the genus is most diverse. The species has since spread globally and is now naturalized in North and South America, Australia, New Zealand, Japan, parts of Africa, and is present on every continent except Antarctica.

Yes, Polycarpon tetraphyllum produces small white flowers in loose clusters at the ends of stems. Each flower has 5 tiny white petals and 5 sepals, with 3-5 stamens. The flowers are self-pollinating and often cleistogamous, meaning they can fertilize themselves without fully opening. Flowering occurs from spring to summer in temperate regions, though in Mediterranean climates it may flower year-round.

Polycarpon tetraphyllum is primarily self-pollinating. The flowers are homogynous (having male and female parts mature simultaneously) and automatically self-pollinate. Many flowers are cleistogamous, meaning they self-fertilize without ever opening. This reliable self-pollination contributes to the species' success as a prolific seeder that doesn't depend on pollinators.

Polycarpon tetraphyllum is exclusively an outdoor plant, thriving in USDA hardiness zones 8-11. It grows naturally in coastal areas, waste ground, lawns, roadsides, and disturbed habitats. In the UK, it is native to mild areas like the Scilly Isles and Cornwall. The species prefers full sun to partial shade and well-drained sandy soils. It is frost-sensitive and grows best in Mediterranean-type climates.

Polycarpon tetraphyllum tolerates moderate humidity levels and is adaptable to various conditions. As a plant native to Mediterranean and coastal habitats, it can handle both dry and moderately humid environments. Good air circulation is beneficial to prevent fungal issues, especially in more humid conditions.

Polycarpon tetraphyllum has low nutrient requirements, thriving naturally in poor, sandy soils and waste ground. If desired, a balanced fertilizer (10-10-10) can be applied sparingly to support growth. However, this weedy species typically grows well without supplemental feeding. Over-fertilizing is unnecessary and may encourage leggy growth.

Polycarpon tetraphyllum prefers moderate to warm temperatures, thriving in USDA zones 8-11 (minimum temperatures around -12°C to 4°C / 10°F to 40°F). It is frost-sensitive and grows best in Mediterranean-type climates. The species germinates in cool autumn-winter temperatures but requires warm spring conditions for flowering and seed set.

Polycarpon tetraphyllum is an annual that follows a specific seasonal cycle. Seeds germinate in autumn to winter, the plant grows through winter and spring, then flowers in spring to summer before setting seed and dying back. In frost-prone areas, protect young plants or grow as a warm-season annual. No dormancy period care is needed as the plant completes its lifecycle in one season.

Polycarpon tetraphyllum is generally a hardy species with few documented pest or disease problems. The main issue is root rot from overwatering, which can cause leaves to curl, droop, or yellow. Ensure well-draining soil and avoid waterlogged conditions. As a wild/weedy species, it has evolved to be relatively pest-resistant.

Yellow leaves on Polycarpon tetraphyllum are most commonly caused by overwatering and root rot, as this species is sensitive to wet soil. Less often, yellowing results from underwatering, nutrient deficiencies, or natural aging. Check that the soil drains well and reduce watering frequency. If the plant is mature and flowering, some yellowing is normal as the annual completes its lifecycle.

With a bit of knowledge and dedication, you can successfully care for Four Leaved Allseed, making it a rewarding choice for those seeking a moderate challenge.

To ensure optimal growth, the Four Leaved Allseed prefers bright indirect light for 6-8 hours each day. Insufficient light can result in slow growth and leaf drop, so it's important to find a well-lit location for this plant. Place it near a window, within a distance of 1 meter (3 feet), to enhance its potential for thriving.

There is no verified data on the toxicity of this plant in the records of Ploi. If any person, including yourself, a family member, or a pet, consume plant material with an uncertain toxicity level, it is advisable to seek the advice of a healthcare expert.