Eryngium integrifolium aka Blueflower Eryngo

Eryngium integrifolium is relatively easy to grow when provided with its preferred conditions. The main requirement is consistently moist to wet soil, as this is a facultative wetland species. It adapts well to container culture and can even grow in shallow water like a pond marginal. Once established, it requires minimal maintenance beyond ensuring adequate moisture during dry periods.

This species requires consistently moist to wet conditions and should never be allowed to dry out completely. In garden settings, water regularly to maintain soil moisture, especially during hot or dry periods. The plant can tolerate standing water and even grow directly in shallow water like a pond marginal. Florida Wildflower Foundation notes it 'may need extra watering' when grown in typical garden conditions rather than its native wetland habitat.

Eryngium integrifolium thrives in moist, acidic, sandy soils typical of its native pine savanna and flatwood habitats. Ideal soil is nutrient-poor, well-aerated sandy loam or sandy peat that retains moisture without becoming waterlogged. The plant is adapted to the challenging conditions of southeastern coastal plain soils and does not require rich or heavily amended growing media. Avoid heavy clay soils that may cause root rot.

Eryngium integrifolium performs best in full sun but tolerates partial shade. In its native habitat of open pine savannas and flatwoods, it receives abundant direct sunlight. For optimal flowering and compact growth, provide at least 6 hours of direct sunlight daily. Plants grown in too much shade may become leggy and produce fewer flower heads.

Eryngium integrifolium can be propagated from seed, division, or root cuttings. Seeds benefit from cold stratification and should be sown on the soil surface as they require light for germination. Expect germination in 5-90 days at around 20°C. Division can be done in early spring or fall by separating the root mass. Root cuttings taken in mid to late autumn when the plant is dormant are also effective, though be careful not to disturb more than one-third of the taproot system.

Eryngium integrifolium grows 1 to 3 feet tall with a spread of about 1 foot. The deep taproot can extend up to 2 feet into the soil, spreading laterally 1-2 feet. The plant typically reaches full size within 2 years and has a lifespan of 3-5 years. Its upright growth habit features multiple blue flower stalks rising from a basal rosette of succulent leaves.

Eryngium integrifolium produces numerous compact, thimble-shaped flower heads from late summer through fall, typically August to October. The small heads measure less than half an inch wide and display striking blue to violet coloration, making this one of the showiest members of its genus. Each flower head is surrounded by a whorl of stiff, spiny bracts. After blooming, the persistent seed heads provide continued ornamental interest through winter.

Eryngium integrifolium is an exceptional pollinator plant, attracting a wide diversity of insects including native bees, flies, and beetles. The species is considered of special value to native bees since it attracts large numbers to feed on nectar. The late summer to fall blooming period makes it particularly valuable when many other nectar sources have finished flowering. The flowers are self-fertile, meaning a single plant can produce viable seed.

Eryngium integrifolium is native to the southeastern United States, ranging from southeast Virginia and eastern North Carolina south through Florida and west to Texas and Oklahoma, with populations extending inland to central Tennessee. Its native habitats include pine savannas, pine flatwoods, seepages, wet meadows, and boggy depressions with moist, nutrient-poor, acidic sandy soils. It is documented at several National Wildlife Refuges including San Bernard (TX), Carolina Sandhills (SC), Okefenokee (GA), and St. Marks (FL).

Eryngium integrifolium is hardy in USDA zones 6 through 10, covering most of the southern and mid-Atlantic United States. The plant thrives outdoors in areas with warm summers and mild winters. It requires a site with full to partial sun and consistently moist to wet soil. In areas at the northern edge of its range, ensure good drainage to prevent root rot during winter wet periods.

Eryngium integrifolium is generally pest and disease resistant when grown in appropriate conditions. The main pest concern is deer, which find the succulent leaves palatable according to the Florida Wildflower Foundation. The spiny bracts around the flower heads provide some protection from browsers. Overwatering in poorly drained soil can lead to root rot. No serious insect pests or diseases are commonly reported for this species.

Ploi lacks confirmed information on the toxicity of this plant. If you, a relative, or your pet accidentally consume plant material with unknown toxicity, it's best to consult a medical expert.