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Buchnera spp.
bluehearts
Tropical and warm-temperate worldwide
Overview
Buchnera is a genus of about 100 species of slender, hemiparasitic herbs in the broomrape family (Orobanchaceae), found across tropical and warm-temperate regions worldwide and known as bluehearts. The plants are partial root parasites: they make their own food by photosynthesis but tap the roots of neighbouring grasses and other plants for water and minerals. From a rough, often bristly stem 12 to 36 inches (30 to 90 cm) tall rise narrow, opposite leaves and a terminal spike of small tubular flowers. The flowers are typically blue to violet, sometimes white, about 0.4 to 0.6 inch (10 to 15 mm) across, with five spreading lobes. Most parts blacken as they dry, a feature shared across the genus. Buchnera grows in prairies, savannas, open pine woods, and seasonally moist grassland, depending on suitable host plants nearby. Flowering occurs through summer into autumn. Because of the parasitic root habit, the genus is difficult to grow away from its natural plant community and is rarely cultivated.
Native Range
Buchnera is widespread across the tropics and warm-temperate zones of the Americas, Africa, Asia, and Australia. B. americana, American bluehearts, is native to the central and eastern United States, growing in prairies, savannas, and open woodland.Suggested Uses
Grown mainly in prairie restorations, savanna plantings, and native grassland gardens alongside its host grasses, rather than as a stand-alone ornamental. The blue flower spikes add vertical colour among warm-season grasses. It suits naturalistic plant communities where host species are present.How to Identify
Appearance
Size & Dimensions
Height1' - 3'
Width/Spread6" - 1'
Reaches mature size in approximately 2 years
Bloom Information
Flowering runs through summer and into autumn, roughly June to September, with flowers opening a few at a time up the spike. The small tubular flowers are blue to violet, occasionally white. Bloom can continue for many weeks where moisture and host plants are available.
Detailed Descriptions
Flower Description
blue to violetFoliage Description
green, blackening when dryGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight