Species Roundleaf Thorowax
yellow-lime flowers with light-green stems and green leaves

Roundleaf Thorowax

Bupleurum rotundifolium

Also Known As - Hare's Ear
Roundleaf Thorowax is a perennial plant found in many regions of the world. It has a basal rosette of bright green, slightly toothed, round leaves that form a dense mass up to 30 cm tall. The yellow flowers are small, urn-shaped and clustered in umbel-shaped inflorescences. It is a low-maintenance perennial, needing little attention and growing in sun or shade, as long as there is well-draining soil. It is drought tolerant and perfect for xeriscaping. The Roundleaf Thorowax is an ideal choice for pollinator gardens, attracting bees and butterflies. It is also an excellent species for attracting beneficial insects.




Division,Root Cutting,Seed Propagation,Layering Propagation

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full sun,part shade



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The Roundleaf Thorowax, Bupleurum rotundifolium, requires regular watering throughout the growing season. In spring and summer, it should be watered deeply approximately once a week. The soil should be allowed to dry out a bit between waterings. During the fall and winter months, the plant should receive less water. It is recommended to wait for the soil to become dry to the touch before providing the plant with 1 or 2 deep waterings throughout the month. Additionally, make sure to keep soil evenly moist, but not soggy, so it remains well aerated.


Roundleaf Thorowax is an annual plant, native to Europe, that thrives in sunny areas with well-drained soils. It prefers full sunlight, though it can tolerate some shade. It needs at least 6 hours of direct sunlight a day to thrive and bloom, and prefers full sun during the majority of the day. It should be planted in an area with no more than partial shade during the day, such as near a south-facing window. In the optimal conditions, Roundleaf Thorowax can bloom and develop robust foliage from late spring to mid-autumn.


Roundleaf Thorowax (Bupleurum rotundifolium) is a hardy, drought tolerant perennial with attractive foliage and long-lasting blooms. It can be pruned to create a low, neat hedge or a mid-height flowering background shrub. Pruning is best done in early spring before new growth begins or in the middle of summer after blooms fade. Cut any dead or dying stems back to the soil line, near the base of the plant. You can then clip off unwanted straggly branches or overgrown stems to maintain the desired shape or size. If you want to reduce the overall size, you can cut back all stems leaving about 4”-6” of growth.