Thalictrum sphaerostachyum - Meadow-rue

Thalictrum sphaerostachyum is a bushy meadow-rue that closely resembles Thalictrum flavum ssp glaucum, but surpasses it with its luxuriant growth, the beauty of its foliage with a truly blue hue, and the generous flowering of a soft lemon yellow. Its beautifully rounded and fluffy inflorescences appear in summer, carried by tall and sturdy stems. This tall perennial thrives at the back of partially shaded borders, in fertile and moist soil.

Thalictrum sphaerostachyum belongs to the buttercup family. It is a rare species in cultivation, with uncertain origins, possibly related to the native Thalictrum flavum from Spain and North Africa. It is a deciduous herbaceous plant, perennial from its stump, with its vegetation emerging from the ground every spring and drying up in autumn. With a bushy habit, it eventually forms a clump about 1.50 m (5ft) tall and approximately 50 cm (20in) wide. Flowering occurs between June and August, consisting of tall and sturdy stems of grey-blue colour, topped with countless small flowers adorned with very long stamens. They are light lemon yellow and somewhat resemble mimosa. This flowering attracts bees and pollinating insects. The cut foliage, composed of small grey-green-blue leaflets, creates a beautiful association with the flowering.

Despite its elegance and rarity, the round-headed meadow-rue is highly hardy, to -20°C (-4°F), and requires no maintenance, although it may take some time to establish itself. It is the ideal plant to brighten up partially shaded to sunny areas of the garden. It looks stunning alongside a blue baptisia, a silver candle with purple foliage, daylilies, or Clematis recta 'Purpurea', for example. It can also be planted at the edge of shrub borders. Both the foliage and the flowers can be used in floral arrangements.