Thalictrum flavum ssp. glaucum
yellow meadow rue
Southern Europe, North Africa, and Turkey
Overview
Thalictrum flavum ssp. glaucum spp. is the yellow-flowered meadow rue, growing 48–72 inches (120–180 cm) tall and 24–36 inches (60–90 cm) wide. The subspecies name 'glaucum' means 'blue-gray', describing the powdery blue-gray finely divided columbine-like foliage that is the plant's primary ornamental feature. The blue-gray leaf colour is created by a waxy glaucous bloom on the leaf surface, holding the cool tone from spring emergence through fall. Bright lemon-yellow fluffy stamen-only flowers in dense terminal clusters appear in June and July — a yellow flower colour rare in Thalictrum spp., which more typically blooms in lavender or purple. The blue-gray foliage paired with yellow flowers gives a colour combination not available elsewhere in the genus. The 4–6 foot stature places this at the back of borders and requires staking on exposed sites. More sun-tolerant than other meadow rues but still requires consistent moisture. Mildly toxic. Deer avoid the foliage.
Native Range
Thalictrum flavum ssp. glaucum spp. is native to southern Europe, North Africa, and Turkey.Suggested Uses
Used at the back of borders as a tall vertical accent. The blue-gray foliage carries colour interest from spring through fall, even outside the bloom period. The yellow-on-blue-gray colour combination pairs well with purple- and pink-flowered companions.How to Identify
Appearance
Size & Dimensions
Height4' - 6'
Width/Spread2' - 3'
Reaches mature size in approximately 3 years
Bloom Information
Flowering in June and July, approximately 4 weeks. Bright lemon-yellow fluffy stamen clusters.
Detailed Descriptions
Flower Description
Bright lemon-yellow, fluffy, in dense terminal clusters — stamen-onlyFoliage Description
Powdery blue-gray, finely divided, columbine-like, glaucousGrowing Conditions
Sun Requirements
Requires 5-8 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
Care & Maintenance
Care Guide
Plant in full sun to partial shade. Moist, humus-rich soil. Stake the tall stems. More sun-tolerant than other meadow rues. Mildly toxic.Pruning
Cut back flower stems after bloom. Cut to ground after frost.Pruning Schedule
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fall