Euphorbia characias ssp. wulfenii, Spurge

Upright, thick stems with pointed, blue-green foliage. In late spring through early summer, stems are topped with large, acid-green flower heads (the bracts are actually the showy bits). This tough perennial is evergreen in mild climates; semi-evergreen in colder. Clumper; seeds a bit but is not invasive. It does best with ok drainage; might flag a bit in hot summers with high humidity.  Mature size: 2-3 ft T x W moist to dry site Sun to pt shade  Minimum temperature: -5° F Whole plant photo by Emőke Dénes, CC BY-SA 4.0, via Wikimedia Commons Close up of flower clusters by Salix, CC BY-SA 4.0, via Wikimedia Commons Foliage only photo by James Steakley, CC BY-SA 3.0, via Wikimedia Commons