This grower is fairly sure of this plant identification.
Euphorbia characias var. characias (Spurge). Bears clusters of narrow, greyish-green leaves. In spring and early summer, dense spikes of pale yellow-green flowers with dark purple centres are borne.
They are hardy and evergreen. Watch out; they are poisonous and allergenic.
Border, hedging, edging, Foliage, ornamental
Italics = data drawn from parent genus or speciesView Full Plant Finder Record