Euphorbia x martinii ‘Rudolph’ – The dark green foliage of this evergreen spurge reaches heights of 16-24″, depending on soil conditions. The growth tips turn a deep red in late fall and stay that way through winter (hence the red nose reference), and are followed by spring to early summer chartreuse blooms with their own tiny red eyes. Part to full sun. Zone 6 hardy.
Euphorbia characias ‘Glacier Blue’ – A beautifully variegated form with evergreen foliage of greyish-blue, edged in cream – a great companion for blue fescue or blue oat grass (Helictotrichon). The spring display of cream flowers with variegated bracts is equally attractive and this 18″ tall cultivar is much hardier than its gold variegated counterpart, ‘Tasmanian Tiger’. Part to full sun. Zone 7 hardy.
Euphorbia griffithii ‘Fireglow’ – You need a bit more room (as it tends to spread) and lean soil (to keep it from flopping) to grow this variety, but it’s definitely worth it. The intense orange bracts appear in early summer on 3′ tall stems of light green foliage. ‘Fireglow’ is one of the hardier Euphorbias, although it is not evergreen. Part to full sun. Zone 4 hardy.
Euphorbia amygdaloides ‘Purpurea’ (syn. ‘Rubra’) – A mounding, evergreen form with rich reddish-purple foliage contrasted by lime green spring blooms. Purple wood spurge is often recommended for shade gardens, although I find it does best with some morning or late afternoon sun. It is a great companion plant for gold-leaved Heuchera or Carex ‘Evergold’. Zone 5 hardy.
Euphorbia characias subsp. wulfenii – A tall structural perennial with bold 3-4′ tall stems of bluish-green foliage. Use this evergreen Euphorbia in the center of the island bed or back of the border where the large chartreuse blooms can really stand out. It is best planted in full sun with well-drained soil. Wulfenii looks great when paired with the equally drought tolerant evergreen shrub Ceanothus ‘Victoria’. Zone 7 hardy.