Euphorbia epithymoides ‘First Blush’ (syn. E. polychroma) – An herbaceous perennial with elongated light green leaves edged in cream that emerge with a rose-pink flush that often lasts into summer. It bears chrome yellow flower bracts in spring that fade to the foliar tones. Cushion Spurge thrives in part to full sun with well drained soil. Grows 12-18″ high by 18-24″ wide. Zone 4.
Ranunculus ficaria ‘Flore Pleno’ – A tuberous perennial that is often used as an ephemeral groundcover in part to full shade exposures with moist soils. It bears small double yellow flowers (with green centers as they open) from April to May. The glossy green leaves resemble Marsh Marigold and form a dense mat. Can prove to be invasive. Grows 2-4″ high by 12″+ wide. Zone 4.
Doronicum orientale ‘Little Leo’ (syn. D. caucasicum) – The bright yellow semi-double daisy blooms of this herbaceous perennial are particularly welcome in early spring, when the blue Forget-Me-Nots are also vying for attention. This is a compact form with deep green, serrated heart-shaped foliage. Best grown in part shade. Grows 10-14″ high by 10-12″ wide. Zone 4.
Dicentra scandens (renamed Dactylicaphos scandens) – Climbing Yellow Bleeding Heart is a native of the Himalayas and it can be a bit difficult to establish. It bears mid yellow heart-shaped flowers (in clusters) all summer over ferny green foliage. It seems to prefer morning sun or filtered shade and the tuberous roots should be mulched for winter. Grows 4-6’+ high by 3′ wide. Z6.
Inula magnifica (syn. Inula afghanica) – A tall stately perennial that works well at the back of the mixed border – it bears bright yellow daisies (about 3-4″ wide with strap-like petals) in late summer with the blooms well above the coarse green hairy foliage. Pair this perennial with grasses such as Miscanthus ‘Gold Bar’ or Pennisetum ‘Foxtrot’. Grows 5-6′ high by 3′ wide. Zone 5.