Tree peony.  Yellow.  Mild fragrance.  Mid.  USDA zone 2a and warmer.  

7 favorite votes.  

Hybrid / Species crosses.  Dark red.  Wine-red.  Semi-double to double, Japanese (anemone, imperial) bloom form.  Mid.  USDA zone 2a and warmer.  Height of up to 30" (up to 75 cm).   William Henry Krekler (1977).

7 favorite votes.  

Hybrid Lutea, Tree peony.  Pink, yellow undertones, deep pink veining, purple flares.  Moderate fragrance.  Single, ruffled bloom form.  Mid.  USDA zone 2a and warmer.  Height of up to 5' (up to 150 cm).   Prof. Arthur Percy Saunders (1948).

7 favorite votes.  

Hybrid lactiflora.  Red, purple shading.  Very double, crown bloom form.  Early.   Unknown Chinese Breeder(s).

7 favorite votes.  

Hybrid lactiflora.   Kelway (and Son).

7 favorite votes.  

Hybrid / Species crosses.  Red.  Yellow anthers, red stamens.  None to mild fragrance.  Single bloom form.  Early.  Height of up to 32" (up to 80 cm).   Lyman D. Glasscock (1931).

7 favorite votes.  

Hybrid lactiflora.   Peter Barr.

7 favorite votes.  

Tree peony.  Pink.  Mild fragrance.  Mid.  USDA zone 2a and warmer.  

7 favorite votes.  

Hybrid suffruticosa, Tree peony.  Pink.  Cherry-pink.  Large, double, ruffled bloom form.  USDA zone 2a and warmer.   Unknown Japanese Breeder(s) (1931).

7 favorite votes.  

Hybrid lactiflora.  Pink, deep pink undertones.  Mild, sweet fragrance.  Double bloom form.  Late.  Height of up to 35" (up to 90 cm).   Don Hollingsworth (1973).

7 favorite votes.  

Hybrid / Species crosses.  Rose-pink, yellow center.  Small, single, cupped bloom form.  Very early.  Height of up to 14" (up to 35 cm).   William Henry Krekler (1985).

7 favorite votes.  

Hybrid lactiflora.   Edward Auten, Jr. (1933).

7 favorite votes.  

Hybrid suffruticosa.  Violet-red, fuchsia / magenta shading.  Large, full bloom form.   Joseph Pernet-Ducher (1885).

7 favorite votes.  

Hybrid / Species crosses.  White.  Small to medium, single bloom form.  Late.  USDA zone 2a and warmer.  Height of up to 47" (up to 120 cm).   Prof. Arthur Percy Saunders (1947).

7 favorite votes.  

Hybrid lactiflora.  Light pink, light yellow undertones.  Moderate fragrance.  Double bloom form.  Late.  Height of up to 2' (up to 60 cm).   Unknown New Zealand Breeder(s).

6 favorite votes.  

Hybrid lactiflora.  Red.  Height of up to 42" (up to 105 cm).   William Henry Krekler (1979).

6 favorite votes.  

Hybrid lactiflora.  White.  Large, double, bomb bloom form.  Midseason.   Col. Jesse C. Nicholls (1954).

6 favorite votes.  

Hybrid suffruticosa.  Light pink, purple flares, ages to white .  Large, double, bomb bloom form.  Midseason.   Unknown Chinese Breeder(s).

6 favorite votes.  

Intersectional Hybrid / Itoh.  White, lavender flares.  None to mild fragrance.  Semi-double bloom form.  Midseason.  USDA zone 2a and warmer.  Height of up to 2' (up to 60 cm).   Roger Anderson (1984).

6 favorite votes.  

Hybrid lactiflora.   Julian L. Janus.

6 favorite votes.  

Hybrid rockii.  Deep pink, mauve shading, cream center, purple flares.  Mild fragrance.  Medium to large, single to semi-double, lotus bloom form.  Early-to-mid.   Chen Dezhong (1994).

6 favorite votes.  

Hybrid suffruticosa, Tree peony.  Pink, darker center, lighter edges.  Very large, double bloom form.  Midseason.   Michel Rivière (1992).

6 favorite votes.  

Hybrid lactiflora.  Light pink, yellow center, ages to white .  Strong fragrance.  Large, semi-double bloom form.  Early-to-mid.  USDA zone 6b through 9b (default).  Width of 4' (120 cm). J.R. Mann (1936), Julius J. Van Steen (1936).

6 favorite votes.  

Herbaceous species, Species.  Red.  Single bloom form.  USDA zone 2a and warmer.  

6 favorite votes.