Photinia – deried from the Greek word photeinos meaning “shining,” in reference to the shiny leaves of some species

Native range: SE Asia

Leaves:

• Alternate
• typically simple
• lanceolate with a short petiole
• margin usually serrate
• bright red new foliage (lasts through season), fade to a deep glossy green in 2-4 weeks
• continual trimming of the ends of the shoots stimulates the plant to keep producing new leaves throughout the year

Flowers:

• inflorescence:
  • small, white flowers in umbellate clusters
  • 10- 12 cm wide
• 5 sepals, fused at base
• 5 petals
• many stamens
• 2 styles (rarely 3-5)
• unpleasant odor attracts flies as pollinators

Fruit:

• pome
• red
• autumn, persists through winter

Other characteristics:

• trees to 45 ft. and shrubs
• deciduous or evergreen

Relevant info:

• fast-growing, tolerant of poor conditions, but subject to leaf blights
• in SE U.S., where high humidity and moist conditions are prevalent, fungal leaf spot, Entomosporium maculatum, has been lethal to many hedges
• two species sometimes grown, but most in the landscape are a hybrid of the species, P. X fraseri
  • hybrid name recognizes the Fraser Nursery in Birmingham, Alabama, where the hybrid originated in 1940
  • cross of Chinese P. serrulata (seed parent) and Japanese P. glabra

Ecology & Adaptations:

• native mostly to warm temperate Asia, from the Himalayas east to Japan and south to India and Thailand
• shade tolerant:
  • evergreen leaves photosynthesize throughout the year, absorbing winter light when leaves are not present on deciduous trees in the over-story
  • concentration of photosynthetic pigments
  • increases in leaves in low light
  • in lower light, CO2 levels are increased via gas exchange through open stomates
  • light saturation point is lower and CO2 assimilation rate is higher in shaded conditions
  • longer petioles (leaf stems) in older leaves permits spacing of leaves that maximizes light capture
• pollination – unpleasant odor of flowers attracts dipteran pollinators (flies)
• drought tolerant:
  • increased anthocyanin (water-soluble red-purple pigment) concentration aids water regulation in younger leaves
  • thicker older leaves retain water
  • stomata closure limits water loss (but also decreased photosynthesis)
  • in full sun, photosynthesis decreases during mid- day, which limits water loss when light is most intense
  • proline concentrations, which help prevent water loss, increase under drought conditions and salt exposure (in agricultural landscapes)
• cold resistant – leaves are resistant to cold, presumably because the solute concentration in cells decreases freezing temperature and prevents waters from leaving cells and contributing to extracellular ice crystals in freezing temps