Scarlet Firethorn

(Rosaceae - Rose Family)

FEATURES

• Form
  • medium-sized to large-sized ornamental shrub
  • species form matures at about 15' tall by 15' wide, but cultivars are usually smaller, and most shrubs are frequently pruned to smaller dimensions anyway
  • upright oval growth habit in youth, becoming open, straggly, and spreading with age
  • medium growth rate (rapid growth rate if pruned back hard)

• Culture
  • full sun to partial shade
  • prefers moist, well-drained soils in full sun, but is very urban tolerant and adaptable to poor soils, compacted soils, soils of various pH, heat, drought, and heavy pruning
  • propagated by seeds or rooted stem cuttings
  • Rose Family, with a number of minor disease and pest problems, but the two major diseases are scab (primarily affecting the fruits, but also the flowers, foliage, and stems in severe cases) and fireblight (affecting the newly emergent leaves and stems)
  • commonly available in container form, and sometimes staked or espaliered directly in the pot
  • in moderate to severe zone 5 Winters, the bronzed broadleaf evergreen foliage will severely "burn" or die, and stem dieback may occur anywhere from tip dieback all the way to the snowline
  • best time to prune vigorously growing specimens or espaliers is either right after bloom (to set up flower buds and fruits for the following year) or in Autumn or early Spring (to gain firm control with heavy pruning, and forego flowering and fruiting for an entire year)

• Foliage
  • dark green, broadleaf evergreen to semi-evergreen, and becoming unattractively bronzed in Winter, sometimes "burning" in exposed areas and turning dead-brown
  • densely alternate (clustered on the short spur shoots), lanceolate to narrow elliptical, and lightly serrated

• Flowers
  • white, somewhat malodorous, in late May to early June, as flat-topped to slightly curving 2" to 3" diameter inflorescences, derived from floral buds on the previous year's spur shoots

• Fruits
  • orange, orange-red, or yellow, depending upon cultivar
  • heaviest ornamental fruiting occurs on unpruned shrubs of scab-resistant cultivars sited in full sun, and can be quite outstanding in early Autumn when contrasted against the dark green foliage
  • maturing in September as pendulous clusters from the numerous spur shoots, and usually persistent only into late Autumn, before abscission or being eaten by wildlife

• Twigs
  • pubescent purple-green when emergent, changing to brown but often obscured by the dense foliage
  • spines often terminate the spur shoots, with the spines also obscured by the dense foliage
  • upper vertical stems assume the appearance of co-dominant pyramidal spires, whether unpruned or when topped every one to two years

• Trunk
  • multitrunked, brown, and somewhat rough, but seldom noticed due to the low branching and evergreen foliage

• ID Summary
  • pyramidal spires of upper branches occur on this shrub that quickly spreads with age, having broadleaf evergreen foliage that is an unnattractive bronze in Winter, with copious white malodorous inflorescences in late Spring that give rise to the characteristic orange clusters of fruits in early Autumn, which are often tainted with severe black scab even on many modern-day compact cultivars

• Function
  • formal or informal thorny barrier hedge, visual screen, specimen, or wall espalier; often incorrectly used as a foundation shrub (where it gets far too large except for the most compact cultivars)

• Texture
  • medium texture
  • thick density

• Assets
  • showy Autumn true-orange fruits (some forms are red-orange or yellow-orange)
  • showy late Spring white inflorescences
  • broadleaf evergreen foliage
  • dense spiny growth serves as a bird refuge and as a barrier to traffic

• Liabilities
  • many old and new cultivars are prone to foliage fireblight (stem/foliage termini die in Spring and Summer) and fruit scab (fruits become blackened before they fully mature), both of which are terribly unsightly from a cosmetic perspective
  • inflorescences are somewhat malodorous
  • spines are sharp and mostly hidden by the foliage
  • unnattractive bronzed foliage may "burn" or die in severe Winters
  • fruits are not persistent into Winter
  • most forms get far too large and spreading for the site in which they are located, and require frequent pruning to keep them in-bounds (which reduces flowering and fruiting the following year)

• Habitat
  • zones 5 (or 6) to 9
  • native to Southern Europe

• Alternates
  • barrier shrubs/hedges with spines/thorns/prickles (Acanthopanax sieboldianus, Berberis koreana, Berberis x mentorensis, Berberis thunbergii, Rosa 'F.J. Grootendorst', etc.)
  • shrubs with ornamental Autumn and Winter fruits (Aronia arbutifolia, Ilex verticillata, Myrica pensylvanica, Rosa rugosa, etc.)

• Variants
  • although many cultivars and a few species exist, primarily noted for their disease resistance, fruit color, relatively compact habit, and/or cold hardiness, most are still moderately to severely susceptible to fruit scab and foliage/stem fireblight; the most common in the nursery trade are:
  • Pyracantha angustifolia 'Yukon Belle' - to 7' tall and wide, with orange fruits, probably the most hardy orange-berried form, but susceptible to scab and fireblight
  • Pyracantha coccinea 'Kasan' - to 8' tall and wide, with red-orange berries, but susceptible to scab
  • Pyracantha x 'Gnome' - to 7' tall and wide, with orange berries, but susceptible to scab
  • Pyracantha x 'Gold Rush' - to 10' tall and wide, with orange-yellow fruits, resistant to scab, but only cold hardy to zone 7
  • Pyracantha x 'Mohave' - to 10' tall and wide, with orange-red berries, being both scab and fireblight resistant
  • Pyracantha x 'Navaho' - similar to 'Mohave', but maturing at 6' tall by 8' wide

• Translation
  • Pyracantha translates as "fire thorn", referring to the reddish fruits and the sharp spines.
  • coccinea translates as "scarlet", again in reference to the fruits.

• Purpose
  • Scarlet Firethorn is an ornamental shrub often utilized as a spiny barrier hedge, screen, or specimen, clothed in white inflorescences in late Spring and capable of a vibrant orange fruit display in late Summer and early Autumn.

• Summary
  • Pyracantha coccinea is known as an urban-tolerant shrub with spiny branches, showy white malodorous late Spring inflorescences, broadleaf evergreen dense foliage, spire-like upper branches, and orange Autumn fruits.