Philadelphus karwinskyanus Koehne, Hydrangeaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 7 (Go to the risk assessment)

Common name(s): [more details]

English: evergreen mock orange, philadelphus, syringa

Habit:  shrub

Description: 

Genus: "About 65 species of shrubs, mostly erect but with curving or drooping branches; leaves opposite, simple, commonly deciduous, flowers white, often fragrant and showy, solitary or in small clusters or racemes, calyx tube united to ovary, sepals and petals usually 4, stamens many, ovary inferior or half-inferior, styles usually 4; fruit a capsule, seeds many."

Species:  "Evergreen, somewhat scandent shrub, to 12 ft.; leaves ovate, to 3 in. long, 5-nerved, sparsely hairy, flowers about 1 in. across, in 5-30-flowered panicles, calyx, hairy  (Bailey & Bailey, 1976; pp. 854-855).

"Evergreen shrub, to 4 m high in its habitat, slightly climbing, shoots long and nodding, the flowering shoots over 50 cm long, abundantly branched; leaves ovate, 4-7.5 cm long, 2-3.5 cm wide, long acuminate, base round and 5 veined, with 5-8 sharp, widely spaced teeth on either edge, both sides sparsely strigose-wooly; corolla 2.5-3 cm wide, petals obovate-rounded, glabrous on the inside, exterior somewhat pubescent on the midline, pure white, faintly scented, stamens about 45"  (Krüssmann, 1977; vol. 2, p. 381).

Habitat/ecology:  Open moist and wet areas from 3000-5000 ft. elevation (Hawaii's Most Invasive Horticultural Plants).

Propagation:  Seed and vegetatively. The stems of this species root where they touch the ground, and one shrub soon gives rise to a thicket capable of covering trees or hillsides (Hawaii's Most Invasive Horticultural Plants).

Native range:  Mexico.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (pp. 38-39) Vouchers cited: D. Lorence et al. 5811 (PTBG, US), T. Flynn 519 (PTBG), R. Howard 20217 (A, PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (pp. 38-39) Voucher cited: K. M. Nagata 2461 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Martz, Kim/Loope, Lloyd L. (2002) (p. 20) East Maui. Voucher cited: Starr & Martz 980129-1 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced cultivated	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 38)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Philadelphus karwinskyanus, please let us know.