Philadelphus lewisii
Credits
Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Philadelphus lewisii' from the website Trees and Shrubs Online (treesandshrubsonline.
Synonyms
- Philadelphus lewisii var. parvifolius Torr.
- Philadelphus lewisii var. californicus (Benth.) A.Gray
- Philadelphus lewisii subsp californicus (Benth.) Munz
- Philadelphus californicus Benth.
- Philadelphus billiardii Koehne
Other taxa in genus
- Philadelphus coronarius
- Philadelphus delavayi
- Philadelphus × falconeri
- Philadelphus hirsutus
- Philadelphus incanus
- Philadelphus inodorus
- Philadelphus mexicanus
- Philadelphus microphyllus
- Philadelphus pekinensis
- Philadelphus pubescens
- Philadelphus purpurascens
- Philadelphus satsumi
- Philadelphus schrenkii
- Philadelphus sericanthus
- Philadelphus subcanus
- Philadelphus: The Hybrids
- Philadelphus tomentosus
Editorial Note
In the broad interpretation adopted by the Flora of North America (2025), which we follow, this extremely variable species includes plants in cultivation as Philadelphus insignis, P. californicus and P. cordifolius (the first two of which were discussed by Bean under those names).
Bean noted the distinction between P. lewisii and P. californicus as being the latter’s exposed axillary buds (not hidden by the petioles), but the diagnostic value of this character appears questionable, perhaps merely ‘an expression of extra-vigorous growth’ (Flora of North America 2025). There is at present little evidence to justify segregating these species, though the situation may alter as more research is undertaken.
Nomenclature aside, Bean’s observations on the varied material in cultivation under the different names are of significant horticultural value, so we reproduce below his entries under their original headings, pending a fuller, revised treatment to be provided when funding is available. If you would like to sponsor the account of this genus please write to editor@treesandshrubsonline.org
Philadelphus californicus
An elegant, pendulous-branched shrub up to 10 ft high, the young shoots glabrous, the year-old bark peeling. Leaves three-nerved, ovate, 11⁄2 to 3 in. long, 3⁄4 to 2 in. wide, shortly and broadly toothed, or nearly entire (especially on the flowering twigs), either glabrous or slightly downy beneath. Flowers 1 in. or less wide, pure white, slightly fragrant, produced numerously in panicles at the end of the shoot, often over twenty flowers in each. Petals oblong-obovate; calyx glabrous outside the lobes, downy on the margins, and near the apex inside; styles united, stigmas separated. Native of California. One of the most distinct of American species. On weak shoots its inflorescence may be only a simple raceme, but normally it is composed of several racemes, thus forming a true panicle. Flowers small and crowded.
Philadelphus lewisii
A shrub up to 12 ft high, of graceful, pendulous habit; year-old branches with greyish-brown, non-peeling bark. Leaves broadly ovate to ovate-lanceolate, 11⁄2 to 4 in. long, 1 to 21⁄2 in. wide, coarsely and distinctly toothed or, especially on the flowering twigs, entire, with scattered hairs beneath, still fewer above. Flowers five to nine, in racemes, scentless, white, 11⁄3 in. across; petals oval; calyx smooth outside like the flower-stalk, downy at the margins, and near the apex of the lobes inside; styles divided half-way down. Native of western N. America from British Columbia to Oregon; introduced about 1823. It is one of the most elegant and floriferous of all the taller species.
Philadelphus lewisii var. gordonianus
Leaves downy beneath all over the blade. Flowers (at least in Lindley’s type) up to almost 2 in. across. British Columbia to California. A handsome and very hardy variety, introduced by David Douglas in 1825, and described (as a species) from a plant raised from the seeds he sent. P. lewisii is a variable species. The var. gordonianus and others recognised by Dr Hu, intergrade with each other and with the type. The plant described above under P. lewisii does not perfectly match the type of P. lewisii, but neither does it fit into any of the named varieties. The species seems to vary in the fragrance of its flowers.
Philadelphus insignis
The origin of this handsome mock orange is not known, but it is probably a hybrid. It is a vigorous bush up to 10 or 12 ft high; young shoots glabrous or nearly so; bark of year-old ones not peeling. Leaves ovate or sometimes heart-shaped, 11⁄2 to 31⁄2 in. long, 11⁄4 to 21⁄2 in. wide, minutely and sparsely toothed, glabrous and glossy green above, shaggy with pale hairs beneath. Flowers faintly perfumed, pure white, cupped, a little over 1 in. across, produced during late June in leafy terminal panicles of fifteen to over twenty blossoms. Petals roundish, 3⁄4 in. long, overlapping; calyx and flower-stalk hairy; style shorter than the stamens, united just below the stigmas. Although cultivated since before 1870, this is not much grown in gardens, although certainly one of the most attractive of mock oranges. It is distinct in its many-flowered inflorescences, combined with its glossy green leaves, its cupped flowers, and overlapping petals, and is useful in flowering well into July. Rehder considered that P. insignis is a hybrid between P. pubescens and either P. californicus or P. cordifolius (an ally of P. californicus not treated here). Dr Hu, however, points out that matching plants occur wild in California and accepts P. insignis as a Californian native, allied to P. californicus (Journ. Arn. Arb., Vol. 37, p. 40). [Bean included Philaldelphus ‘Souvenir de Billiard’ as a synonym for P. insignis.]
