This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Shrubby or herbaceous plants with alternate simple pinnate or bi- or tri-ternate leaves, and free or sheathing stipules. Flowers rose or white, inflorescence variable. Sepals and petals 4 or 5. Stamens 20 to 60, inserted around the mouth of the calyx-tube. Carpels usually 5, dehiscent; seeds many, rarely few, oblong or narrow. The name is said to be derived from to wind, in allusion to the suitability of some species for forming garlands. Somewhere about fifty species occur in the temperate and cold regions of the North, a few reaching the mountains of the tropics. This name was applied to a plant by Theophrastus, supposed to be 8. salicifolia. The species cultivated are numerous, but we must confine our enumeration to a selection of the best. The plant often named 8. Japonica, or S. barbata, will be found under its proper genus Astilbe.
1. S. Ulmaria. Meadow Sweet. - This attains a height of 3 or 4 feet in moist places. Leaves 1 to 2 feet long, interruptedly pinnate, serrate, clothed with a white tomentum beneath. Flowers white, very fragrant, in large terminal cymes. Carpels twisted, glabrous. This is one of our handsomest native plants, of which there is a double-flowered variety worthy of cultivation in a large garden. It flowers in Summer.
Fig. 81. Spiraea Aruncus. (1/6 nat. size.)
2. S. Filipendula. Dropwort. - A tuberous-rooted plant 1 to 2 feet high. Leaves interruptedly pinnate, glabrous. Flowers cymose, white tinged with pink. Carpels straight, pubescent. The double variety of this is one of the best of the genus for a border. June and July.
3. S. Aruncus (fig. 81). Groat's Beard. - A tall vigorous plant about 4 feet high, with large tripinnate radical leaves and yellowish white dioecious flowers. A native of Central Europe and Siberia, flowering in Summer.
4. S. lobata. Queen of the Prairies. - In habit this closely resembles the Meadow Sweet. The large leaves are interruptedly pinnate with nearly glabrous palmately-divided leaflets, the terminal one largest. Flowers in large terminal corymbs, bright rosy-red. North America.
5. S. palmata. - A very beautiful species of recent introduction. An erect glabrous plant with palmately-lobed toothed leaves and large corymbose panicles of brilliant crimson flowers. The stems and leaf-stalks are of the same colour as the flowers, and altogether it forms one of the most striking and effective species in cultivation. A native of Japan.
6. S. bella. - A pretty species about 3 feet high, with simple ovate acute serrate glabrous leaves and terminal spreading cymes of rosy-red flowers. A native of Nepal, flowering in July.
7. S. Fortunei, syn. S. callosa of gardens. - From 4 to 6 feet high, with terminal flat corymbs of rosy-red flowers. Leaves glabrescent, simple, lanceolate, acute, sharply serrate, serratures thickened at the tip. A very handsome and desirable Chinese species.
8. S. grandifiora, syn. Exochorda grandifldra. - A glabrous shrub with oblong-lanceolate membranous petiolate leaves and large white flowers in axillary slender few-flowered racemes-This handsome species has much larger flowers than the others, the calyx is furnished with two bracts at its base, and the carpels are connate. It comes from the North of China, and flowers in May.
9. S. prunifolia. - The variety flore pleno is one of the most familiar in gardens. It is a dwarf shrub with small glabrous lanceolate leaves connate at the base and irregularly serrated on the upper half, and pure white flowers produced in fascicles the whole length of the branches. A Japanese species, flowering in Spring.
10. S. Reevesiana, syn. S, corymbosa, S. lanceolata, and S. Cantoniensis. - A glabrous shrub 3 or 4 feet high, with small simple lanceolate trilobate and deeply-toothed leaves. Flowers in terminal umbels,- white and showy, appearing in early Summer. There is also a good double-flowered variety. Japan. S. chamaedrifolia is an allied Japanese species with smaller flowers and crenately-lobed leaves.
11. S. Lindleyana. - A tall branching shrub with large unequally pinnate leaves and large terminal panicles of white flowers. Leaflets 11 to 21, sessile, ovate-lanceolate, coarsely serrated, glaucous beneath. A native of the Himalayas, flowering towards the end of September. S. sorbifolia is a closely-allied species or variety from India.
12. S. Douglasii. - An erect hand-some shrub with simple oblong-lanceolate obtuse leaves serrulate towards the apex, and clothed with a white down beneath. Flowers nearly sessile, in a dense terminal thyrsoid panicle from 6 to 9 inches in length. A native of North-western America.
13. S. Nobleana. - Near the last in habit and foliage, with a looser inflorescence. Leaves elliptical or oblong, obtuse or acute, more or less toothed, pubescent or nearly glabrous below. Flowers purplish red. Also from North-western America, and possibly a variety of the last. S. Menziesii and S. salicifolia are both very near the foregoing, and perhaps, botanically speaking, forms of one species, though they are distinct enough in the cultivated plants.