Verbena

Plant Characteristics

Cultivation

USDA Zones:		4

Scientific Names
Verbenaceae >	Verbena >

Verbena (Verbena or Vervain) is a genus of annual and perennial herbaceous or semi-woody flowering plants with about 250 species in the family Verbenaceae. The majority of the species are native to the New World from Canada south to southern Chile, but some are also native in the Old World, mainly in Europe including V. officinalis, V. supina.

The leaves are usually opposite, simple, and in many species hairy, often densely so. The flowers are small, white, pink, purple or blue, with five petals, and borne in dense spikes.

Read about Verbena in the Standard Cyclopedia of Horticulture
Verbena (ancient Latin name of the common European vervain, V. officinalis). Verbenaceae. Annual or perennial herbs or subshrubs, which are diffuse or sometimes creeping, some of them common flower-garden plants and sometimes grown in the greenhouse. Leaves opposite or rarely ternately whorled or alternate, dentate or usually incised or dissected, rarely entire: spikes terminal, sometimes densely imbricated, sometimes elongated, slender and remotely fld., sometimes broadly corymbose or paniculate on an erect st., rarely axillary: fls. small or medium-sized, sessile; calyx tubular, 5-ribbed, 5-toothed; corolla-tube straight or incurved, limb spreading, somewhat 2-lipped, lobes 5, oblong or broad, obtuse or retuse; stamens 4, in pairs; ovary entire or very shortly 4-lobed at apex, 4-celled, cells 1-ovuled: fr. separating into 4 narrow pyrenes or nutlets.—About 80-100 species, chiefly natives in Trop. and extra-Trop. Amer. Some of them are unshowy weedy plants in fields and waste grounds in the U. S. and Canada. For the lemon verbena (V. citriodora), see Lippia citriodora. Verbenas rank high among plants grown as garden annuals. Their clusters of showy and often fragrant flowers are borne in constant succession from June till frost. They vary from white through lilac and rose to purple and dark purplish blue, with shades of pink and pale yellow. The clusters are about 2 inches across and contain a dozen or more flowers each 5/8 to 7/8 inch across. The plants are grown with ease in any usual garden soil and condition. For general purposes, the plants should be grown from seeds. The plants are set about 1 foot apart each way, although a strong plant in good soil may spread 3 feet or so in the course of the season. Usually the seeds are started indoors, but if sown in the open as soon as the season is settled and warm, flowering plants should be secured in July or early in August. The verbena of gardens is a semitrailer, the flower-stems not rising more than about a foot or so. It is sometimes used as a ground-cover under gladioli, lilies, and other tall plants, and in the margins of shrubbery plantations. It also makes an excellent window-box subject. When special colors or named varieties are desired it is necessary to propagate verbenas by cuttings. To propagate a particularly choice variety by cuttings, shorten back the plants about September 1, keep them well watered, and by the end of the month there will be plenty of quick tender growth suitable for cutting. Put the cuttings in the propagating-house or even in flats with soil in bottom and sand on surface. Place the flats in a coldframe, and keep them moist and shaded until the cuttings are rooted. When rooted, transfer to flats in a cool light house until after New Year's. Then pot them, using 2 1/2-inch pots, and allow a temperature of 50° F., which will soon give plenty of material for additional cuttings. Verbenas increased from cuttings tend to flower early, and those propagated in February or March will require at least one pinching. When planting-out in beds for summer bloom, bend the plant over nearly to the horizontal, so that the new growth will spread along the surface of the soil. These shoots will take root quickly, thereby covering the ground. The old method was to peg the plants down. In propagating general stock, sow the seed in February and pot into 2-inch pots as soon as the seedlings are up an inch. A temperature of 45° to 50° will answer, but they should have full light. There is no place equal to a mild hotbed for young verbenas. About April 15 plunge the pots in a few inches of soil in a mild hotbed. Lift them now and then and rub off the roots which go through the bottom of the pot, in order to check growth and hasten flowering. Customers want to see them in flower before buying, and most of them wait till the end of May. However, verbenas may be planted out early in May, as a slight frost will not injure them. The evolution of the garden verbenas has taken place in about seventy-five years. Although the history can be made out with considerable clearness, yet the botanical origin of the present florist's race, as to the species involved and the extent to which they have contributed, is not satisfactorily recorded. It is probable that four species have been more or less fused in the race or group known as Verbena hybrida,—V. chamaedryfolia, V. phlogiflora, V. incisa, and V. teucrioides. These species are shown in Fig. 3910. For an historical account of the development of the garden verbenas, see Cowen, "Cyclopedia of American Horticulture," Vol. IV. It is impossible satisfactorily to classify the hybrid garden verbenas according to their botanical derivation. They are conveniently classed according to color of flowers into: (1) Selfs, or one-colored varieties; (2) Oculatas, or eyed varieties; and (3) Italians, or striped varieties. As to habit they may be divided into: (1) Standards, those of the ordinary loose, spreading growth; and (2) Compactas, which are much reduced in stature and of more condensed form. Verbenas now in cultivation are shown in Figs. 3910. 3911. Latin trade names probably mostly or entirely belong with the garden or hybrid race of verbenas, such as compacta, coccinea, grandiflora, monstrosa, caerulea, candidissima, italica, auriculaeflora, striata. V. radicans is listed as an alpine species of trailing habit and with crimson fls., suitable for rock-gardens. The V. radicans of botanists (Gill & Hook.) is an Andean species with procumbent rooting sts., glabrous divided lvs. with ultimate segms. very narrow, and lilac-colored fragrant fls. in short head-like spikes. The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.

Cultivation

A very easily grown plant, it succeeds in any moderately fertile well-drained but moisture retentive soil in a sunny position¹ ^RH. Plants are very tolerant of neglect and will maintain themselves for a number of years even when growing in dense weed competition^k. Self-sows freely when growing in a suitable position^k. The growing plant attracts butterflies and moths³⁰.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires moist soil. The plant can tolerates strong winds but not maritime exposure^pf.

Propagation

Seed - sow early spring in a greenhouse and only just cover the seed^pf. Germination should take place within 3 weeks. Prick out the seedlings into individual pots once they are large enough to handle and plant them out in early summer. If you have sufficient seed, it can also be sown in situ in late spring. Division in spring. Larger divisions can be planted out direct into their permanent positions. We have found that it is best to pot up smaller divisions and grow them on in light shade in a greenhouse or cold frame until they are growing away well. Plant them out in the summer or the following spring. Basal cuttings in early summer. Harvest the shoots with plenty of underground stem when they are about 8 - 10cm above the ground. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer^pf.