In common usage herb refers to plants with culinary, medicinal or similar uses.
|Standard Cyclopedia of Horticulture|
Herb, Herbs. An herb is a plant that dies to the ground each year, or at least that does not become woody. It may be annual, as bean, pigweed; biennial, as mullein, parsnip; perennial, as dictamnus, rhubarb; many of the perennials live only three or four years effectively. To the gardener, however, the word "herb" is ordinarily synonymous with herbaceous perennial: and he usually has in mind those particular perennial herbs grown for ornament, and which remain where they are planted. Goldenrod, bleeding-heart, sweet wilham, hollyhock, daffodil are examples. To many persons, however, the word herb is synonymous with sweet herb, and it suggests sage and tansy.
Herbs are grown in an herbary, which, as here understood, is a garden or collection of herbs, and particularly of perennial herbs, since the collection may then be more readily and certainly continued.
Herbs have two kinds of values,—their intrinsic merits as individual plants, and their value in the composition or the mass. It is usually possible to secure both these values at one and the same time. In fact, the individual beauty of herbs is enhanced rather than diminished by exercising proper care in placing them. Planted with other things, they have a background, and the beauties are brought out the stronger by contrast and comparison. It is quite as important therefore, to consider the place for planting as to choose the particular kinds of plants. The appreciation of artistic effects in plants is a mark of highly developed sensibilities. Happily, this appreciation is rapidly growing; and this fact contributes to the increasing popularity of landscape gardening and ornamental gardening. Some of the best effects in herb-planting are to be seen in the wild, particularly along fences, roads and streams. The planter must remember that herbs are likely to grow larger and more bushy in cultivation than in the wild.
A strip or border along the side of a lawn, or bounding an area, is the best place for a collection of herbs— whether annual or perennial—that are grown for ornamental effect. (See Fig. 597, Vol. I.) About any place there will be special uses of herbs. (See the plans, Figs. 1812, 1813.) The home-maker should cover the bare and unseemly places about the borders of his place (Fig. 1814). He may utilize a rock or a wall as a background (Fig. 1815). He may hide the ground-line out a post (Fig. 1816) or along a fence. Some of the commonest herbs, that excite the least admiration, are handsome when well grown and well placed. (See Fig. 1817.) One should always plant where the herbs will have relation to something else,—to the general design or handling of the place. This will usually be about the boundaries. The hardy border is the unit in most planting of herbs. (See Figs. 1814, 1818.) A rockwork herb border (Fig. 1819) is often useful in the rear or at one side of the premises. It is well to fill some of the corners by the house (Fig. 1820). In remote parts of the grounds, half-wild effects may be allowed, as in Fig. 1821. A pond or pool, even if stagnant, often may be utilized to advantage (Fig. 1822). A good herb out of place may be worse than a poor herb in place. But when herbs are grown for their individual effects, give plenty of room and good care (Figs. 1823, 1824). Other discussions of herbs in relation to planting will be found under Annuals, Biennials, Border, Landscape Gardening; also, for special uses, Alpine Plants, Autumn- Gardening, Kitchen-Garden and Flower-Garden, Spring- Gardening, Wild-Gardening, and others. L. H. B.
Herbaceous perennials in landscape planting.
No clear definition can be drawn between herbaceous perennials, biennials and annuals, between herbs and woody plants, for there are tender herbs that in a warmer climate would become shrubs or even trees, biennials that become perennials from stolons or offsets, and annuals that become biennials from seed germinating late in the season. Strictly speaking, however, herbaceous perennials are plants having perennial roots with tops that die to the ground annually, such as the columbines, larkspurs, day lilies, peonies, and most sedges, grasses and ferns. It is customary, however, in publications relating to this class of plants as well as in actual use, to include closely allied species with evergreen foliage, such as statice, yucca, sempervivums and certain pentstemons, together with plants having more or less woody and persistent above-ground stems, such as the suffruticose artemisias and the evergreen creeping species of phlox, veronica, vinca, the iberis, the helianthemums, and many alpine plants, while most bulbous-rooted plants which are true herbaceous perennials are separately classified and grown as bulbs.
Herbaceous perennials are an exceedingly important element of landscape, for they predominate in the mat of grassy or sedgy plants, covering dry or wet open fields, and in the surface vegetation under woods and shrubby thickets, either as a grass crop, composed of a comparatively few species cultivated for economic purposes, or as a wild growth made up of many species. The most attractive of these native plants are being cultivated and improved more and more from year to year for ornamental purposes, and are planted in the flower-garden, in artificial plantations of shrubbery and in the wild-garden. It is to such natives and to exotics of the same class, which are cultivated for a similar purpose, that reference is to be made hereafter.
Fifty years ago nearly every well-to-do family maintained a flower-garden, in which there were from fifty to one hundred and fifty species and varieties of herbaceous perennials, and there were few of the humbler families that did not have a dozen or more species established about their homes. Such plants were distributed by exchange among neighbors and were propagated and offered at retail by dealers, who, however, gradually allowed their stock of plants to run low or abandoned them altogether, until many kinds dropped out of cultivation or were neglected in favor of the tender "bedding out" plants that were brought suddenly into favor by the displays at the Philadelphia Centennial Exposition. Then they gradually declined in favor until the interest was newly revived at the period of the Chicago Exposition.
Since that time there has been such a constantly increasing interest in herbaceous perennials that there are now offered in catalogues of American nurserymen and collectors of native plants, nearly 3,000 species and varieties; exclusive of the many garden forms that are distinguished chiefly by the color of their flowers.
In use, the species and varieties of herbaceous perennials may be broadly separated into three groups.
First, plants for the garden requiring the favorable conditions of a highly cultivated ground, and careful attention to attain perfection and to persist and increase from year to year. This would include many exotics, some native species and most of the horticultural varieties. Many of such species wliich would find a congenial place only in the garden have attractive flowers which are so fugitive that they can be enjoyed only on the plant. Other species which are suitable to cut flowers from can hardly be grown in the flower-garden in sufficient quantity liberally to meet the floral requirements of the home, and they should be grown in quantity in the kitchen-garden or in a special cut-flower garden, for their crops of flowers. Included among plants of difficult cultivation with fugitive flowers are the rock or alpine plants, many of which are offered in European catalogues. (See article on Rock Gardens.)
Second, plants for the shrubbery, having aggressive habits, which make them rather objectionable in the flower-garden, but fit them to withstand successfully the crowding of shrubs. This class of plants will give variety and prolong the flowering season of shrub borders about lawns, and would be made up chiefly of strong- growing natives and a few of the more persistent exotics.
Third, plants for the wild garden, including the species that require for success some one of the many special conditions , prevailing in uncultivated or un- cultivable land, or which are so rampant as to require the restraint that some one of these natural conditions will provide. This class of plants would be made up chiefly of natives and a few of the more persistent exotics, and they would be used to enrich groups of native plants under woods, in meadows, along streams, ponds and hedge-rows and on poor soil. There are attractive plants that will and do grow successfully under all these conditions without special cultivation, and many of them may be already on the ground. If every plant in a group of natives is watched for at least a year, it will be found that many are so attractive at one season or another that they will be retained and developed in beauty by the gradual removal of the less desirable kinds, for which others that are more desirable may be substituted.
In arranging plants in new plantations, or in modifying existing plantations in gardens, lawns or woods, much more effective landscape compositions and more agreeable color effects can be secured by using large quantities of a few sorts than by using a few individuals of many kinds. Groups of different species should be chosen that will give from period to period during the flowering season effective and dominating masses of foliage and color, and all other plants of the garden which appear at the same time should be made subordinate to these.
Herbaceous perennials are propagated by divisions and from offsets, cuttings and seed. Some kinds, as dictamnus and papaver, may be propagated by root cuttings. The exotic species of gardens and many of the more readily grown natives can be obtained in wholesale quantities from nurserymen. A few exotics and a very large number of attractive native species can be procured in wholesale quantities from collectors of native plants, many of whom also offer nursery-grown plants of the best natives and of a few exotics. The attractive native plants in any region can be transplanted with little difficulty if they are collected with a good sod of earth about the roots. Warren H. Manning.
The culture of herbaceous perennials.
A good number of the herbaceous perennials grown in gardens are exceedingly easy of cultivation, thriving well in any moderately rich soil of suitable physical condition, and enduring winter cold and changeableness and summer heat and drought. There are, however, other species that do not grow well in the American climate, except in more moderate seasons or when placed where the climate is locally mollified. Whether the plants one desires to grow be easy or difficult of culture, one should aim first of all for a luxuriant growth, for any time or labor saved by poorly preparing the soil, or any money saved by the use of weak or stunted plants will be regretted later. Unless it is intended to imitate the effect of certain barrens in nature, a garden without luxuriance is lacking in essential quality.
The preparation of ground for planting consists, in the order of importance: in making the soil by openness and fineness suitable for root-penetration to a depth of 18 inches to 2 feet; in providing underground drainage at a depth of at least 2J/£ feet; in making the soil sufficently fertile; and in making the surface soil not liable to "baking."
Depth and physical condition of soil are very important, and should be one's first care. If the season is short and work must be rushed, it is better to omit the manuring and to devote all one's energy to securing a deep feeding-area for the roots and a fine physical condition of the soil. In the hardy border the roots are able to penetrate far more deeply into the soil than they do usually in a wild state or in ordinary field culture. This vigor of root-growth reaching to good depth, as compared with that of equal vigor but nearer the surface, gives not only greater endurance of drought but aids the plant to endure changeableness of weather, and particularly contributes to hardiness. Many plants are hardy only if protected until the roots are thoroughly established. This is more often noticed with trees and strong-rooted plants that are able to penetrate deeply into the subsoil, but the same applies to herbaceous plants, except that it is usually necessary to loosen the subsoil to ensure penetration by their finer roots to a satisfactory extent. It is not necessary to make the subsoil equal in richness to the upper part, but it should preferably be mixed with a portion of the surface soil.
The fine roots are the feeding roots and the surfaces of the soil-particles are their feeding-ground, so that in making the soil-particles smaller the feeding-surface is vastly increased, thus allowing for more roots and closer planting. A fine physical condition can usually be obtained by turning the soil over a few times. No soil should be turned or handled when too moist to crumble, as the clay in the soil is quick to become puddled, and therefore impervious to feeding-roots.
Underground drainage is necessary, since most plants cannot grow in soil filled with stagnant water. When the natural subsoil drainage is not sufficient, artificial means should be used. Unless the drainage is good, many plants will be injured in the rainier seasons or killed in winter. Plants that are not firmly established are often easily killed by excess of moisture about the roots during their dormant season; for example, many bog-plants otherwise perfectly hardy will winterkill if planted late in the fall. A further fact showing the effect of water on dormant roots is that many plants if cut down low enough in the fall to allow water, as from melting snow, to reach the root through the hollow stems, will often be entirely rotted by spring. Thus, when it is necessary to destroy goldenrod, the dry stems may be mown in late autumn with a sharp scythe. The vulnerability of the root to water coming through the stem may be easily seen by comparing in the spring roots of corn, the stalks of which were cut at different heights the previous fall.
In the hardy border, no large amount of coarse or highly fermentable material should be used. The enrichment of the land should, if possible, be made while preparing the border, and any fertilizers used should be well mixed with the soil. Even if a liberal quantity of stable manure is available, it is well to use some potash or phosphoric acid in connection with it. A light top-dressing of manure given in the fall will keep up the fertility, correct the soil in various ways, and afford a slight winter protection, which is appreciated by even the hardiest plants. Over-richness as well as poverty of soil tend to make plants in general less hardy, but usually a great abundance of plant-food should be given, especially for the hardier species with vigorous constitutions and long season of growth. Many plants having a season of rest in late summer do best in land not overly rich, especially if the position is moist.
A loose and open surface soil prevents baking after rains and waterings; saves some of the labor necessary to keep the soil open and friable; allows the growth of many smaller, finer-rooted or creeping plants that cannot grow well in a stiff soil; permits the sowing of many annuals in the border. Many low-growing plants are injured on clayey soil by having the under surfaces of the leaves coated with earth by spattering of rain. A clay soil may be made more loose by the addition of manures, sawdust, coal-ashes, sand or almost any such material. A light, fine mulch should be kept on the surface of a clay soil.
The points to be borne in mind in planting should be healthy plants, careful planting and sufficient thickness of planting. Plants should be obtained which have not been stunted, as a weakened plant will seldom make as good a specimen as if rightly treated from the start. When plants are received from the nursery they may be heeled-in if necessary, but every day plants are left where they have no root-hold on the soil is an injury to them, in proportion to the suitableness of the weather for root-growth. If plants must remain any considerable length of time before being placed in their permanent position it is best to plant them in reserve ground, and to remove them when desired with balls of earth.
Symmetry of top-growth is to some extent, at least, dependent on symmetry of root-growth, so that by careful planting the roots not only become more quickly and strongly active, but give us hope for a more symmetrical plant than can be secured by careless planting. The proper way to place a plant in the ground is to distribute the roots equally about the plant, leaving the tips pointed downward, and then to firm the soil sufficiently about the roots.
A perennial border should be planted rather thick, so that when in foliage it shall appear as one mass. Any showing of soil between plants is not only unnatural but destroys the beauty of the border as a whole. Of course, if plants are wanted for their individual or separate merits, they should be given full room.
Winter protection of herbaceous perennials.
The protection of species not reliably hardy may be accomplished with any material suitable for keeping out frost which is not naturally too moist or close. The material should preferably be heaped over the crown of the plant to shed part of the rain as well as to prevent quick changes of temperature, or wholly to exclude frost, as the plant may need.
The material to be used will be determined for the plants to be protected, by what is on hand or easily obtainable, and by the presence or not of mice or other vermin, which often work under such material as straw. Protected plants should be examined frequently in the winter, and if mice are present they may be killed or driven away by placing a few drops of carbon bisulfide in each hole found. (This is also a good way to rid coldframes of these pests. Plenty of ventilation should be given at the time, as the gas evaporated is destructive to vegetation. As the gas is heavier than air it sinks for the most part down the holes.) If, however, mice are not troublesome, there is no better material for keeping out cold and shedding water than straw. Nature's plant- protection is to use the foliage and stems of the plant themselves, the whole ground surface being covered as the weather grows colder with successive coatings of snow, which protection again grows lighter as spring approaches. This is still the ideal winter protection for plants, but snows are likely to disappear in midwinter and mice are well adapted to live under heavy litter. Where mice are troublesome, a light material may be made by composting leaves, manure rakings from lawns, greenhouse waste, weeds not in fruit as pulled during the season, and the like. The material should be earthy enough to keep mice out, and loose enough to permit of easy removal in spring. It should also be loose enough not to hold too much water in winter. Sawdust and charcoal are examples of such material.
Most of the plants that are largely cultivated need no protection, but all herbaceous perennials, unless they are evergreen or easily smothered, are benefited by a slight covering to protect the soil from alternate freezing and thawing. If the plants are evergreen, a covering to supply shade is often desirable. Other plants, such as Helianthus decapetalus fl. Pl., really need protection, not to exclude frost but to lessen considerably the severity of the winter. Still others, as many of the lilies, are best covered to the exclusion of frost. In general, the plants that need complete protection have crowns below the surface, and so may be covered with any amount or kind of material. When it is desired thoroughly to protect crowns on the soil surface, flats may be first placed over the crowns before adding the protection. In most cases, late fall plantings should be protected to some extent, since plants are less hardy when poorly established in the soil. See Winter Protection, Vol. VI.
Propagation of herbaceous perennials.
The methods of propagation most used are by seed, by division of the plant, and by cuttings.
Propagation by seed is commonly not of use for the perpetuation of horticultural varieties, although to a varied extent with different species any variety tends to reproduce its characteristics more perfectly the longer it becomes established as a variety. However, some of the garden plants have been separated into their present number of varieties or forms mainly by continual propagation by seed- and plant-selection, and such may be satisfactorily increased by seed. An example might be taken in the hollyhock, although, if a group be left to resow itself, or no seed- selection be maintained, it will soon become mainly composed of single-flowered plants by reason of their greater seed-production. In general, propagation by seeds is satisfactory for all established species and for such varieties and forms as have been thoroughly established by selection.
Seed-sowing is not, however, always an easy way to increase many of our garden plants, as there are often a few small items necessary to know concerning a species before success can be assured. Seeds of some perennials remain dormant for a long period after sowing, and, in general, they are very much slower in starting than annuals. Some require more heat than others to germinate, while others require a very cool soil. Many plants brought into cultivation from foreign countries or milder parts of our own land do not produce seed that will remain sound over winter in the earth, nor do seedlings of all hardy perennials withstand the colder season: for example, Paparer orienlale, a hardy plant itself, produces a great quantity of seed which germinates readily as it falls, but the seedlings will not survive the winter in the northern United States unprotected.
A general rule for seed-sowing would read: Sow the seed when ripe, and then maintain such conditions of temperature and moisture as the seed would receive in the native habitat of the plant. Native American plants not from decidedly milder parts, and many foreign species, may be easily increased by sowing of seed when ripe in the open ground. Among such might be included rudbeckia, aquilegia, coreopsis, monarda, asters (perennial), delphiniums, digitalis, Dianlhus barbatus, and phlox, all of which will bloom the following season.
Plants usually have one or rarely two particular seasons for blooming, and unless of sufficient size and suitable condition when that season approaches, they will wait for its recurrence before showing flowers, so that by sowing seed early in the spring and giving good cultural attention to the plants, we may expect to flower the first year many plants naturally blooming late in the year, or such as are somewhat floriferous at nearly all seasons: for example, Lobelia cardinalis and other lobelias, many of the native asters, Gaillardia arislala var. grandiflora, Bellis perennis, hollyhocks, platy- codon, delphiniums, hardy chrysanthemums, salvias, rudbeckia, dahlias. See Seeds, Vol. VI.
Propagation by division is simply the separation of a larger clump of roots and crowns into smaller plants. In the case of plants producing buds on the roots, this division may be carried further, and small pieces of the root used to grow other plants. The separation of plants as practised in the garden is not usually so much for the purpose of increase as to avoid overcrowding of roots and crowns, with loss of vigor to the plant; for example, a plant of iris, having been undisturbed for a number of years, becomes a tangled circular mat of rootstocks, which in the center cannot find room to grow, and so the plant appears as a large mass of rootstocks, throwing up foliage only on the outer ring. The period in which a plant may remain in any one place without needing separation will vary with the vigor of growth of the plant in each position; a group of plantain lily in a favorable situation will need separation every two years, while in a poorer place it might remain four. However, the average length of time for a few typical species may be given thus: Bellis perennis, pompon chrysanthemums, and other strong-spreading, shallow-rooted and easily established plants do best with yearly separation; Phlox maculata and monarda every two years; helianthus, asters and many of the composite and Phlox decussala about every three years; Convallaria majalis and many spring-flowering bulbs every four years; such plants as peonies may be left for a longer period.
In general, better flowers are secured from a plant with but one crown than when two or more are left, but unless the new growths are crowding out the central parts or are themselves too numerous to make a vigorous growth possible, division is not necessary. In fact, many plants require a better establishment in the soil than can be given by transplanting or than they can quickly secure, and such are best undisturbed until quite overcrowded. The question is whether by dividing a plant better flowers and foliage may be obtained than by allowing it to become more thoroughly established.
The time of year for separation will vary as to the blooming season of the plant; that is, for early-blooming plants late summer or early fall, and for late- blooming plants either late fall or spring, preferably the latter, as many otherwise hardy plants are either weakened or killed if disturbed in fall. See Separation, Vol. VI.
Propagation by cuttings is rarely useful for the amateur, in the case of herbaceous perennials, but it is an important commercial method. Plants may be obtained from almost any plant having foliage-stems by taking a short piece of the growing wood with a bud, either lateral or terminal, and placing the lower end in moist sand or other material suitable for root-growth. It is usually necessary to have the lower end of the cutting a node or joint of the stem, and to make the temperature of the material in which it is placed higher than that of the atmosphere (which is the relation of the soil and air in sunshine), and to diminish the evaporation from the exposed parts of the cutting by maintenance of a moist atmosphere and by removal in part of the foliage on the cutting. Some experience will be necessary to know the best temperatures for sand and atmosphere and the most desirable degree of ripeness in the wood to be taken, as they will vary somewhat with species. In general, any cutting of growing wood will form roots in moist sand at a temperature suitable for vigorous root- growth of the plant. See Cuttings. Vol. II.
The increase of plants by cuttings has the advantages of being rapid and of allowing the perpetuation of any variation noticed on a portion of any plant.
Whichever method of propagation is used, selection of stock for increase should be practised. If by seed, then the best seed from the best plant should be taken. It is considered that seeds borne the least number of nodes from the root tend to produce dwarfer and earlier-blooming plants, while the opposite is equally certain. All plants vary, and often the seeds that will produce the mast striking variations are the slower to germinate and are weaker.as seedlings, but any mistreatment of young plants is likely to be against any desirable improvement. The double-flowered and highly colored forms of garden plants are generally the results not only of intercrossing of species or selection, or both, but of intense and perfect culture. A poor, starved plant may not retrograde itself, but it is likely to produce seed which will vary.
Variations in plants are the result of climatic, soil, cultural, and other conditions, and such plant forma are unstable when the conditions which caused them are radically changed. Any new variety naturally reproduces itself best in the region in which it originated, and may easily revert or otherwise change when grown under different conditions. This is especially true in the reproduction by seed of plant variations. See Breeding, Vol. I.
In propagating by division, the aim should be not only to secure vigorous plants but to select for increase such plants as appear to be the best. Cuttings also should be taken from selected plants—and the more so since the method is rapid. F.W. Barclay.
|This article contains a definition from the Glossary of Gardening Terms.|