ornamental flower stand, 1841, from French jardinière "flower pot" (also "female gardener, gardener's wife"), noun use of fem. of adjective jardinier "of the garden," from jardin "garden; orchard; palace grounds," from Vulgar Latin *hortus gardinus "enclosed garden," via Frankish *gardo or some other Germanic source, from Proto-Germanic *gardaz, from PIE root *gher- (1) "to grasp, enclose."
Two square feet, or four at most, in one corner of the frame, will give you mustard and cress a plenty for salads, if you take care to make repeated sowings in proper time. [William Cobbett, "The English Gardener," 1829]
But perhaps older, depending how some uses of aplenty or a plenty are read.
An extensive bridge consisting, strictly of a series of arches of masonry, erected for the purpose of conducting a road or a railway a valley or a district of low level, or over existing channels of communication, where an embankment would be impracticable or inexpedient; more widely, any elevated roadway which artificial constructions of timber, iron, bricks, or stonework are established. [Century Dictionary]
But the word apparently was coined by English landscape gardener Humphry Repton (1752-1818) for an architectural feature, "a form of bridge adapted to the purposes of passing over, which may unite strength with grace, or use with beauty ...."
1852, from German Kinder-Garten (1840), literally "children-garden, garden of children," a metaphoric name from Kinder "children" (plural of Kind "child;" see kin (n.)) + Garten "garden" (from suffixed form of PIE root *gher- (1) "to grasp, enclose"). Coined by German educator Friedrich Fröbel (1782-1852) in reference to his method of developing intelligence in young children. Compare the double sense in nursery
Kindergarten means a garden of children, and Froebel, the inventor of it, or rather, as he would prefer to express it, the discoverer of the method of Nature, meant to symbolize by the name the spirit and plan of treatment. How does the gardener treat his plants? He studies their individual natures, and puts them into such circumstances of soil and atmosphere as enable them to grow, flower, and bring forth fruit,-- also to renew their manifestation year after year. [Mann, Horace, and Elizabeth P. Peabody, "Moral Culture of Infancy and Kindergarten Guide," Boston, 1863]
The first in England was established 1850 by Johannes Ronge, German Catholic priest; in America, 1868, by Elizabeth Peabody of Boston, Mass. Taken into English untranslated, whereas other nations that borrowed the institution nativized the name (Danish börnehave, Modern Hebrew gan yeladim, literally "garden of children"). Sometimes partially Englished as kindergarden (a form attested by 1879).