There are about 150 kinds of asparagus besides the edible oneall are members of the lily family. Those described here are native to South Africa. Best known is asparagus fern (A. setaceus), which is not a true fern. Although valued mostly for handsome foliage of unusual textural quality, some of the ornamental species have small but fragrant flowers and colorful berries. Green foliage sprays are made up of what look like leaves. Needlelike or broader, these are actually short branches called cladodes. The true leaves are inconspicuous dry scales.
Most ornamental asparagus look greenest in partial shade. Leaves yellow in dense shade. Plant in well-drained soil amended with peat moss or ground bark. Thanks to their fleshy roots, plants can go for some time without water, but they grow better when watered regularly. Feed in spring with complete fertilizer. Trim out old shoots to make room for new growth. Ornamental asparagus will survive light frosts but may be killed to ground by severe cold. After frost, plants often come back from roots.
A. asparagoides. SMILAX ASPARAGUS. Much-branched vine with spineless stems to 20 ft. or more. Often seen in older gardens. Leaves to 1 in. long, sharp pointed, somewhat stiff, glossy grass-green. Small, fragrant, white flowers in spring followed by blue berries. Fleshy roots are nearly immortal, surviving long drought, then sprouting when rains come. Foliage sprays are prized for table decoration. If it doesn't get much water, plant dies back in summer, revives with fall rains. Becomes a tangled mass unless trained. This asparagus may escape gardens and become an invasive pest, as birds feed on the berries and drop seeds later; plants also self-sow readily. 'Myrtifolius', commonly called baby smilax, is a more graceful form with smaller leaves.
A. crispus. BASKET ASPARAGUS. Airy, graceful plant for hanging baskets. Drooping, zigzag stems have bright green, three-angled leaves in whorls of three. Often sold as A. scandens 'Deflexus'.
A. densiflorus. The species is less commonly grown than its cultivated forms; the following are the two most popular. Plants are seldom browsed by deer.
'Myersii'. MYERS ASPARAGUS. Several to many stiffly upright stems to 2 ft. or more, densely clothed with needlelike, deep green leaves that give the plant a fluffy look. Forms a 3- to 4-ft.-wide clump. Good in containers. A little less hardy than 'Sprengeri'. May be sold as A. meyeri or A. myersii.
'Sprengeri'. SPRENGER ASPARAGUS. Arching or drooping stems 36 ft. long. Shiny, bright green, needlelike leaves, 1 in. long, in bundles. Bright red berries. Popular for hanging baskets or containers, indoors and out. Train on trellis; climbs by means of small hooked prickles. Used as billowy ground cover where temperatures stay above 24F. Grows in ordinary or even poor soil. Will tolerate dryness of indoors. Sometimes sold as A. sprengeri. Form sold as 'Sprengeri Compacta' or A. sarmentosus 'Compacta' is denser, with shorter stems.
A. falcatus. SICKLE-THORN ASPARAGUS. Leaves are 23 in. long and very narrow, resembling flattened pine needles; they are borne in clusters of three to five at ends of branches. Tiny, fragrant, white flowers in loose clusters are followed by brown berries. The plant derives its common name from curved thorns along its stems, which it uses to clamber rapidly as high as 40 ft. in its native area (in gardens, it usually reaches about 10 ft.). Makes an excellent foliage mass to cover fence or wall or provide shade for pergola or lathhouse.
A. officinalis. See Asparagus, edible
A. retrofractus. Erect, shrubby, slightly climbing, very tender. Slender, silvery gray stems grow slowly to 810 ft. high. Threadlike, inch-long leaves, in fluffy, rich green tufts. Clusters of white flowers. Handsome in containers; useful in flower arrangements. Cut foliage lasts about 10 days out of water, several weeks in water.
A. scandens. BASKET ASPARAGUS. Slender, branching vine climbing to 6 ft. Deep green, needlelike leaves on zigzag, drooping stems. Tiny greenish white flowers; scarlet berries.
A. setaceus (A. plumosus). ASPARAGUS FERN. This branching, woody vine climbs by wiry, spiny stems to 1020 ft. Tiny threadlike leaves form feathery, dark green sprays that resemble fern fronds. Tiny, white flowers; purple-black berries. Forms a dense, fine-textured foliage mass that is useful as screen against walls and fences. Florists use foliage as filler in bouquets; it holds up better than delicate ferns. Dwarf 'Nanus' is good in containers. 'Pyramidalis' has upswept, windblown look, is less vigorous than the species.