Asparagus has naturalized itself throughout the United States. The plant is erect with branching from the main stem and can grow to 7 feet in height, from underground rhizomes that are spreading and form colonies. The plant is just like your garden asparagus, and when left to grow, the central stem reaches upward and develops side branches.
Leaves: From these side branches develop whorls of small very short branchlets (see photo far below), technically known as cladophylls, which perform the function of leaves but are not true leaves at all, but reduced branches. This foliage on these side branches looks feathery. On the main stem are the true leaves which are reduced to small scales. It is from these scale nodes that the side branches arise.
Flowers: At the base of the whorl of side branches in May and June come the flowers in opposite pairs. They are greenish to white, 6 part, stalked, with oblong tepals forming a tubular or bell shape, about 1/3 inch long. They are either all male or all female (plants are dioecious). Male flowers have 6 stamens with orange anthers and white filaments (not protruding) and can be more bell shaped. Female flowers have a pistil with a 3-stigma style and are more tubular. The ovary is green and in 3-sections. Pollination is by insects.
Fruit: The flowers mature to a round red berry 1/8 to 1/4 inches diameter that contains 3 to 6 seeds that are black, kidney to ellipsoid shape, 4-4.5 mm long x 2.5-3 mm wide.
Habitat: The plant needs full sun and moist to slightly dry soil such as found in upland places, fields, roadsides and open woods.
Names: The genus Asparagus is the old classical name for this plant, known since ancient times. The species name officinalis refers to being 'sold in shops' and is used when plants have known or supposed medicinal qualities. The author name for the plant classification, 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. Some references have now placed this plant in the Asparagaceae family, but that is not universal.
Comparisons: Not likely to confuse, although young shoots of Blue and White False Indigo somewhat resemble Asparagus shoots. Also, young shoots of the various milkweeds and of Prairie Dogbane may confuse the unwary.
Above: The bell shaped male flowers appearing in pairs. The plant looks just like your garden asparagus, and when left to grow, the central stem reaches upward and develops side branches. From these side branches develop whorls of small very short branchlets (cladophylls) (see photos below). Those triangular shaped scales on the main stem (photo above) are the true leaves.
Below: The short leaf-like whorls on the side branches give a feathery appearance. These are technically known as cladophylls, which perform the function of leaves but are not true leaves at all, but reduced branches. As the plant matures, the branchlets drop away and only the branching structure remains with the fruit. Following a burn of the prairie, asparagus shoots are quick to grow.
Below: 1st photo - The female flower with 3-part green ovary and 3-stigma style. 2nd photo - A male flower. The yellow anthers of the six stamens cluster together. 3rd photo - Internal structure of the male flower.
Below: Green berries developing in June on a side branch. The flowers originally formed at the base of the small branchlets that grow perpendicularly from the side branch.
Below: Mature berries of Autumn. Note on the top of each berry are the remains of the tepals of the flower. The red berries of Autumn with some of the cladophylls still remaining on the branch
Below: Mature seeds - Kidney shape to ellipsoid shape.
Below: A mature roadside plant with many berries.
Notes: Asparagus is an introduced garden plant from the old world that is found in all the lower 48 states and the lower Canadian Provinces. In Minnesota it is found in the wild in most counties with widely scattered exceptions. It is considered indigenous to the Garden as Eloise Butler catalogued it on May 31, 1907.
Lore and Medicinal Use: Asparagus is known in Europe from ancient times. In England it was not widely found but as far back as 1597 it was noted by Gerard (Ref. 6a. Gerard's Herball). It was common in Greece and was apparently cultivated by the Greeks and Romans. Pliny the Elder references it growing near Ravenna. The plant itself is known to have diuretic and laxative qualities and Culpepper (Ref. 4b) gives the following use, among others, in The English Physician:,"The decoction of the roots boiled in wine, and taken, is good to clear the sight, and being held in the mouth easeth the toothache."
Harrington (Ref. 9) references the use of the roasted and ground seeds of asparagus as a coffee substitute but notes that an earlier work by Fernald cautions that the seeds may be poisonous. Tilford (Ref. 39) also attests to this and adds that asparagus, like broccoli and spinach "contain potentially carcinogenic alkaloids - but you would have to eat a truckload ... over a short period of time to experience any poisoning effect. Coffee contains thirteen or so 'toxic' alkaloids."
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"