WILD GARLIC Its Characteristics and Control

L-v'-l ' ^ WILD GARLIC Its Characteristics and Control Agriculture Handbook No. 298 Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE In Cooperation With Missouri Agricultural Experiment Station CONTENTS Page Origin and distribution. _ 3 Plants that resemble wild garlic 4 Description and growth habit 5 Classification ^ Structure of the wild garlic plant 6 Plant types 6 Bulb types 7 Reproductive cycles 10 Wild garlic: a pest ^^ Pest in small grains 14 Pest of pastures and hay fields 1^ Pest around homes, gardens, and noncrop areas.. 15 How wild garlic spreads. 1^ Control and eradication 1^ Cultural control 1^ Chemical control 1^ Precautions __ ^1 Parasites and diseases 20 Literature cited 22 Washington, D.C. Issued December 1965 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C, 20402 - Price 15 cents WILD GARLIC Its Characteristics and Control By Elroy J. Peters, J. F. Stritzke, and Frank S. Davis, Crops Research Division, Agricultural Research Service ^ Wild garlic {AlUum vineale L.) is a troublesome weed in the United States. Significant losses result from the "onion" odor and flavor that wild garlic gives to milk, small grains, and meat products. Other conunon names that have been used for Allium vineale L. are field garlic, meadow garlic, garlic, onion, crow garlic, wild onion, and vineyard garlic (5, 27),^ ORIGIN AND DISTRIBUTION The geographical origin of wild throughout western and central garlic is diflScult to determine. It Europe where it is found as far probably originated in the area of north as southern Norway, Sweden, the Mediterranean Sea {18), and Finland; and east to the Wild garlic is found in many Dneiper, Crimea, and Transcauca- areas of the world. It has spread sian regions of the U.S.S.R. (Í5, 31), It is rare in Austria ; fairly common in Hungary, Italy, Spain, and Portugal {12) ; and has been re- ^ Dr. Peters and Mr. Stritzke are at the Missouri Agricultural Experiment Sta- ported in North Africa and the tion ; Dr. Davis is at the Texas Agricul- Canary Islands {12), Wild garlic tural Experiment Station. has spread from Europe to Aus- This handbook was prepared in cooperation with the Field Crops Department, Missouri Agricultural Experiment Sta- tion, and is published with the approval of the director. (Journal Series No. ^ Italic numbers in parentheses refer to 2731.) Literature Cited, p. 22. tralia (2), New Zealand {36}, and garlic head was present for every the United States. Is is particMi- nine heads of wheat {28). larly troublesome in Sweden, Eng- Wild garlic has continued to land, and the United State« (13, 20, spread and now infests a large part 27, 28), of the United States. It grows as Wild garlic was probably intro- far south as Georgia, Mississippi, duced into the United States from and Arkansas ; and as far north as France in the 17th or early pari: of Massachusetts, New York, Ohio, and Michigan {10), It is a serious the 18th century {3,15). After its pest on the eastern seaboard and introduction into the United States, extends west to Kansas and Okla- it became a serious weed problem. homa {30). Wild garlic has been Pipal cited a report showing that as mentioned as the cause of garlic- early as 1754, in Philadelphia, an flavored milk in Wyoming {6). infestation of wild garlic in a Infestations also are present in wheatfield w^as so heavy that one western Oregon and Washington.'^ PLANTS THAT RESEMBLE WILD GARLIC In the United States, wild garlic flowers appear, and then the plants sometimes grows in association with mature and disappear before warm other bulb formers such as Omitho- weather. Star-of-Bethlehem sel- gahim mnbeJlatum L., AJlhim ole- dom grows over 8 inches tall. It Tdceum L,, A. cernuuinx Roth, A. has flat leaves, which have a white Tïiutahïle Michx., A, canadense L., stripe down their center (fig. 1, A). Hemerocallis fulva L., and Ziga- The leaves arise from the base of denus Nuttallii Gray. the plant. The terms "wild garlic" and Wild garlic can be distinguished "wild onion" are often used inter- from wild onion and star-of-Beth- changeably for many of the bulb lehem by its striate, nearly round formers. In the United States, the hollow leaves (fig. 1, C), which are species most commonly found with attached at the lower half of the wild garlic are wild onion {A, cana- plant. Wild onion and star-of- dense L.) and star-of-Bethlehem Bethlehem have their solid flat {Omithogolum unnbellatuni L.). leaves attached at the base of the The wild onion, like wild garlic, plant. Moreover, wild garlic has begins growth in mid-August or underground hardshell bulbs, which early September and matures in late are absent on wild onion and star- May or early June. Wild onion of-Bethlehem. Also, the old bulb grows 1 to 2 feet tall. It has flat coat of wild garlic is thin and mem- leaves (fig. 1, 5), which arise from braneous, but the coat of wild onion the base of the plant. is fibrous matted. Star-of-Bethle- Star-of-Bethlehem often is plant- hem does not have the "onion" odor ed as an ornamental and then of wild garlic or wild onion. spreads to lawns, gardens, yards, and waste places. It begins growth ^ Personal communication from Dr. soon after the ground thaws in Marion Ownbey, Dept. of Botany, Wash. early spring. Small, showy white State Univ. \ Figure I.—Cross sections of leaf blades of star-of-Bethlehem, wild onion, and wild garlic: A, Leaf of star-of-Bethlehem showing white striation at the center of the solid flat leaf; B, flat solid leaf of wild onion; C, round, hollow leaf of wild garlic. DESCRIPTION AND GROWTH HABIT Classification be classified as belonging to the Am^aryllidaceae family. Five varieties or forms of Allium, Wild garlic is a bulbous perennial vineale L. have been described in monocot that has classically been in- the United States {15). These are : cluded in the Liliaceae family. {a) forma ty2)icum Beck, with a However, Hutchinson (i^) includes loose umbel containing both aerial Allium in the Amaryllidaceae fam- bulblets and flowers; (6) forma ily. He considers the umbellate comfactum Thuill, with a compact inflorescence to be of greater taxo- head consisting only of aerial bulb- nomic importance for classification lets, which are greenish or whitish ; (c) forma fuscenscens Ascherson than the character of superior or and Graebner, with a head contain- inferior ovary, wliich is usually ing reddish bulbils; {d) forma used to distinguisli Liliaceae from crinitum Jacob, with bulbils on the Amaryllidaceae. His views have head tipped with long, green, capil- been supported by other workers lary appendages; and (e) forina (5, 26); and at present (1965) it capsidiferum Koch, with a umbel appears that Allium will eventually consisting of flowers only. Three forms of wild garlic have The flowers have a greenish to been identified in England, but purple perianth with lanceolate to their status as varieties has been elliptic segments. The segments questioned by Richens (31). Tran- are obtuse to acutish and about as sitions between forms are often long as the stamens {10). Seeds of noted, and they appear to be de- the scapigerous plant are black, pendent upon Mendel i an allelic flat on one side, and about one- genes {15). Most AlUuni species eighth inch long. have 16 chromosomes, but Allium The nimiber of scapigerous vineaJe L. has 32 chromosomes, a plants in a wild garlic stand varies. number that indicates that A. Under conditions in the British vineale L. is tetraploid {15). Apog- Isles, Richens observed that about amy is a common occurrence in A. 30 percent of the wild garlic popu- vineale. lation consists of scapigerous plants Iltis {15) also observed what he in any one season {31). The rest thought to be genetic differences in of the population was made up of color of aerial bulblets. Seed from nonscapigerous plants (fig. 5), plants with purple bulblets pro- which are shorter and less con- duced plants with purple leaf spicuous than the scapigerous sheaths and seed from plants with plants. green bulblets produced plants with green leaf sheaths. Structure of the Wild Garlic Plant Wild garlic looks much like the cultivated onion. Figure 2 shows a clump of wild garlic as seen in spring. The leaves are two-ranked and have sheathing bases. The leaf blades are circular in cross section and hollow. The outer layers of a bulb of a growing wild garlic plant are formed from the sheathing bases of the foliage leaves. Plant Types Wild garlic consists of two plant types—scapigerous and nonscapigerous. The larger, scapigerous Figure 2.—A typical dump of wild garlic in the plant bears a scape, which produces spring, showing growth habit and plants of various sizes. The larger upright plants are aerial bulblets (fig. 3) and some- «capigerous and the smaller plants are non- times flowers (fig. 4). scapigerous. Nonscapigerous plants have slen- clature suggested by Davis and der foliage and fewer leaves, and Peters (7) will be used in this do not produce a scape at the end publication. of the growmg season. Aerial Bulblets Bulb Types As many as 300 aerial bulblets (fig. 6, Ä) may be formed on the Four types of bulbs can be found scape of a scapigerous plant (fig. on wild garlic at the end of a sea- 3). son's growth in late spring. Vari- The bulblets develop within a ous names have been given to the spathe (a large, dry, thin, mem- bulb types. The system of nomen- branous bract) at the top of the scape.

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