Ohio Perennial and Biennial Weed Guide

Jan. 6, 2014

Need help in Identifying weeds or other native plants in your garden or woodlands?

The OARDC at Wooster has created a photo key to make it easy to for the casual user.


Photo Key This photo key of perennial and biennial weeds is intended to help the casual user identify a weed. Weeds that look similar are grouped together. So look before and after what you may think to be your weed to make sure you haven't misidentified it. Clicking on a photo will bring up a larger version and clicking on the name will bring open the entire record with additional photos and information.



Alphabetical Listing of Perennial and Biennial Weeds


Example below....................

Taraxacum officinale

Other Names | Origin & Distribution | Plant Description | Similar Species | Biology | Toxicity | Facts & Folklore


Dandelion seeds without pappus. Dandelion seedhead waiting for a breeze. Young dandelion rosette. Dandelion flowers are a common cheerful sight in turfgrass. Dandelions infesting a no-till corn field in springtime.

Family: Daisy Family (Compositae)

Other Names: Lentodon taraxacum, bitterwort, blow-ball, cankerwort, clockflower, common dandelion, Irish daisy, lion's tooth, piss-in-bed, pissinlit, priest's crown, puffball, swine's snout, telltime, yellow gowan.

Origin and Distribution: Probably a native of Eurasia, dandelion is now widespread in North America (found in all 50 states and southern Canada) and over 60 countries throughout the world. It has been suggested that dandelion may be the most prevalent flowering plant in Ohio. It is common in lawns, pastures, roadsides, waste places, and is rapidly becoming a troublesome weed in agronomic fields under reduced tillage regimes. The species requires moist soil and sunlight in order to establish and thrive.

Plant Description: This perennial herb is distinguished by its basal leaves with jagged edges, hollow stems that are leafless and terminate in a single yellow flower, and fluffy white seed heads. At maturity, all plant parts exude a milky juice if cut. Reproduce is by wind-blown seeds. Also, plants regenerate from root fragments.

  • Root system - The species has a deep, thick, branched taproot that exudes a milky juice if cut.
  • Seedlings & Shoots - Seed leaves (cotyledons) are pale, dull, yellowish-green, oval, and have smooth edges. Young leaves form a basal rosette and are oval to oblong with long hollow leaf stalks (petioles).
  • Stems - Stems are erect, 2 to 12 inches tall, hollow, leafless, filled with milky juice, and terminate in a single flower head.
  • Leaves - Leaves are basal, bright green, thin, hairless, between 3 to 10 inches long, and jagged around the edges with lobes or teeth of various sizes and shapes. The terminal lobe is usually largest and lobes become smaller and more deeply divided toward the leaf base. Leaves are alternate (1 leaf per node), which is difficult to distinguish because stems are so compressed that nodes are generally at or below the soil surface. The leaf base tapers into a hollow, short petiole. Mature leaves exude a milky juice when cut or broken.
  • Flowers - The bright yellow, 1- to 2-inch-wide flowers form at the tips of long, hollow, flower stems. Flowers mature into fluffy white seed heads.
  • Fruits & Seeds - The single-seeded fruits are brownish, narrow, about 3/16 inch long, and tapering to a slender beak that is 2 to 3 times as long as the seed. At the top of the beak are soft, white, bristly hairs (pappus).


Similar Species: Rosette leaves of chicory (Cichorium intybus) closely resemble those of dandelion except the basal leaves of chicory are coarser and have more prominent hairs. Coltsfoot (Tussilago farfara) and dandelion flowers and seed-heads look similar but dandelion flower stems are much more slender and smooth and its flowers appear at the same time rather than before the leaves emerge. Dandelion and common catsear (Hypochoeris radicata) are easily confused due to similarities in the flowers and leaves. However, common catsear has hairy leaves with irregular rounded lobes and its stems have leaf-like bracts and branches.

Biology: Flowers form mostly in April and May, but flowers have been known to appear as early as February and as late as June. In some locations, secondary flowering occurs in autumn. Plants generally remain vegetative and do not initiate flowering until a satisfactory number of leaves form. Therefore, plants growing in tall grass without ample moisture and sunlight will usually not flower and may not survive. Total sunlight received determines leaf shape; plants growing in full sun have deeply-toothed, thick, green leaves compared with shade leaves that are slightly-toothed, thin, and pale. Estimates of the number of seeds produced per plant each year range from 3,000 to 23,000.

Toxicity: None known.

Facts and Folklore:

  • Dandelion is from the French 'dent de lion' or 'lion's tooth and refers to the jagged-edged leaves.
  • Because dandelion is a powerful diuretic, it was called such common names as 'piss-in-bed' and 'pissinlit'.
  • The genus name is possibly from the Persian 'tarashquan' meaning 'bitter potherb' referring to the plant's culinary uses.
  • The species name, 'officinale', means 'official' or 'sold in shops' and was likely assigned because dandelion was sold in the market place.
  • Dandelion was used medicinally to treat constipation, rheumatism, and other complaints.
  • Young leaves of dandelion can be eaten as salad greens, flowers are used to make wine, and dandelion coffee is made from roasted roots.
  • Although leaves become bitter and unpalatable with age, they usually regain some of their sweetness after the first frost.
  • Dandelions contain vitamins A and C in relatively large quantities.