Ohio Noxious Weed Identification – Week 16 Poison Hemlock

Poison Hemlock

Family: Parsley, Apiaceae.

Habitat: Wet sites, gardens, roadsides, wastelands, pastures, and meadows.

Life cycleBiennial, forming a rosette the first year and producing flowers and seed in the second.

First Year Growth HabitBasal rosette of finely divided leaves with a pungent odor.

Second-Year Growth Habit: 2-7 feet tall, branched plant with flowers.

LeavesAlternate, pinnately compound, finely divided, toothed, and glossy green.

Stems: Branched, waxy with purple blotches; hollow between nodes and grooved.

FlowerJune – August (second year). Clusters of small white flowers with 5 petals in a loose, umbrella-like cluster, 2-7” across.

Root: Fleshy taproot.

Similar plants: During the first year, poison hemlock resembles wild carrot, but has a strong, pungent odor. Further, young leaves of wild carrot are more finely divided and its stem is hairy. At maturity, poison hemlock can be difficult to distinguish from water parsnip and water hemlock. Look for purple blotches on the stem to identify poison hemlock. Water hemlock (Cicuta maculata), which is also highly poisonous, has a magenta-streaked stem and lanceolate leaflets with sharply-toothed edges. Water parsnip (Sium suave) is not poisonous and has toothed lanceolate leaflets.

The problem is….This plant is highly poisonous to both humans and animals. Poison hemlock is a large and impressive plant which has been planted as an ornamental in some areas. It grows quickly in fertile soils.

Continue reading Ohio Noxious Weed Identification – Week 16 Poison Hemlock

Ohio Noxious Weed Identification – Week 15 Johnsongrass

Johnsongrass

FamilyGrass, Poaceae.

Habitat: Rich soils, cultivated fields throughout Ohio.

Life cycle: Perennial, spreading by rhizomes and seed.

Growth Habit: 3-6 feet or more.

Leaves: 0.5 -1 inch wide, smooth blades with a prominent white midvein.

Flower: July – October. Can be up to 1 foot or more in length; panicles are loosely branched, purplish, and hairy. spikelets occur in pairs or threes.

Continue reading Ohio Noxious Weed Identification – Week 15 Johnsongrass

Ohio Noxious Weed Identification – Week 14 Wild Parsnip

Wild Parsnip

FamilyParsley, Apiaceae.

Habitat: Wastelands, wet sites, roadsides and pastures, undisturbed ground.

Life cycle: Biennial, forming a rosette the first year and producing flowers and seed in the second.

First Year Growth Habit: Rosette of basal leaves. Large, three-lobed leaves resemble celery.

Second Year Growth Habit: 2-5 feet, branched, flowering plant.

Leaves: Alternate, pinnately compound with coarse saw-tooth edges; deeply lobed and not hairy. Up to 18 inches long.

Stem: Hairy and grooved.

Flower: May-August (second year). Many small flowers with five yellow or white petals borne in umbrella shaped terminals – gives rise to yellow seed clusters, 2-6 inches across.

Continue reading Ohio Noxious Weed Identification – Week 14 Wild Parsnip

Ohio Noxious Weed Identification – Week 13 Oxeye Daisy

Oxeye Daisy

Family: Composite, Asteraceae.

Habitat: Meadows, roadsides, old pastures, and areas low in fertility.

Life cycle: Perennial; spreads by rhizomes and seeds.

Growth Habit: Erect, 1-3 feet high.

Leaves: 1-3 inches long; alternate, dark green, simple, lobed – especially the larger basal leaves. Basal leaves have large petioles.

Stem: Smooth; may or may not be branched.

Flower: June – August. Typical daisy-like flowers with white outer petals and yellow centers which are depressed in the center. Flowers are 1-2 inches in diameter and solitary on the stem.

Continue reading Ohio Noxious Weed Identification – Week 13 Oxeye Daisy

Ohio Noxious Weed Identification – Week 12 – Kochia

Kochia

FamilyGoosefoot, Chenopodiaceae.

Habitat: Agronomic crop fields, pastures, and roadsides.

Life cycle: Summer annual.

Growth habit: Erect with much branching.

Leaves: Occur alternately along the stem.  Leaves are linear to lanceolate in outline, ranging from 1 to 2 inches in length, and taper to a point.  Leaves do not occur on petioles (sessile) and usually only have hairs along the leaf margins.

Stem: Erect, ranging from 1 to 4 feet in height.  Stems are much branched and often have a reddish tint.

Flower: Occur in clusters at the ends of stems (terminal panicles) and also in the position between the leaf bases and stems (leaf axils).  Flowers are relatively inconspicuous, green in color, and approximately 5 to 10 mm long.  Flowers have distinctive hairy bracts beneath which tends to give the flowering stems a ‘prickly’ appearance.

Continue reading Ohio Noxious Weed Identification – Week 12 – Kochia

Ohio Noxious Weed Identification – Week 11 Purple Loosestrife

Purple Loosestrife

FamilyLoosestrife, Lythraceae.

Habitat: Wet meadows, flood plains, wetlands, ditches.

Life cycle: Perennial.

Growth Habit: Usually 2- 4 feet tall, but may reach up to 10 feet in nutrient-rich habitats.

Leaves: Opposite or whorled, 1.5-4 inches long with smooth margins, lacking petioles. Lower leaves have downy hairs and clasp the stem.

Stem: Stiff, 4-sided, woody at the base.

Flower: July to early September. Long spikes of rose or purple flowers, each with 4-7 wrinkled petals.

Continue reading Ohio Noxious Weed Identification – Week 11 Purple Loosestrife

Ohio Noxious Weed Identification – Week 10 Kudzu

Kudzu

FamilyLegume, Fabaceae.

Habitat: Woodland edge, roadsides, rights-of-way, abandoned fields, fencerows.

Life cycle: Herbaceous to semi-woody perennial that dies back to ground each year in its northern range.

Growth Habit: An aggressive, high-climbing or sprawling vine that may grow 30m in a single season.

Leaves: Leaves are trifoliate, with the center leaflet poised on a longer stalk. Leaflets may be lobed or unlobed. Leaves are hairy beneath and along the margins, and are alternately arranged on the stem.

Stems: Young stems are densely hairy and gold in color.

Flower: Clusters of pink pea-like flowers with a grape aroma; produced occasionally in late summer in full sun. Fruit is a brown pod.

Roots: Deep, tuberous roots cluster from a large root crown. First year roots densely hairy.

Continue reading Ohio Noxious Weed Identification – Week 10 Kudzu

Ohio Noxious Weed Identification – Week 9 Japanese Knotweed

Japanese Knotweed

FamilySmartweed, Polygonaceae.

Habitat: The species occupies a wide variety of habitats in many soil types and a range of moisture conditions. It is most common along roadsides and on stream banks, but is also found in low-lying areas, utility rights-of-way, old home sites and along woodland edges and openings. The species requires a high light environment and grows poorly under full forest canopies. In Ohio this species is primarily found in the eastern part of the state.

Life cycle: Semi-woody perennial.

Growth habit: Semi-woody perennial that grows in large clumps reaching heights of 3-10 feet.

Leaves: Alternate and egg-shaped (4-6 inches long and 3-4 inches wide) narrowing to a point at the tip.

Flower: Tiny (1/8 inch) flowers are creamy white to greenish white and are borne in plume-like clusters in the upper leaf axils. The species is dioecious, producing male and female flowers on separate plants, however male plants are rare, flowers bloom in August – September.

Root: Fibrous, spreads primarily by its extensive rhizomes creating dense thickets.

Stem: Stout, hollow stems are reddish brown and the nodes are swollen giving them a bamboo-like appearance. Typical of the smartweed family, nodes are enclosed by a modified leaf-life structure. Stems die back in the winter and new ones are produced each spring.

Similar Plants: Resembles bamboo because of the robust hollow stems with distinct nodes and internodes; however, true bamboo is a grass.

The problem is…Japanese knotweed grows quickly and aggressively by extensive rhizomes and forms dense thickets that exclude native vegetation and reduce wildlife habitat. This species represents a significant threat to riparian areas where it can spread easily as small pieces of rhizome are washed downstream and deposited to create new colonies. Transfer of soil containing rhizome or seed may also cause the establishment of new colonies. Establishment can be prevented with careful monitoring and eradication of small patches when they first develop.

Seedling

Leaves

 

 

 

 

 

Red Stem and Swollen Nodes

Flower

 

 

 

 

 

Currently there are 21 weeds on the Ohio Prohibited Noxious Weed List:

  • Shattercane (Sorghum bicolor) – February 8
  • Russian thistle (Salsola Kali var. tenuifolia) – February 22
  • Johnsongrass (Sorghum halepense L. (Pers.))
  • Wild parsnip (Pastinaca sativa)
  • Wild carrot (Queen Anne’s lace) (Daucus carota L.)
  • Oxeye daisy (Chrysanthermum leucanthemum var. pinnatifidum)
  • Wild mustard (Brassica kaber var. pinnatifida)
  • Grapevines: when growing in groups of one hundred or more and not pruned, sprayed,cultivated, or otherwise maintained for two consecutive years. – February 15
  • Canada thistle (Cirsium arvense L. (Scop.)) – March 29
  • Poison hemlock (Conium maculatum)
  • Cressleaf groundsel (Senecio glabellus)
  • Musk thistle (Carduus nutans)
  • Purple loosestrife (Lythrum salicaria)
  • Mile-A-Minute Weed (Polygonum perfoliatum) – March 7
  • Giant Hogweed (Heracleum mantegazzianum) – March 14
  • Apple of Peru (Nicandra physalodes) – February 28
  • Marestail (Conyza canadensis)
  • Kochia (Bassia scoparia)
  • Palmer amaranth (Amaranthus palmeri)
  • Kudzu (Pueraria montana var. lobata)
  • Japanese Knotweed (Polygonum cuspidatum) – April 2

Each week, for the next 21 weeks, I will post information and pictures on how to identify these invasive and harmful plants.

Ohio Noxious Weed Identification – Week 8 Canada Thistle

Canada Thistle

Family: Composite, Asteraceae.

Habitat: Pastures, crops, landscape areas throughout Ohio.

Life cycle: Perennial with creeping roots.

Growth Habit: 1-3 feet high, erect, branched; forming large patches.

Leaves: 3-8 inches long, alternate with spiny, crinkled margins; lower leaves are lobed.

Stems: Grooved and becoming hairy with age; not spiny; branched at apex.

Flower: Lavender flower heads about 1 inch wide and long. Flowers are surrounded by bracts without spiny tips.

Fruits: Seeds borne in white feathery structures, similar to dandelion, spread by wind.

Roots: A creeping root system allows this weed to spread aggressively. Hand-pulling and cultivation are often ineffective control mechanisms because new plants sprout from root pieces that snap off.

Similar plants: Stems of Canada thistle are not spiny in contrast to bull thistle (Cirsium vulgare) and nodding thistle (Carduus nutans).

The problem is…. An aggressive, spreading root system. Very competitive with field crops and forages. Canada thistle is also prolific in seed production at 700 seeds per stem. Seeds are dispersed by wind and birds.

Seedling

Root System

 

 

 

 

 

 

Spines

Flower

 

 

 

 

 

Currently there are 21 weeds on the Ohio Prohibited Noxious Weed List:

  • Shattercane (Sorghum bicolor) – February 8
  • Russian thistle (Salsola Kali var. tenuifolia) – February 22
  • Johnsongrass (Sorghum halepense L. (Pers.))
  • Wild parsnip (Pastinaca sativa)
  • Wild carrot (Queen Anne’s lace) (Daucus carota L.)
  • Oxeye daisy (Chrysanthermum leucanthemum var. pinnatifidum)
  • Wild mustard (Brassica kaber var. pinnatifida)
  • Grapevines: when growing in groups of one hundred or more and not pruned, sprayed,cultivated, or otherwise maintained for two consecutive years. – February 15
  • Canada thistle (Cirsium arvense L. (Scop.)) – March 29
  • Poison hemlock (Conium maculatum)
  • Cressleaf groundsel (Senecio glabellus)
  • Musk thistle (Carduus nutans)
  • Purple loosestrife (Lythrum salicaria)
  • Mile-A-Minute Weed (Polygonum perfoliatum) – March 7
  • Giant Hogweed (Heracleum mantegazzianum) – March 14
  • Apple of Peru (Nicandra physalodes) – February 28
  • Marestail (Conyza canadensis)
  • Kochia (Bassia scoparia)
  • Palmer amaranth (Amaranthus palmeri)
  • Kudzu (Pueraria montana var. lobata)
  • Japanese knotweed (Polygonum cuspidatum)

Each week, for the next 21 weeks, I will post information and pictures on how to identify these invasive and harmful plants.

Ohio Noxious Weed Identification – Week 7 Musk Thistle

Musk Thistle

Family: Composite, Asteraceae.

Habitat: Pastures, meadows, wasteland, and roadside ditches. Found sporadically throughout Ohio.

Life cycle: Biennial, forming a rosette the first year and producing flowers and seed in the second.

First Year Growth Habit: A basal rosette. Leaves are waxy and pale green with few hairs.

Second Year Growth Habit: Large, coarse, branched plant that can grow up to 9 feet.

Leaves: 3-6 inches long, alternate, spiny, deeply lobed, long and narrow.

Stem: Stems covered with dense, short hairs and spines.

FlowerJune – October. Purple thistle-like flower heads, 1-2” wide borne singly on stems; spiny-tipped bracts surrounding flower head. Often the flower heads droop or nod, hence the other common name of Nodding thistle.

Fruit: Seeds borne in white or tan feathery structures, similar to dandelion, spread by wind.

Similar plants: In the first year of growth, musk thistle may resemble bull thistle (Cirsium vulgare). However, the leaves of bull thistle are covered with hairs. Musk thistle is also referred to as nodding thistle.

The problem is….This prickly weed reduces the quality of grazing land. It has spread quickly throughout much of the Midwest, but is not yet common in Ohio. Avoid handling without gloves.

Seedling

Spines

 

 

 

 

 

Flower

Whole Plant

 

 

 

 

 

 

Currently there are 21 weeds on the Ohio Prohibited Noxious Weed List:

  • Shattercane (Sorghum bicolor) – February 8
  • Russian thistle (Salsola Kali var. tenuifolia) – February 22
  • Johnsongrass (Sorghum halepense L. (Pers.))
  • Wild parsnip (Pastinaca sativa)
  • Wild carrot (Queen Anne’s lace) (Daucus carota L.)
  • Oxeye daisy (Chrysanthermum leucanthemum var. pinnatifidum)
  • Wild mustard (Brassica kaber var. pinnatifida)
  • Grapevines: when growing in groups of one hundred or more and not pruned, sprayed,cultivated, or otherwise maintained for two consecutive years. – February 15
  • Canada thistle (Cirsium arvense L. (Scop.))
  • Poison hemlock (Conium maculatum)
  • Cressleaf groundsel (Senecio glabellus)
  • Musk thistle (Carduus nutans) – March 26
  • Purple loosestrife (Lythrum salicaria)
  • Mile-A-Minute Weed (Polygonum perfoliatum) – March 7
  • Giant Hogweed (Heracleum mantegazzianum) – March 14
  • Apple of Peru (Nicandra physalodes) – February 28
  • Marestail (Conyza canadensis)
  • Kochia (Bassia scoparia)
  • Palmer amaranth (Amaranthus palmeri)
  • Kudzu (Pueraria montana var. lobata)
  • Japanese knotweed (Polygonum cuspidatum)

Each week, for the next 21 weeks, I will post information and pictures on how to identify these invasive and harmful plants.