Poisonous plants in Iowa can be found among the natural bounty of the region. All gardeners, natives, and hikers must familiarize themselves with these plants to ensure safety, because different plants and their saps can have an altering results on everyone.

Dangerous and Poisonous Plants in Iowa

This post contains a description of the most prevalent poisonous plants encountered in Iowa. Keep reading about each plant and their descriptions right here.

List of Poisonous Plants in Iowa

1. Poison Hemlock

Growing Season All year round
Leaf Shape Triangular
Specific Needs
  • Moist soil
  • Part or full sunlight
Common Pests Aphids

Poison hemlock is a highly toxic plant native to Europe, Northern Africa, and Western Asia that has become naturalized throughout many parts of North America including the state of Iowa. What you need to keep in mind is that all parts of this biennial member of the carrot family are toxic if ingested, and this is one of them.

The Deadly Conium Maculatum

Some symptoms would include dilated pupils, profound weakness, coma, and death due to respiratory failure. As a precautionary measure, the poison hemlock should not be planted in residential areas or grazed by cattle and other livestock, and care should be taken when weeding in Iowa fields and roadsides. One must be cautious and mindful about such a poisonous plant, in order to stay safe and away.

2. Stinging Nettle

Growing Season
  • Fall
  • Spring
Leaf Shape Heart-shaped
Specific Needs
  • Part shade or full sunlight
  • Moist nutrient-rich soil
Common Pests
  • Hoverflies
  • Lacewings
  • Parasitic wasps

Stinging nettles are herbaceous perennial flowering plants found throughout Iowa and other states, too. This plant can grow up to five feet tall and bears clusters of small yellow-green flowers. Its primary feature is its stinging hairs, which contain formic acid and histamine, and would cause harm.

The Painful Urtica Dioica

These can cause severe skin irritation upon contact with the stems or foliage of the plant. Some precautions must be taken when harvesting stinging nettle due to the possibility of getting pricked by its irritant components, one of which would be to avoid touching it unless you are weakening a pair of well protected gloves.

3. Wild Parsnip

Growing Season Summer
Leaf Shape Diamond-like shape
Specific Needs
  • Moist soil
  • Partial or full sunlight
Common Pests Parsnip webworm

Wild parsnip is a perennial, poisonous plant found in many parts of Iowa. It has yellow flowers that form umbels and have five to seven petals with jagged edges. The stem and leaves are covered in tiny bristles that can cause skin irritation when touched by humans it would also effect animals the same way.

Harmful and Wild Pastinaca Sativa

The sap from the plant contains phototoxic compounds which cause blisters and bumps on the skin as it would be exposed to sunlight. Overall, remember that wild parsnip often grows in disturbed areas such as along roadsides and abandoned fields, so they should be avoided at all costs.

4. Poison Ivy

Growing Season
  • Spring
  • Summer
Leaf Shape Rounded
Specific Needs
  • Moist but well-drained soil
  • Partial shade or full sunlight
Common Pests
  • Beetles
  • Flies

Poison ivy or Toxicodendron Radicans is a poisonous plant that is commonly found throughout Iowa and other parts of the United States. This perennial shrub grows in a variety of habitats, from woodlands and open fields to riverbanks and ravines.

Infamous Rhus Radicans

When disturbed, this plant will release an oil called urushiol which causes an itchy and potentially painful rash on exposed skin, and this could last for some days, but it would also depend on how big the quantity is, as a result of the latter, all contact with the leaves, stem, or rootstock of this plant should be avoided. However, it is possible to come into contact with poison ivy indirectly.

5. Poison Oak

Growing Season Spring
Leaf Shape Rounded/irregular
Specific Needs
  • Full sunlight
  • Moist soil
Common Pests
  • Spider mites
  • Whiteflies

Native to the eastern and western United States, poison oak is an evergreen shrub or vine that produces an irritating sap containing urushiol, a toxin found in many other poisonous plants, however, in this plant, it is quite in abundant levels. In the state of Iowa, this plant is most commonly found along trails and waterways, usually having dense thickets.

Toxicodendron Diversilobum Plant

It has round-toothed leaves that can be shiny green or red depending on the season, as well as clusters of small white berries. Victims may experience a red rash and intense itching if contacted by sap from poison oak’s leaves or stems. On another note, you shouldn’t even consume any part of this plant either, because when done as such, it can be severe enough to even kill a person.

6. Velvetleaf

Growing Season
  • Summer
  • Fall
Leaf Shape Heart-shaped
Specific Needs
  • Loamy soil with average moisture
  • Full sun
Common Pests
  • Tobacco budworm
  • Bollworm

Velvetleaf is a toxic plant species that has become increasingly problematic in Iowa, where it is classified as a noxious weed. This member of the Malvaceae family can reach heights of up to five feet.

Pernicious Abutilon Theophrasti

It produces a large number of yellow flowers during warmer months and prolific seed pods which readily spread the problem throughout agricultural fields. Velvetleaf appears to primarily poison livestock who consume it, resulting in severe digestive symptoms such as decreased appetite and reduced milk production.

7. Virginia Creeper

Growing Season Summer
Leaf Shape Elliptical
Specific Needs
  • Moist well-drained soil
  • Full sunlight to shade
Common Pests
  • Flea beetles
  • Leafhoppers
  • Leafcutting bees

Virginia creeper is a poisonous plant native to Iowa, recognizable by its five leaflets arranged in an alternate pattern on the stem. While it does produce attractive blue-black berries, all parts of this vine contain oxalic acid and other glycosides that cause nausea and vomiting should they be ingested, it would intoxicate the human stomach as the latter would not be able to digest it properly. 

Invasive Parthenocissus Quinquefolia

Moreover, its sap can cause dermatologic irritation when in contact with the skin. Given these effects, it is advised that individuals take precautions when spending time outdoors near planted areas where Virginia creeper grows.

8. Climbing Bittersweet

Growing Season
  • Spring
  • Fall
Leaf Shape Oblong
Specific Needs
  • Constantly moist organically rich soil
  • Increased exposure to the sun
Common Pests
  • Spider mites
  • Aphids

Climbing bittersweet is a deciduous, woody vine that is native to Iowa and typically found along streams and in some southern forested areas. This plant has a vining stem that would twine around nearby trees and shrubs with the help of tendrils from opposite sides of each leaf, although it would look quite nice, but as opposed to its beauty, it is intoxicating.

Destructive Celastrus Scandens

However, it can become invasive due to its ability to outgrow native vegetation making it difficult to control. The plant’s berries are also toxic to humans, which means that it is best when caution has been taken when handling them.

9. Belladonna Lily

Growing Season Spring
Leaf Shape
  • Narrow
  • Strap
Specific Needs
  • Well-draining soil
  • Full sun
Common Pests
  • Red spider mite
  • Slugs
  • Snails

The Belladonna lily or Amaryllis Belladonna is an extremely toxic plant that grows wild in Iowa and is generally considered to be one of the most poisonous plants in the state. It features large pink-and-white flowers and can reach heights of up to eighteen inches tall.

Deadly Amaryllis Belladonna

All parts of the plant are highly toxic and can cause severe reactions if ingested, including abdominal pain and vomiting, cardiovascular abnormalities, visual disturbances, drowsiness or confusion, seizures, rapid breathing, and even death if it is not treated timely. Even when an animal eats it, the sap would intoxicate them too. 

10. Spurge Laurel

Growing Season All year round
Leaf Shape Oblong
Specific Needs
  • Full sunlight to partial shade
  • Humus-rich soil
Common Pests Aphids

Spurge laurel or Daphne Laureola can be found in woodland areas across Iowa and is a highly poisonous, evergreen shrub that should be approached with caution. It has a characteristic of growing up to three feet in height, the foliage has a glossy texture and glabrous vinous leaves.

The Harmful Daphne Laureola

Its inconspicuous yellow-green flowers appear from April to June and its purple-black berries can remain into midwinter, although they would look nice, but the plant, wholly is intoxicating. Although it may have some ornamental value due to its hardiness, Spurge Laurel can be toxic when ingested or when the sap contacts broken skin irritating the mucous membranes and ulceration the skin.

Conclusion

This list of poisonous plants in Iowa has shown you how dangerous these plants can be. Here are some of the significant dangers at a glance,

  • Wild parsnip can cause blisters and bumps on the skin.
  • Poison ivy causes an itchy and potentially painful rash on exposed skin.
  • Poison oak can cause a red rash and intense itching.
  • Virginia creeper causes dermatologic irritation when in contact with the skin.

If you want to keep yourself safe from these problems, you should avoid coming into contact with the plants we have described here.

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