Michigan’s Tick Explosion

Dermacentor variabilis American Dog Tick female

Female American Dog Tick

Michigan is undergoing a population explosion of Ticks.  Prior to this year, I had only seen one Tick in all my outdoor travels in Michigan. I have seen over a dozen Ticks so far this year. We are now finding them in our yard in Troy. Please watch out for ticks, especially if you care for children or outdoor pets.

The only species I have seen so far is the American Dog Tick (Dermacentor variabilis). For once, I’m hoping not to add other species to my list. Ticks are small, about the size of a sesame seed.

The State of Michigan has information regarding both the identification of ticks and the treatment of bites.

Dermacentor variabilis American Dog Tick male

Male American Dog Tick

Ticks are not insects but they are related to spiders. Hence, they have eight legs and not six as insects do. They are in the class Arachnida. I have seen them poised on the edge of a leaf waiting for a host to walk by. After jumping on to the host, they normally will move around for several hours before they bite. They embed their head and jaws under the host’s skin and feed on the host’s blood.

Copyright 2013 by Donald Drife

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Lawn Weeds

Anagallis arvensis Scarlet Pimpernel Flowers

Scarlet Pimpernel Flowers

Scarlet Pimpernel (Anagallis arvensis) also called Common Pimpernel is known from Michigan’s Lower Peninsula and is probably more widespread than records show. It is a member of the tropical Myrsine Family (Myrsinaceae) which contains about 1000 species in 35 genera. In Michigan the family has 13 species, not all native, in 3 genera. The flowers are red, blue, or white. The blue flowered type can be called Anagallis cerulea or Anagallis arvensis var. cerulea or Anagallis arvensis f. cerulea depending on whether you treat it as a distinct species, variety or form. Leaves of the red flowered type have their undersides covered with glandular dots. The blue flowered type lacks these glands. The flowers of all the color types open in the sunshine and close during cloudy weather giving it in the eastern U. S. the common name “Poor-man’s weatherglass.” It is a native of Europe, north Africa and west Asia. This is an annual species which is uncommon for most weed species. The red flowers, square stem, and glandular leaves make this an easy plant to identify.

Anagallis arvensis Scarlet Pimpernel leaves

Scarlet Pimpernel leaves


Salt Marsh Sand Spurry, (Spergularia marina) was first collected in Michigan in 1974 along a highway right-of-way.  It is native along the coasts of North America and grows at the edges of saltwater marshes. I found it for the first time along Maple Road in Troy, Michigan. It did not grow outside of the area that gets salt spray from the road. I did not know what it was but I was pretty sure that it was in the Pink Family (Caryophyllaceae). I ran it though the key in Voss and Reznicek (Field Manual of Michigan Flora). As often happens, once I identify a plant I find more colonies of it. I found it in Macomb Co. and also on the campus of Oakland University. Both of these colonies grow along sidewalks that are salted in the winter. The fleshy narrow leaves, five petaled pink flowers with three stamens, the salt loving habitat, and the short stature of the plant identify it. This species is also known by the newer name Spergularia salina.

Spergularia marina Salt Marsh Sand Spurry

Salt Marsh Sand Spurry


Stork’s Bill (Erodium cicutarium). This Mediterranean native was first found in Michigan in the early 1870s. It has become more common in the last decade and is now found throughout the state. I knew of a single station for this species in Oakland County in the 1970s. Now I know of dozens of locations. The seedpod gives the plant its common name. Erodium comes from the Greek word Erodios, which means heron. The entire plant can be used to produce a green dye. Stork’s Bill is identified by its sprawling habit, divided hairy leaves, and five-petaled pink flowers. (See Green Deane’s “Eat the Weeds” website for more info.)

Erodium cicutarium Stork’s Bill

Stork’s Bill flowers and seedpods

Copyright 2013 by Donald Drife

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Garlic Mustard (Alliaria petiolata) invading Michigan

Garlic Mustard’s (Alliaria petiolata) native range is Europe. It has invaded North Africa, India, and North America. The first U. S. record is from Long Island in 1868 and it reached Michigan in 1956. Imported for its supposed medicinal values it escaped cultivation and became a serious pest in many woodlands. I saw a large patch of it in 1978 in Rock Cut State Park in northern Illinois. Several acres in size this patch was shading out a colony of Prairie Trillium (Trillium recurvatum). I first saw the plant in Michigan at Warren Dunes State Park in 1981. It was a small patch consisting of a dozen plants. The plant has increased its range and is now found throughout the state.

Alliaria petiolata Garlic Mustard Plants

Garlic Mustard Plants

The plant is easy to identify. It is one to two feet tall (0.3-0.6m), the flowers are white with four petals that narrow at the base, and the leaves are heavily toothed, more or less triangular shape with the veins inset into the upper leaf surface. The seed pods are long and narrow with small ridges, and are similar to native species. They develop quickly, often elongating before the petals drop, and they will continue to develop after the plant is pulled.

Alliaria petiolata  Garlic Mustard Flowers

Garlic Mustard Flowers (note developing seedpods in right hand flowers)

It is a biennial, meaning that it flowers in its second growing season. The basal leaves form the first year and are more rounded than the stem leaves on the flowering plant. Garlic Mustard seed germinates at low temperatures (32 degrees F). This gives the seedlings a head start over other native species.

Alliaria petiolata  Garlic Mustard Basal Leaves

Garlic Mustard Basal Leaves

Garlic Mustard is allelopathic and destroys the connections between native tree seedlings and mycorrhizal fungi (Stinson K. A, Campbell S. A., Powell J. R. Callaway R. M. 2006). This prevents completion from native tree species and perhaps other plants.

Alliaria petiolata Garlic Mustard Leaves

Garlic Mustard Leaves

For additional reading regarding Garlic Mustard and its control, see the U. S. Forest service fact sheet.

Alliaria petiolata  Garlic Mustard Seedpods

Garlic Mustard Seedpods

Copyright 2013 by Donald Drife

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