Marietta Sand Prairie State Preserve

Marietta Sand Prairie is a 17-acre preserve featuring aeolian (windblown) sand deposits and a sand prairie. It is located seven miles northwest of Marshalltown in Marshall County. The area was purchased in 1983 from the Conrad family by a lifelong Marshall County resident who wanted to give a lasting gift to the county. The prairie, initially named “Conrad Sand Prairie,” was renamed “Marietta Sand Prairie” after the township in which it is located. The area was dedicated as a biological and geological state preserve in 1984.

About the Land

Located along the northern edge of the Southern Iowa Drift Plain landform region, this upland sand prairie was created when strong winds blew sand to here from abundant sources in the nearby Iowa River valley. The sand had originally been deposited in the valley following the melting of the Des Moines Lobe glacier about 12,000 years ago. This sand was then picked up from the valley bottoms by the wind and redeposited on the nearby uplands. These aeolian sands are up to thirty-six feet deep in places and form an unusual habitat where sand-loving prairie plants prosper.

The majority of the prairie is dry upland prairie, which grades into soggy sedge meadow at the base of a hill. A moist woodland is also present on the property.

Directions

1. From the intersection of Highway 30 and Highway 330 west of Marshalltown, take Highway 330 north to 190th Street.
2. Go west (left) 2 miles on 190th Street and turn north (right) onto Knapp Avenue (sign: Marietta Sand Prairie Preserve).
3. Go 1.25 miles to the preserve on the east side of the road (sign: Marietta Sand Prairie Preserve).

Plants

The variety of habitats found here supports nearly 200 species of plants. In April, an abundance of hairy puccoon can be seen, along with golden alexanders and marsh marigolds.

In the upland prairie, later blooms include:

• Sand milkweed
• Green milkweed
• Wild four-o’clock
• Spotted horsemint
• Sand primrose
• Shaggy false gromwell, and 
• Purple lovegrass

In the wet meadow, marsh bellflower, marsh St. John’s wort, great lobelia, and marsh fern can be seen blooming during the summer. 

As fall approaches, the yellow blossoms of partridge pea, prairie sunflower, and several goldenrods can be found among the bobbing heads of round-headed bush clover and the silvery leaves of white sage in the upland prairie. 

The wetter habitats contain the purple hues of panicled aster and bottle gentian.

Birds & Species

The preserve provides a habitat for a number of birds, including song and field sparrows. Common snipe and American woodcock can also be seen displaying over the open sandy prairie in the spring. 

The loose, sandy soil provides habitat for Plains pocket gophers, as well as badgers that prey on the pocket gophers. 

Visitor Information

Other public areas in the vicinity include Hendrickson Marsh and Wehrman Prairie.