Currently, boxwood blight has not been confirmed in the state.  If you'd like to have the plants tested for boxwood blight, you can send in a sample to the Plant and Insect Diagnostic Clinic (provided it is not stone-cold dead - they cannot isolate pathogens from dead plant material).  
More information can be found here: 

• https://yardandgarden.extension.iastate.edu/pidc
• https://yardandgarden.extension.iastate.edu/how-to/how-create-holiday-wreath#disposal
• https://www.boxwoodhealth.org/knowledge-center

It is more likely that these boxwood suffered extensive winter injury.  Only a handful of boxwood species and cultivars perform well in Iowa - most available on the market across the country are not reliably winter hardy here in Iowa.  Even those that are winter hardy frequently see some winter damage, especially those newly planted in the fall.

When planting boxwood, species and cultivar selection is very important.  Korean boxwoods (Buxus microphylla var. koreana) can be used in Iowa with overall success. 'Wintergreen' and 'Winter Gem' have small, rounded, light green leaves. 'Green Mound,' 'Green Mountain,' and 'Green Velvet' are three hybrids that possess dark green foliage and grow about 3 feet tall.

Boxwoods perform best in moist, well-drained, neutral to slightly alkaline soils. They also require a sheltered location in Iowa. Boxwood foliage is susceptible to winter burn when subjected to strong winds or intense sun during the winter months. A location on the east side of a building is often a good site.

Boxwood are not good candidates for fall planting and if you plant in the fall, it should be early (mid-August through September)

Below are some resources that can help.

• https://yardandgarden.extension.iastate.edu/how-to/managing-winter-injury-boxwood
• https://yardandgarden.extension.iastate.edu/faq/how-do-i-prevent-desiccation-injury-my-yews-and-boxwoods
• https://yardandgarden.extension.iastate.edu/how-to/planting-late-summer-and-early-fall
• https://yardandgarden.extension.iastate.edu/how-to/how-care-newly-planted-trees-through-winter (this information on trees applies to shrubs as well)

Further questions can be directed to your local county Extension office. This local resource is very helpful since they are familiar with trends and issues in your part of the state. Click on this link to get connected directly with a staff person in your county Extension office and ask your gardening question. https://yardandgarden.extension.iastate.edu/ask-gardening-question