Common Mullein at Jacob Krumm Preserve

A hawk circles the savanna on Feb 1, 2017

Recently I headed out to the Jacob Krumm preserve in between Grinnell and Kellogg, Iowa. It's a 450 acres of land that was converted from row crop agriculture into tallgrass prairie and savanna (1). It has 7 miles of trails for outdoor enthusiasts (1).

Along the way, I came across white-tailed deer, hawks, crows, and the standing remains of plants from the previous year. Some still had seed heads attached, but most had blown down to stems, branches, and blades of grass. However, I came across one plant greening up in the abnormally warm winter. I thought perhaps it might have been the skunk cabbage which uses a high metabolism to warm the soil in winter time so that it can leaf out and bloom far earlier than most other plants. Upon researching , I found this not to be true. Instead, I believe I've stumbled upon the early growing rosette of the Common Mullein (Verbascum thapsus).

Mystery plant (Common Mullein) close-up. What plant starts growing in February in Iowa?

The mystery plant (V. thapsus) with my hand for scale

V. thapsus is an invasive plant from Europe and Africa that was brought over in the 1700s (3). It's a biennial which means that it grows leaves for one year, winters, and then grows a flower stalk the next year before dying*. It can be used in herbal remedies (2, 3). As always, be careful when making your own concoctions from wild plants. The wrong identification or preparation could lead to lethal poisoning and other serious side effects.

This particular plant was found on the side of a dirt trail, which is not surprising. Most invasives gain a foothold into an area through disturbances such as road building, migrating animals, fires, etc. that leave openings in the native vegetation. Invasive species then out compete native species by reproducing in large quantities, limiting light and other nutrients, or taking up limited habitat space (4).

Because Iowa has been so transformed by human activity, invasive species have lots of opportunity to enter remaining natural spaces. It can be difficult to keep track of which plants are native, non-native, and invasive. Because these natural refuges are important, it's up to all of us to maintain them.

Landscape of the February Prairie at Jacob Krumm Preserve in Grinnell, IA Feb. 1, 2017

Close up of a native grass seed head

*Many biennials don't adhere strictly to a two year schedule, but more like a two stage cycle wherein they could spend years in the rosette stage until the right environmental factors trigger the change to a flower stage, after which the plant dies. There's still a mystery as to why this happens and what exactly triggers the switch. But for the most part, this life cycle takes two years on average.


References:
(1) http://www.mycountyparks.com/County/Jasper/Park/Jacob-Krumm-Nature-Preserve-East.aspx
(2) Swearingen, J., C. Bargeron. 2016 Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health. http://www.invasiveplantatlas.org/
(3) http://www.livescience.com/52001-common-mullein-herb-plant-photos.html
(4) https://www.fws.gov/invasives/faq.html#q4