Photo by Shaw Nature Reserve.
Photo by Bruce Schuette.
Native Plant Roots Come in all Shapes, Sizes, and Depths
Pale purple coneflower (Echinacea pallida) at Penn. A total of 289 plant species have been recorded at the Missouri Prairie Foundation’s 160-acre, original, unplowed Penn-Sylvania Prairie in Dade County, MO. In July 2018, botanists identified 46 native species in a 20 x 20 inch frame, setting a new world record for plant richness at this scale.
T
o say that native plants have deep roots is like saying all Italians are great cooks, all goldfish are gold, and all cats are white with black spots. These statements are sometimes true, but definitely not always. Plants on earth have evolved and adapted to grow in almost every environment and soil type. To do this, they have diverse root anatomies. Some roots are fine, dense, and shallow (sedges and azalea, for instance), others are coarse—like jump ropes—spreading out wide
(like wild indigo and redbud), and yet others grow like a carrot, with a trunk that shoots straight down as far as it can go (e.g., prairie dock and compass plant). I think the misconception that native plants have deep roots stems from studies that came out of the tallgrass prairie region where plant roots were excavated to a depth of 10 feet or more. In many areas of the Midwest, prairie soil is very deep, the result of ten thousand years of plant growth cycles, where roots expanded during periods
SCOTT WOODBURY Horticulturist 14
October 2020 | kcgmag.com
of optimal growth and died back slightly during periods of flood or drought. These cycles distributed organic matter (compost) deep in the soil column, generating rich, fertile soils throughout the heart of the tallgrass prairie region. Today it grows the richest corn and soybean crops in the world. A more accurate way to look at native plant roots (or for that matter, roots of plants anywhere) would be to think of each species as being vertically and horizontally territorial underground. For example, there
The root of a 15-year-old compass plant (Silphium laciniatum), dug from Shaw Nature Reserve with a back hoe. are many species living closely together in ancient remnant tallgrass prairies (miraculously some still exist). For example, the Missouri Prairie Foundation’s Penn-Sylvania Prairie holds the world record for plant diversity on a fine scale, with 46 native species documented within a 20 by 20 inch frame. One reason that they can live so close together is that each species is vertically segregated. Some species grow deep (culver’s root and leadplant); some lie shallow at the surface (strawberry and pussy-
Horticulturist Scott Woodbury is the Curator of the Whitmore Wildflower Garden at Shaw Nature Reserve in Gray Summit, MO, where he has worked with native plant propagation, design, and education for 28 years, and which is supported by the Missouri Dept. of Conservation. He also is an advisor to the Missouri Prairie Foundation’s Grow Native! program.
