2017 journal article
Nutrient Sequestration by Vegetation in Bioretention Cells Receiving High Nutrient Loads
JOURNAL OF ENVIRONMENTAL ENGINEERING, 143(2).
Bioretention plant selection for nutrient removal (and even basic plant survival) is an understudied and not-well-understood component of this stormwater control measure. Twelve bioretention cells were constructed to evaluate 16 plants growing in three different media for their ability to remove nutrient pollution from urban stormwater runoff with high nutrient loads. Plants evaluated were pairs of natives and cultivars and included trees (Magnolia and Betula), shrubs (Viburnum and Itea), herbaceous perennial flowers (Helianthus and Eupatorium), a rush (Juncus), and an ornamental grass (Panicum). Eleven of the 16 species (B. nigra; B. Dura-Heat; M. virginiana; M. Sweet Thing; I. virginica; I. Henry’s Garnet; J. effusus; P. Shenandoah; H. angustifolius; H. First Light; and E. Gateway) performed well (grew and were aesthetically acceptable) in the bioretention cells and can be recommended as bioretention plants. Species and cultivar impacted the levels of remediation of the high N and P loads applied. The woody B. nigra and its cultivar stored the most N and P per specimen and per cost per unit canopy area. The herbaceous species P. virgatum and H. angustifolius sequestered the most N and P per unit area. However, if both low cost per nutrient uptake and high nutrient uptake per area are desired, then three species appear to be the optimal choices: P. virgatum; P. Shenandoah; and E. Gateway. The maximum nutrient mass any plant (B. Dura-Heat) accumulated in its dry biomass was nearly 11% of the inflow load.