The How and Why of Plant Selection for BMPs: A Hydrologist’s Perspective Scott Dierks, PE

1. The How and Why of Plant Selection for BMPs: A Hydrologist’s PerspectiveScott Dierks, PE June 13, 2013

2. Talk Outline • Why discuss plants? Aren’t they just decoration? • Refuting the notion plants are just “add-ons” • Starting with how we do things, and moving to: • How a complete ecological system does things • Understanding plants as design elements • Selecting plants • Seeding, planting & maintenance

4. How We Do Things • Est. total paved area in the US = 43,480 square miles = 5.5 x the size of New Jersey • In 1900 60% of Americans lived in rural areas (USDA estimate). • In 2005 83% of Americans live in urban/suburban areas. • By 1986 over 69 million acres converted to urban/suburban landscapes (53x the size of Delaware) • 30-40 million acres (62,500 mi2) in suburban lawn • Over 4 million miles of paved, public roads

5. Source: Stu Schwartz, Univ. of Maryland at Baltimore

8. Impacts of “Soil Abuse”

9. How Plants Do Things • There is a feedback loop between biotic & abiotic components of soil. • Plant roots & bacteria release secretions that bind inorganic soil together into aggregates • Exudates fuel biological activity, such as nutrient and pollutant cycling. • Micro-aggregates are also bound together by root hairs, roots and fungal hyphae • Changes in pore size distribution are made by roots, burrowing animals and dying roots

10. X-ray Computed Tomography of upper soil column

11. Comparison of 24 side by side studies of cultivated land – row crop, pasture and turf grass vs un-cultivated land – ag buffers, restored and remnant prairies and forests • Same taxonomic soil series for each paired study • Data for A/B soil horizons for approximately 0-12-in depth

12. Aerenchyma

13. Understanding Plants as Design Elements

14. What is the target hydrology?

15. Water Balance Modeling

16. (1985)

17. Determine hydroperiod/innundation/drawdown time

21. Source: www.semcog.org/LowImpactDevelopment.aspx. Source: www.semcog.org/LowImpactDevelopment.aspx.

25. These plants are tolerant of fluctuating water levels in this range. They will tolerate short periods of innundation, not to exceed 48 hours.

27. Planting Recommendations • Diversity is relative to the size of the BMP • < 200 Sq. Ft. - 5 species • 200 Sq. Ft. – 1500 Sq. Ft. = 6 – 9 species • 1,500 Sq. Ft. - 10 – 20 species • Landscaped appearance – 3 ft. O.C. • Naturalized appearance – 1 ft. – 2 ft. O. C. • How to calculate the number of plants: • A/D² = # of plants • Where A = planting area in square feet • Where D = distance between plants on center (feet) Example: A 500 sq.ft. rain garden planted with plugs at 2 feet O.C. 500/2² = 125 plants

28. Developing a Planting Plan • Plant groups – submerged, emergent, mesic, upland • Consider height of mature plants • - Plant taller species toward back • Plant species that are adapted to the specific environmental factors • - Determine hydroperiod/innundation/drawdown • - Is the site sunny or shady? • - Are portions of the site exposed to salt spray/runoff? • Select plants that bloom at different times and/or different colors • Mass similar plants – helps with growth and aesthetics

29. Seed • Make sure you get Pure Live Seed (PLS) • Can cover large areas more efficiently • Usually includes a cover crop – annual oat or rye • Slower to establish 2 -3 years • Often combined with plugs or gallon stock • Sold as mixes or can custom order • $700 - $1300 per acre • You lose control of what species get planted and exactly where they go • Typically do not seed permanently innundated areas

30. Plants • Plugs • 2.25” x 5” • From $1 - $3.50 per plug • Installs quickly • Faster start than seed • Gallon containers • $4 - $6 per gallon • Older than plug plants • Faster establishment than plugs

31. Trees and Shrubs • 5 gallon size - $18 -$25 each • Ball and Burlap 4 ft – 6 ft - $60 - $80 each • Ball and Burlap 2 in diameter at breast height (dbh) - $100 - $300

32. Maintenance • Even landscapes planted with natives require some maintenance, particularly for the first two years after planting. • Invasives are typically primed to invade disturbed sites, hence the need for early vigilance. • Typically first-year’s maintenance is built into the installation contract with a guarantee to meet a threshold survival criteria, e.g., 80% coverage • Hand-pulling, targeted spraying, mowing before invasives go to seed and prescribed burning are excellent ways to fight invasives and foster native plant growth • http://chesapeakestormwater.net/training-library/design-adaptations/stormwater-bmp-maintenance/ • http://www.stormh2o.com/SW/Articles/Maintenance_of_Stormwater_BMPs_3287.aspx • http://rfcd.pima.gov/pdd/lid/pdfs/41-wa-spu02-020023.pdf

33. Other Plant Selection Resources WHAT TO PLANT Indiana Native Plant and Wildflower Society (INPAWS): http://www.inpaws.org/ Indiana Wildlife Federation – Native Plants of Indiana: http://www.indianawildlife.org/wildlife/native-plants/ Porter County Landscaping Standards and Guidelines, Recommended Plant Lists: http://www2.porterco.org/uploads/media/Section_19_-_Appendix_01.pdf CardnoJFNew Nursery http://www.cardnojfnew.com/Nursery.aspx WHAT NOT TO PLANT! Indiana’s Most Wanted List (Purdue University): http://extension.entm.purdue.edu/CAPS/browsePest.html

34. How we could do things better together Source: San Mateo County Sustainable Green Streets and Parking Lot Guidebook

35. Questions? Scott.Dierks@cardno.com