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March Article

Storm Water, Rain Gardens, and Native Plants

"Storm water" sounds pretty technical, but it can be simply defined as water that runs off of hard surfaces like roads, driveways, and rooftops. Along the way, this water picks up and carries pollutants like nutrients, heavy metals, oils, and other compounds. Eventually, this storm water finds its way into storm sewers that drain into our favorite urban creeks, wetlands, and lakes. Over time, these pollutants can accumulate and cause adverse effects on aquatic systems.

In Minnesota, cities, counties, and watershed districts are in charge of managing storm water. One of the most popular ways to reduce and treat storm water is by creating rain gardens. Rain gardens are just engineered low spots in the landscape that trap and infiltrate storm water. 

Some consider rain gardens as natural filters that help to clean water. Every rain garden helps to reduce pollutant loads and preserve and improve our aquatic systems. Cumulatively, they can make a big difference. 

Some of the most effective rain gardens are designed to treat road runoff. A common method involves strategically cutting a section of curb out of the roadside, and allowing water to flow off the road and into constructed garden areas. An average "curb cut" rain garden is able to treat thousands of gallons of water each year.


To live up to their name, a majority of the rain "gardens" in Minnesota use plants to help in the filtration process. So how do plants play a key role? And what happens to the pollutants that end up in the rain gardens? 

A large percentage of the nutrients in storm water are absorbed and retained by the plants. For instance, native plants are able to absorb dissolved phosphorus, ammonium, and nitrates. Research has shown that some plant species are better than others at using nutrients in the storm water. For example, dogwood , Joe-Pye weed, sunflower, and Blue flag iris are great at absorbing nutrients. Plus, they are able to handle both wet and dry periods. Of course, plants only absorb the nutrients during the growing season, making nutrient uptake during winter less effective. 

Also, once the plants die back each year those nutrients can be released as they decay. It is a good strategy to remove the old vegetation before it decays so the nutrients are better managed.

Heavy metals come from industrial, manufacturing, and transportation activities. These metals can be attached to soil particles or dissolved into the storm water. Plants growing in rain gardens can actually accumulate metals into their tissues (LeFevre et al., 2014). Some plants are more efficient at doing this than others. Species that are especially good at absorbing metals are called hyper-accumulators (Salt et al. 1998). 

Plants can also uptake organic pollutants like hydrocarbons (from oil leaks, emissions, grease, and tire particles). Plants house microorganisms in their roots that also help break down contaminants. Their roots also aerate the soil, increasing levels of oxygen that encourages aerobic chemical breakdown. 

Rain gardens can greatly benefit Minnesota's waters. They can be especially important in urban landscapes where we try to blend development with environmental responsibility. Their main purpose is to intercept the storm water before it runs into our creeks and lakes; however, well designed rain gardens can also look great and provide food and habitat for pollinators. Native plants are essential for our pollinators, and play an important role in water quality. 

Interested in learning more or about installing your own raingarden? Contact us and we can help get you started! 


Native Plant of the Month
Jacob's Ladder  
Polemonium reptans

Moisture: Moist
Exposure: Shade or Partial Sun
Bloom: April-June
Color: Blue
Height: 10-20 inches

Jacob's Ladder is a small plant with delicate blue, bell-shaped flowers. The flowers have five petals. The leaves are compound with leaflets that climb up the leaf stem like rungs in a ladder. Their stems are smooth that go into a deep taproot.  It grows best in moist, rich soils and is often found in woodlands and semi shaded areas along rivers.  Their flowers are visited by bees, butterflies, and moths.  Jacob's Ladder mostly spreads by seeds. Native Americans used to use the roots for medicine. The common name is derived from the biblical tale of Jacob's dream of a ladder or a stairway to heaven.  Other common names are Greek valerian and creeping Jacobs ladder.  
Invasive Plant of the Month


2002  © Peter M. Dzuik

Nepeta cataria


Exposure: Sun or Shade

Moisture: Dry or Moist

Height: 1-4 feet

Blooms: July- October


A weedy perennial from Europe, it is often planted in gardens for use in tea and for entertaining cats. Catmint has a square stem. Their small tubular flowers are white or lavender with darker purple dots. They are arranged in a 2-4 inch cluster on the top of the stem. Leaves are light green and very hairy. They are about 2 inches long and 2 inches wide with rounded teeth. It is also known as catnip and can be found in many varieties. Management strategies include hand pulling, dead-heading the flowers to prevent seeding, or herbicide treatments. 

Pollinator of the Month

Paper Wasp

Polistes spp.


Range: Throughout North America

Habitat: Open areas, meadows, road sides

Identification: Light brown wings and legs. Thin torso. Body alternating with black and white markings

Pollination: Paper wasps visit many different species of flowers to collect nectar. Some examples of native plants they visit are Heath Aster, Butterfly Milkweed, Swamp Milkweed, Rattlesnake Master, Golden Alexander, Zigzag Goldenrod, and other native plants. 


Paper wasps make the small, papery comb nests that we commonly see on buildings.  They can act aggressively to protect their nests when provoked. However, they are quite docile while visiting flowers to collect nectar for carbohydrates. They also are predators and used for biological control for some problem insects. 

March 2015 Issue
Our Company
Retail Nursery News
Our Retail Nursery is closed for the season. Check our website for next year's retail dates and other updates.

Click and visit our website for current
Minnnesota Native Plant Brand ensures that plant species are native to Minnesota. 
Upcoming Events

The 12th annual Spring Days Gardening Workshop and Expo is being held again Saturday March 7th at the St. Michael-Albertville Middle School West. Come Join us!

Join us again for the 5th Annual Shorewood Spring Garden Fair! March 14th 8:30am-3pm 5735 Country Club Rd. Own own installation manager Joe Ackerman will be presenting about native plants!

The annual Minnesota Native Plant Society Symposium is March 21st! Come visit our booth to learn more about native plants!

We will also be at the  2015 Annual Horticulture Education Day Sat. March 28th 8am-3pm at the Crow River Golf Club at 915 Colorado St. NW, Hutchinson MN. Come visit!
Plymouth Yard and Garden Logo
Visit us Friday April 10th from 6pm-9pm and Saturday the 11th  9am- 1pm for the Plymouth Yard and Garden Expo at the Plymouth Creek Center!