The Prairie Patrol

Stranded, a purple coneflower stretches up from an unplowed slice of Minnesota grassland, signaling for help like a shipwrecked sailor on a desert island. Separated from its lifeline — a native prairie filled with plants and pollinators — it illustrates a widespread threat to the entire species.

This specimen arises with a few relatives from a remnant bound by railroad tracks and row crops. It is one of 27 study sites in Douglas County, Minnesota, evaluated each year by Stuart Wagenius, Ph.D., senior scientist at the Chicago Botanic Garden.

Although this plant may survive many more years, he says, it is unlikely to produce offspring due to its isolation. This is serious trouble for a species that relies on a habitat that has already dwindled to 1 percent of its original size. 

Prairie, says Dr. Wagenius, “is one of the most endangered habitats in the world. We want to learn as much about it as we can in part because the opportunity is fading, but also because there are opportunities for us to conserve it.”

Despite having been scraped by a snowplow the prior year, this roadside Echinacea angustifolia plant bore the most heads seen during a long-term study.
Despite having been scraped by a snowplow the prior year, this roadside plant bore the most heads seen during a long-term study.

His research focuses on Echinacea angustifolia, or narrow-leaved purple coneflower, a prominent prairie species native to Minnesota. Begun as his doctoral research project in 1996, it has since become a lifelong mission. He wants to create an improved habitat for existing plants, and increase the species’ ability to reproduce and thrive.  

Each year, he watches the plants on his study sites for damage from a triple-edged sword—pollination, genetic, and ecological issues.

The Pollination Puzzle
When the prairie stretched from horizon to horizon more than 100 years ago, Wagenius explains, a bee could have flown endlessly from flower to flower, carrying and delivering pollen. Are these insects still able to do their job?

Wagenius’s research has shown that the coneflowers continue to receive adequate visits from native bees. In fact, as he gave me a tour of his lab, he showed me an impressive collection of preserved sweat bees—small, emerald-green locals who have not succumbed to the plight of so many bees like the nonnative honey bees.

A native sweat bee collects pollen from a purple-leaved coneflower.
A native sweat bee collects pollen from a purple-leaved coneflower.

Instead, the problem is that the bees can only carry pollen so far. When they have few plants to work with in a small area, the pollen they deliver is not always accepted by the recipients.

The Genetic Glitch
After a few generations, Wagenius explains, all of the coneflowers in a small prairie become related, sharing pollen and some of the same genes. Then, if a bee delivers pollen with the same genes as the recipient plant, the pollen is likely to be rejected. In that case, no new seeds would be produced and no new generation of coneflowers would exist.

“Studying the genetics has offered some pretty good insight into what is going on in these small populations,” he says.

If related pollen is accepted, inbreeding can occur, which often results in weak offspring. Both issues diminish prospects for future generations.

Larger prairies are one potential solution to this problem. The other, Wagenius has found, lies right at his feet.

Wagenius and students discuss the discovery of a fly larva found eating pollen on a plant.
Wagenius and students discuss the discovery of a fly larva found eating pollen on a plant.

The Ecological Equation
In the past, natural fires on the land encouraged plants to flower, leading to new mating opportunities and refreshing local genetic diversity. Development meant the end of most of those fires. So, Wagenius and his team encourage trained land managers to restore fire through controlled burns.

When Wagenius returns to fieldwork this June, he plans to start with a blaze. He will conduct such a burn on a private landscape to increase the number of flowering plants and improve their chances of successful pollination and seed production.

A Family Affair
To begin fieldwork, he will meet on one of the larger study sites with his academic collaborators—including his wife Gretel, who is a botanist, and graduate and undergraduate students. His stay will be long enough that his other family members will join him there.

Researchers count leaves in a plot where 10,000 individual specimens were planted.
Researchers count leaves in a plot where 10,000 individual specimens were planted.

During fieldwork, he and his crew will measure the length and width of the leaves on each plant, and collect seeds that are later counted by Garden volunteers in a laboratory at the Daniel F. and Ada L. Rice Plant Conservation Science Center.

These characteristics help document the fitness of the plants. He will also compare the size of each preserve to the number of incompatible coneflower mates by studying the plants’ genetic patterns.

In addition, Wagenius will meet with local land managers and organizations to share advice on effective techniques. For example, he has suggested a controlled burn rather than plowing and replanting. “I’m glad to promote good conservation practices,” he says.

“I study habitat fragmentation and its consequences,” says Wagenius. Watch a video and learn more about his work.

Fortunately, many people would like to help him save the prairie, from duck hunters to farmers. “I’m in the role of not telling people to do more, but telling them how to do it better,” he explains. “I like being a person in our society helping others to do the right thing.”

This summer, a vision of hope rather than hopelessness will accompany Wagenius as he stands on the prairie with his research team and, well, a few relatives.

©2013 Chicago Botanic Garden and

Spring Lawn Care for Homeowners

With spring’s arrival, one can’t help but daydream about greener pastures, or in my case, lawns. Now is the time for spring lawn maintenance.

The main purpose of spring lawn care is to get the turf through the summer months. Cool-season grasses such as Kentucky bluegrass, perennial rye grass, and the fescues need to develop a strong root system to survive summer’s heat and dry conditions. There are a number of things you can do to ensure that your lawn gets off to a good start in the spring. Listed below are some things to do in April and May.

Spring Lawn Tips

Rake up debris from the lawn with a stiff metal rake.
Rake up debris from the lawn with a stiff metal rake.

1. Rake

Using a stiff metal leaf rake, go through your lawn and rake up any trash, debris, and fallen branches. This is a good time to asses your lawn to see if there has been any damage from the long winter months. Examples would be salt damage or dead spots, as well as any physical damage from animals or plows. Ideally, compost the leaves, stems, and other plant debris you rake up.

Core Aeration Machine
Aerating is by far the most important practice that you can do to help improve the quality of your lawn.

2. Aerate

Core aerating is the process of inserting hollow tines into the lawn and removing plugs of soil using specialized equipment. This practice will help reduce soil compaction and thatch. It also opens up the soil to let in nutrients and oxygen, and improves soil drainage. This practice should be done at least twice a year — once in the spring and again in the fall. If you can only do it once in a season, I would recommend early to mid-September.

Seed Spreader
A seed spreader works well for seeding large areas of lawn.

3. Seed

Once you get a chance to inspect your lawn, you may find a number of areas that need to be filled in. Inspect the area that you are going to work on and determine if it is in full sun, full shade, or a combination of the two. This is very important when choosing the correct type of grass seed to use in the area. When working in a full-sun area, a blend of Kentucky bluegrass and turf-type perennial rye grass works best. For a full-shade area, a fine-leaf fescue works best. If your area is a mixture of part shade and part sun, then you would want to go with a mixture of the three types of grasses.

Scratch up the area so that you get all of the debris off of the soil. You want to have exposure to bare soil. Sprinkle on a light-to-medium layer of seed over the top of the soil, and very lightly rake it into the top 1/4 inch. It is very important that the seed come in contact with the soil. Cover the seed with about 1/8 inch of a very fine compost or peat moss and water with a fine spray. You will need to make sure that the seed stays moist every day for about two weeks, or until the seed begins to germinate. Then you can slowly back off on the watering.  

PHOTO: an expanse of green turf grass.
Write down your lawn’s square footage so there’s no guesswork in fertilizer purchases.

4. Fertilize

Fertilization is a very important part of a lawn care routine, as it influences the color of the grass and its ability to recover from the stress of the long season, and helps prevent weed infestations and disease. There are some very important features to consider when you travel to your local garden center to buy your fertilizer.

Knowing the square footage of lawn that you have on your property will enable you to purchase the right amount of fertilizer for your home and prevent multiple trips to the garden center. Once you have figured out the square footage, write it down for future reference.

Nitrogen (N), phosphorus (P), and potassium (K) are the three major nutrients needed by your lawn. Nitrogen is the nutrient needed the most, although you do need to be careful because excess nitrogen can lead to abundant top growth and sometimes even kill the lawn if applied improperly.

On a bag of fertilizer you will see three numbers, such as “21-3-20.” The first number is nitrogen, the second is phosphorus, and the third is potassium. They are all in percent by weight. For example, the 21-3-20 fertilizer contains 21 percent nitrogen. This number is important because it determines how much fertilizer is needed. In most cases, a rate of 1 pound of nitrogen per 1,000 square feet is suggested for each fertilizer application to your lawn. Recommended ratios of N-P-K for lawn fertilizers include 3:1:2 or 4:1:2.

I recommend a controlled-release nitrogen source for your fertilizer, which would be indicated on the label of your fertilizer bag. With a slow release, you will see a more uniform grass growth. It is unlikely to burn the grass or cause losses through the soil and air.

I recommend at least three fertilizer applications per season for best results and to help out-compete most weeds.

PHOTO: mower blade height check.
Check the height of the mower blade with one wheel on a path to avoid cutting grass too short.

5. Mow

As soon as the grass needs cutting, mow it. Do not wait. Most cool-season grasses should be cut at a height of 3 to 3 1/2 inches in height. When you cut the grass at this height, it develops a thicker and denser stand of turf, and can out-compete most weeds. In addition, it will help conserve water by shading the bare soil and reducing evaporation during the heat of the day.

Always use sharp mower blades. I recommend sharpening the blades every week. Keep a spare blade on hand so that you can quickly change them out.

Don’t collect your grass clippings — let them fall back into the soil to decompose and add some nutrients back. Contrary to popular belief, they do not contribute to a thatch buildup in the lawn. Purchasing a set of mulching blades for your mower will help. They are available at most big box retailers.

With these few tips, you should be off and running to having the best lawn on the block. And remember, the grass is always greener in your yard.