This article was written by Emily Bowers, Minneapolis Park and Recreation Board Naturalist at North Mississippi Regional Park
Summer is a busy time in Minnesota, everything seems to be taking advantage of the increased sunlight and moisture this time of year provides. Plants diligently seize this opportunity to get a lot done as they grow, get pollinated and develop seeds in order to propagate. Spreading seeds can be a challenge though, when rooted in place. Since plants are unable to move their seeds themselves, they’ve developed other methods to have them dispersed.
A seed is a basic, but very important, part of any plant. After pollination, a seed begins developing inside a fruit, which can become a new plant if it finds the right conditions to grow. However if the seeds just fall to the ground under the parent plant, there would be too much competition for resources. So, plants have devised ways to get their seeds moving. The most common methods are wind, water and animals, but some are more extreme such as launching or fire survival. Additionally, to increase the chance that at least some seeds land in a suitable location, plants tend to produce a lot.
Seeds designed to ride the wind have shapes that make it easy to glide, spin or are light and fluffy. Maple tree seeds are built into a winged fruit, called a samara, with a flat propeller that spins like a helicopter to a new location. The elm tree has a round samara with papery edges to disperse by fluttering through the air. Basswood trees have a long, flat wing attached to the seed stem that spins it away like a wind-driven top. Fluffy seeds can burst off the head of a cattail, break up into a mass of parachutes from a dandelion, spill from a milkweed pod on silken strands or float in the breeze on a tuft of fluff from a cottonwood. With wind dispersal, seeds are simply blown about and land in all kinds of places.
Some plants, such as willow trees, will utilize wind as well as water to carry their light fluffy seeds to new shores. Seeds that move via water are buoyant or able to stay on the water’s surface to float away from the parent plant. Jewelweed, or touch-me-not, relies on a dispersal method that’s not quite so gentle. Its seedpods explode when touched, using a ballistic mechanism to launch the seeds like a catapult some distance from the parent. Another tough love tactic used by some pine species is to make seed pods not just fire resistant, but actually require the heat from a fire before their cones will open and release seeds. This creates a scenario where most other competition has been destroyed, leaving plentiful resources for the seedlings.
The development of a good tasting, fleshy fruit is a great trick plants use to attract animals to eat their seeds and spread them around. A seed may be spit out or dropped after the fruit has been eaten or deposited out the other end amongst a pile of fertilizer. In fact, certain seeds need to be digested in order to wear down the hard seed coat, break dormancy and be able to sprout, such as with cherries and blackberries. Animals like squirrels and chipmunks collect seeds and cache them away for later. Squirrels famously misplace their buried acorns, which then have an excellent chance of germinating. However, more viable seeds are dispersed than just those forgotten. Interestingly, the part of the seed that sprouts is at the bottom of the acorn, which is also more bitter and often discarded by squirrels. This symbiotic relationship keeps squirrels fed and oak trees growing. Squirrels aren’t the only critters that like acorns though, birds such as wood ducks, wild turkeys and jays can also be caught eating them as well as raccoons and deer. Animals assist in spreading plant seeds in a much less pleasant way too. Some plants have seeds with hooks, barbs, spurs and burs that become easily stuck to fur, feathers or human clothes and go unnoticed until they are far away from the parent plant.
This summer enjoy the outdoors through drop in discovery in your community! Naturalists will ’round up’ fun, interesting and inspiring nature activities for you safely at a neighborhood park! Join us for no-touch or easily sanitizable nature exploring — topics may include planting seeds, meeting live animals, dissecting an owl pellet, playing water quality mini-golf, and much more! Tuesdays from 4-6 p.m.: Aug. 4 at Beltrami; Aug. 11 at Creekview; and Aug. 25 at JD Rivers Children’s Garden. No need to register, just stop by for free family fun!
Get outside and into Nearby Nature, with self-directed, nature-based activities designed to enhance the experience of park goers of all ages while exploring parks. All Nearby Nature activities are free and no registration is necessary. Just show up and be ready for fun, relaxation and inspiration! North area parks include: North Mississippi Regional, Creekview, Bohanon, Victory, Cleveland, Perkins Hill, Jordan, Willard, Hall, Farwell, Bethune and Bryn Mawr Meadows. Get activity locations each week at the Minneapolis Parks Neighborhood Naturalist page on Facebook. Share experiences and photos through the hashtag #NearbyNatureMpls or send feedback to our email nearbynature@minneapolisparks.org. Visit the Kroening Interpretive Center Facebook page for more fun ways to connect with nature in our community.
Youth and teens ages 8 to 18 are invited to get creative by joining in a week of kit-based artmaking from home, connecting with an artist and other young creatives. Sign up for a Minneapolis Institute of Art Virtual Artist in Residence (AiR): Beltrami Park on Aug. 3-7, activity #108851; and Whittier Park on Aug. 17-21, activity #108852.
Minneapolis Park and Recreation Board program buildings remain closed to the public until further notice due to the impacts of COVID-19. The MPRB’s priority is the health and safety of our park visitors and our employees. Visit minneapolisparks.org/coronavirus or sign up to receive email updates at minneapolisparks.org/subscribe by selecting “COVID-19” in the “News Updates” section.
Do you have a question about nature in your own backyard? Then send it our way by emailing northmississippi@minneapolisparks.org and it could appear in a future article.