Multiple variables considered for new, successful, pollinator-friendly plantingsWritten by Natasha Wheeler
“Pollinator habitat and pollinator plants mean a lot of different things to different people,” notes USDA Natural Resources Conservation Center (NRCS) Plant Materials Center (PMC) Manager and Horticulturist Joe Scianna.
From a small pot in the backyard to whole fields, plants can be grown to attract pollinators throughout the season.
“For those who are thinking in terms of home landscape, we can do this with plants, or we can do it with seeds,” he mentions.
At the NRCS Plant Material Center (PMC) office in Bridger, Mont., the research team adapted a section of land between two sidewalks that was filled with Kentucky bluegrass, various weeds and other plants.
“We thought it might be nice to have a combination of a rain garden and a pollinator planting out front,” he explains. “We propagated our own plants, which homeowners can do, as well.”
At PMC, the team first implemented vigorous weed control a few years before planting, laid down a wood-fiber mat to retain soil moisture and introduced their new plants to the soil.
“All of our plants are natives. We still have some weeds, so we spot-spray with a little Roundup and we hand pull. It’s really quite self-sustaining,” he says.
The plot contains a wide variety of plants, including native yarrow, black-eyed Susans and prairie comb flower.
“The other thing to note is that we put in some grasses. We like bunch grasses. We like the way they look. We also like their stature, and it adds a little variety,” he continues.
Grasses can be tricky though, as rhizomatous grasses – grasses with horizontal root structures – can spread out easily.
PMC considers plot-sized areas of land as anything ranging from five-hundredths of an acre to a tenth of an acre.
“We’re probably moving toward seeding when we get to this size,” notes Scianna.
Broadcast seeding is one option, or growers can use a planter to drill seed.
“This is kind of an in-between size. Because it’s almost exclusively done with seed, we now get into more decision making about how this is going to work, what species we’ll use, how well they work together, what time of year we plant, how many seeds to put out and those kinds of things,” he describes.
There are a number of important considerations when creating pollinator-friendly plantings, including plan design.
“We don’t want to just go get seed and throw it out there,” warns Scianna. “We want to know what our goals are. If we want a pollinator habitat, that’s pretty simple, but a lot of times, we think about other things. We might want it to look nice. There are some rather unattractive plants that are really good pollinators.”
Soil stability and wildlife issues may also affect which plants should be used in a mix.
Plants that can compete with weeds will be more successful, but growers also don’t want plants that are too aggressive and will take over.
“Sometimes farmers and ranchers want pollinator habitat that will make some money, too. They can look at legumes that flower before harvest or can be used as a feed source. People have different goals,” he says.
Considerations for a good design also incorporate three classes of variables, including those related to the plants themselves, those related to the site and those related to management practices.
“How compatible is a plant with its neighbor?” he asks. “The season of the bloom is also really important. We want early, mid- and late blooming if we want to really enhance a pollinator habitat.”
Site-related factors include soil types, rain amounts, precipitation timing and seasonal temperatures.
“We want to be well versed in our soils and climatic issues,” Scianna suggests.
Management practices such as irrigation, fertilizers and pesticides will also contribute to the ideal mix for a specific grower’s goals.
Creating a blueprint for the mix itself is also important and involves considering which seeds will be included, as well as how many seeds should be incorporated into the mix.
“We don’t necessarily want to have equal amounts. This is an important consideration, and we’re probably going to need some help with this. It’s all based on seed size, the number of seeds per pound and some kind of fudge factor for how aggressive they are,” he explains.
Being aware of the differences between pure live seed (PLC) and pound-based mixes is another factor to consider when looking at seeds, and how they are planted will also impact the number of seeds needed.
“If we use a drill, we have a standard rate, and we can look on a chart. NRCS has great information. If we broadcast it, it is recommended to double the seeding rate, because we’re going to get about half the survival rate,” he comments.
Different species should also be planted at different times in the season, and their dormancy mechanisms may affect when they germinate and grow.
“Mother Nature often puts a dormancy mechanism in the seed, so it doesn’t grow until the following spring,” mentions Scianna.
Site preparation is another important factor in creating pollinator-friendly plantings, and Scianna recommends thinking about a site a year or two in advance to be sure that unwanted plants have been removed and the area is ready for the desired species.
“We’re going to be doing frequent weed control, especially the first year or two after we plant,” he adds.
Scianna encourages growers to talk to local NRCS office staff or get in touch with the Plant Materials Center to learn more about which plants are best for their particular goals.
“There are some nice opportunities to try something new and be successful,” he says.
Joe Scianna spoke at WESTI Ag Days in Worland on Feb. 20.