VNS Seed Sources – A Poor Choice

In the commercial seed market, there are many options available for purchase. There are named varieties (i.e. ‘Woodward’ sand bluestem–now an extinct variety), selected native germplasms (i.e. Cottle County Germplasm sand bluestem), and then, from seemingly out of left field, obscure seed products listed as “Native” (native to where?) or “VNS” (Variety Not Stated), or no name listed (i.e. seed for little bluestem sold as “Little Bluestem.” (Seed listed without any commercial or varietal name is considered VNS).

Purchasing unnamed or VNS on the other hand, is a risky gamble, both for your money and for the planting site. VNS seed has no known origin(s), no known traits or performance values in field plantings, and has not been tested in seeding trials. VNS can be from anywhere, is often the result of a “wild harvest,” and is often contaminated with weed seed. (In Arizona, Colorado, Oklahoma, New Mexico, Kansas, and Texas, this weed seed is often old world bluestem or other exotic grass species.) You might think you are saving money in purchasing unnamed or VNS seed sources, but such material often invites expensive control inputs sooner (and later) down the road.

For example, the photo below shows two seed sources of cowpen daisy (Verbesina encelioides) planted side by side in equal amounts of seed (150) in a greenhouse trial. (See Figure 1.) Both trays were planted at the same date and time and given equal amounts of water, air, and light. The visual example of why VNS is a poor choice is striking, and ought to be sufficient proof of concept that the development of native plant materials with known origin(s) and known performance values is a worthwhile and beneficial endeavor to both the commercial seed producer and customer.

Two different sources of Cowpen daisy were seeded (3 seeds per cell) into these 50-cell trays at the same time, same date, and given equal amounts of air, water, light, and temperature regime. Each 50-cell tray occupies about 1.6 square feet of area. Another great indicator here is how well Population A will do within a given square foot of planting space, which is critical to planting success.

Imagine the above scenario in your backyard or rangeland or roadside planting. Which one would you want to see? If your planting site has known invasives or invasive species in adjacent areas, the plants produced from Population A may get a jump on the invasives in establishing a plant community, while the VNS would only invite more trouble.

There isn’t much else that can be said for VNS seed sources. The plants produced from such sources are often found wanting, lacking any great shows of plant performance values (germination rate, overall plant size and vigor relative to a given species, stand density, etc.), and are always the Dollar General of seed quality. Such seed sources should not be recommended to any paying seed customer.

In short, it is best practice to purchase named varieties of seed sources (“Native” is not a named variety). These varieties are of known origin(s), known traits, and known field performance. With named varieties of seed sources, you get what you paid for, and you often see what you paid for in a planting. With unnamed or VSN seed sources, you often see what you did not pay for in a planting.

The NRCS considers a planting to be successful when 20-60 live seeds per square foot are present. This is why it is critically important to purchase seed on a PLS basis and not bulk, and to purchase known and tested varieties and not unnamed or VNS sources.

In the last column of data, imagine a square foot of space within your planting area occupied by annuals, as is often the case in the first few years of grassland plantings due to the nature of succession. In this example, would you want that square foot to be 92% Cowpen daisy–a native annual and a contributor to the emerging plant community–or would you want to take your crapshoot of a chance with VNS, which likely will leave gaps in that one square foot and open the door to any invasives that may be in the soil seed bank or in the adjacent landscapes? You can extrapolate this example into however many acres you might plant and then realize the problem with planting VNS and unnamed seed sources.