||A study funded by the Montana Board of Research and Commercialization Technology was initiated in 2010 to evaluate the impact of thirteen morphological and physiological characteristics on the harvest efficiency of native wildflowers in the US and Canada. The cumulative total of the positive and negative influence of these characteristics on seed harvest resulted in a Harvestability Index (standard combine harvest) for each of 388 commonly traded native wildflower species. A second Harvestability Index was developed for the Arbuckle Native Seedster™, a front-end loader mounted seed stripper/plucker that utilizes a counter-rotating brush and combing drum to dislodge and capture seed in a seed hopper. The plant characteristics that were documented included plant growth form, plant height, foliage density, inflorescence position in relation to foliage, type of inflorescence, flowering and ripening uniformity, tendency to shatter, seed container type, container integrity, seed type, seed size, seed and container appendages, and seed surface. The characteristics determined to have the greatest impact on harvestability were plant height, flowering and ripening uniformity, tendency to shatter, seed and container appendages, and container integrity, respectively. The harvest efficiency of species that ripen over an extended period of time is relatively poor when harvested with the direct combine or swath and combine method, but is considerably improved by using multiple harvests with a Seedster as the seed progressively matures. Seed appendages make it difficult to glean through the sieves of a combine, but rather than hinder the harvest efficiency of the Native Seedster, these appendages contribute to harvest effectiveness. Seed containers that are rigid or seed that is recessed into the receptacle require the extra threshing action of the cylinder/concaves of a combine to dislodge and capture the seed.