Research on Native Plants for Provision of Summer Nectar and Pollen

Spotted knapweed blooms over an extended period in mid to late summer, providing pollen and nectar to a variety of insects. In areas where knapweed is managed, it may be desirable to establish plants that bloom during the same period to maintain these resources in the landscape. MSU researchers are investigating the potential of native plants to provide summer pollen and nectar resources to a variety of insects. The aim of this research is to investigate the establishment and effectiveness of seed mixes that could provide a diversity of flowering species and are appropriate for a wide variety of sites in Michigan.

Currently, spotted knapweed is commonly found growing on dry to dry-mesic soils of relatively low fertility. Such sites would have historically supported oak barrens, pine barrens, dry sand, and dry-mesic prairies containing a wide variety of mid to late summer blooming plant species. Using description of these habitats from the Michigan Natural Features Inventory, the researchers selected a subset of species that historically grew these habitats and which met the following criteria:

  • Plants native throughout Michigan (both Upper and Lower Peninsulas)
  • Available as seed from Michigan native plant producers

From these species they created two mixes for further testing. Mix #1 is a relatively low diversity mix comprised of 3 grasses and 8 forbs. Mix #2 is a moderate diversity mix containing the same 3 grasses species and a total of 16 forbs. In each case, the total seed weight of grasses and forbs was maintained the same in both treatments. Grasses are included as they are historically part of these habitats and many facilitate future management through prescribed fire. This research is in its initial phases but will be updated as results become available. In the meantime, land managers may use the following information as a starting point for conducting their own trials.

Mixture #1

Plant typeCommon nameScientific nameoz/A
Forbs Candle anemone Anemone cylindrica 2
Forbs Common milkweed Asclepias syriaca 14
Forbs Lanceleaf tickseed Coreopsis lanceolata 6
Forbs Flowering spurge Euphorbia corollata 6
Forbs Tall blazing star Liatris aspera 8
Forbs Wild bergamot Monarda fistulosa 2
Forbs Blackeyed Susan Rudbeckia hirta 2
Forbs Gray goldenrod Solidago nemoralis 0.5
Grasses Big bluestem Andropogon gerardii 12
Grasses Prairie Junegrass Koeleria macrantha 4
Grasses  Little bluestem Schizachyrium scoparium 16
Total 72.5

Mixture #2

Plant typeCommon nameScientific nameoz/A
Forbs Candle anemone Anemone cylindrica 1
Forbs Common milkweed Asclepias syriaca 7
Forbs Smooth blue aster Symphyotrichum laeve 2
Forbs Lanceleaf tickseed Coreopsis lanceolata 3
Forbs Showy ticktrefoil Desmodium canadense 8
Forbs Flowering spurge Euphorbia corollata 3
Forbs Rabbit-tobacco Pseudognaphalium obtusifolium 0.1
Forbs Woodland sunflower Helianthus divaricatus 5
Forbs Tall blazing star Liatris aspera 4
Forbs Wild bergamot Monarda fistulosa 1
Forbs Spotted beebalm Monarda punctata 2
Forbs Foxglove beardtongue Penstemon digitalis 2
Forbs Blackeyed Susan Rudbeckia hirta 1
Forbs Early goldenrod Solidago juncea 0.25
Forbs Gray goldenrod Solidago nemoralis 0.25
Forbs Showy goldenrod Solidago speciosa 1
Grasses Big bluestem Andropogon gerardii 12
Grasses Prairie Junegrass Koeleria macrantha 4
Grasses  Little bluestem Schizachyrium scoparium 16
Total 72.6
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