Minnesota's Native Orchids

Orchids can be found in every ecosystem type in the state, including native forests, wetlands and prairies, however their biology and ecology are very complex. Species are often only able to reproduce and thrive in the presence of certain pollinators, in specific soil types and with specific soil fungi present. Orchid seeds are among the smallest in the plant kingdom, often about the size of this comma, or this period. At this size there is very little room for error in germination. Due to these numerous constraints, orchids are notoriously hard to transplant or rescue and they are often the first species lost from a disturbed landscape. 

With support from the Stanley Smith Horticultural Trust, we have placed orchid display boxes in the Arboretum’s Wildflower Garden. Temperate terrestrial orchids are difficult to display in a garden setting unless the perfect environmental conditions already exist. Using these boxes we hope to develop techniques and methods to grow terrestrial orchids and share this knowledge with other gardens growing their own native orchids.

A central part of effectively managing and utilizing a long-term conservation seed bank is being able to reconstitute plants and populations from seed. For many plants this is a relatively straightforward process, but not for orchids. Orchid propagation from seed is typically difficult at best because of their unique fungal relationships and habitat requirements.

Orchid seeds are the smallest in the plant world, lacking the food storage (endosperm for some plants or enlarged cotyledons for others) that often makes up the bulk of other seeds. In the wild, they often rely completely on developing a parasitic relationship with soil fungi to germinate and grow. Seeds can be grown asymbiotically, but this is nearly always done in a lab setting. Symbiotic lab germination is a newer technique that is slowly gaining popularity with those doing research on orchids as the ability to extract and propagate fungi gets refined.

We are working with orchid mycorrhizal fungi (OMF) with nearly all of the orchids in the state. We are also maintaining a living library of OMF in our genetic banks to be used for orchid propagation research and conservation.

Seedlings, germinated from wild seed and propagated in our lab, are now being reintroduced to their natural habitats in the Upper Midwest with the help of conservation work in Wisconsin and stakeholders with The Ridges Sanctuary. We continue to propagate native orchids with destinations that include gardens and natural areas around Minnesota as well as areas in Alaska, Illinois, Michigan, Missouri and Wisconsin.

There is not a good understanding of how long orchid seeds will last in storage in a seed bank, even though they are treated as “orthodox” seed. Orthodox seeds are seeds that can be stored successfully by a standard treatment of drying then freezing. Our program is researching how best to store orchid seeds to ensure seed longevity in our seed bank. It seems increasingly likely that orchids are best termed “exceptional species,” meaning that their genetics will not be effectively banked long-term with traditional seedbanking techniques.

The Native Orchid Conservation Program has collaborated with several partners: North American Orchid Conservation Center (NAOCC), Texas Tech, Crown College and the Central Botanic Garden in Belarus. NAOCC, headquartered at the Smithsonian Environmental Research Center (SERC), is a partnership among botanic gardens, universities and nonprofits around the country to preserve North American orchid species. As a core member of the Midwest group of NAOCC, the NOCP's main goal is to create seed banks and the ability to restore populations for all of Minnesota's native orchid species. With researchers at Texas Tech, the Arboretum is working to identify mycorrhizal fungi associates of orchids. Orchid root samples have been collected and sent to Texas Tech to create a catalog of fungi that will be valuable in growing, out-planting and potentially rescuing our native orchid species. Fungal samples have been isolated and sent to Crown College for genetic identification as well. Root samples also have been sent to the SERC for isolation and banking/propagation of mycorrhizal associates, potentially to be used in future restoration work with our native orchids.

The Arboretum’s work with the Central Botanic Garden in Belarus focuses on native and listed species found in both Belarus and Minnesota, as well as an orchid (Epipactis helleborine) which, while invasive in Minnesota, is native in Belarus. The goal of this collaboration is to study orchid ecology and how universal or regional fungal associates might be. The Minnesota Landscape Arboretum is committed to a nationwide effort to preserve and educate about these lovely and important species.