The Many Botanical Journeys of Mary Gibson Henry

1200 miles in 90 days.

On horseback.

Through unmapped territory.

Through blizzards. 

In her fifties. 

Through Canadian wilderness.

In the 1930s.

With 12 carrier pigeons in case of emergency.

To collect rare plants.

This was how Mary Gibson Henry (1884 - 1967) rolled

Henry’s road to becoming one of the great botanical adventurers of her, or any, age, was a long delayed one, but when it came, it came with a vengeance. She was born in Jenkintown, Pennsylvania, in 1884, to a mother whose Quaker roots stretched back to the days of William Penn, and which included George Pepper, one of the early lights of the Pennsylvania Horticulture Society, and a father who was a devoted nature lover. According to her memoirs, she picked up the botany bug while on a family camping trip at the age of seven, when an encounter with a Linnaea borealis, and the woods surrounding and framing it, entranced her. 

Her father passed away a year after that trip, but the family pastime of camping remained. She attended Agnes Irwin School up to the age of eighteen, whereupon her aunt took her on a tour of the American West, touring the Rocky Mountains and Grand Canyon, and drumming into young Mary’s head the dizzying array of natural phenomena available on the North American continent. Her next trip, with her mother and brother, added the natural wonders of Europe to her set of life experiences, including a trek up Mont Blanc.

Though by the early 20th century, college education at multiple institutions was available for women, particularly in the northeast regions of the country, and particularly for women growing up in Quaker communities which valued women’s education, for whatever reason Mary never took this path for herself, and in 1909 she married John Norman Henry, an outdoor enthusiast and physician who would prove to be her greatest support in her later life adventuring and explorations. For the immediate future, however, her responsibilities would tend towards the familial, as she had five children who more than filled her time, though she did manage to steal some moments to grow irises, narcissi, orchids, and lilacs in a backyard greenhouse, even writing an article on orchid growing for Garden Magazine in 1924. 

In 1926 or 1927 the family moved to a ninety-five acre farm in Gladwyne, Pennsylvania, where her love of plants could act on a grander scale, as she raised hundreds of different varieties of trees and shrubs, and carried out extensive projects in hybridization to produce new colors and shape profiles in her favorite plants.  

At the age of forty-four, her husband, seeing her desire to acquire new plants not available through the regular catalogues or shops, told her, “Go to it and go to all the places and do all the things you want to do and I believe are well fitted to do. You have earned it all.” Taking him at his word, she outfitted what is doubtless one of history’s dopest science vehicles, a car made specifically for plant collecting that featured a bookcase, a desk with electric lighting, insulated and ventilated compartments for storing plants, three plant presses, space for tools and notebooks, all kept in running order by a regular driver who would spend the next several decades taking her wherever she wanted to explore. 

Her first explorations occurred in 1929, and over the course of the next forty years she would rack up some two hundred separate specimen finding missions, including several of continent-spanning scale. The first of these mega journeys was set in motion by a tale from a trapper she met while camping in Jasper, British Columbia. He told a story of a “Blind Spot” - an unmapped patch of Canada, notoriously difficult to approach, which boasted waterfalls, hot springs, a “tropical valley”, windswept peaks, and large expanses of boggy marshland. 

The idea was too enticing to resist - a tropical zone set in the midst of the frigid Canadian wilderness? What rare varieties of plant life might such a place hold? John and Mary took nine months in planning the trip out, poring over reports of past failed expeditions to the region, organizing a nine man, 58 horse party along with all of the resources needed to support them, and arranging with the topographer K.F. McCusker to join them to produce maps of the region as they went. They left home on June 25, 1930, arriving at Fort St. John, where they met their expedition team, mounted up, and headed out west. 

The party made on average seventeen miles a day, with Mary frequently dismounting to collect new plants that caught her fancy and place them in the empty cans she had placed in her saddlebags that morning. Of course, these were not ideal conditions for the long term preservation of specimens, and a solid two thirds of the plants collected did not survive the transit, but those that made it proved an invaluable source for researchers the world over. The team followed paths made by local tribes, and when those were lacking, followed those made by bears, wolves, and elk, as they wended their way up past the treeline. On August 5 they came across a 9000 foot peak that McCusker dubbed Mount Mary Henry, a name subsequently approved by the Canadian government, and by which it is still known today.

Soon thereafter, the team arrived at a Sikanni camp, where the chief’s son agreed to take them to the fabled tropical valley which their trapper contact had told them of a year before. Find the valley they did, though the impact of it was blunted somewhat by a recent fire that had swept through the region. Mission accomplished, and samples taken, they turned back towards home, arriving at their start point after eighty days and a thousand miles of travel through uncharted, blizzard-prone wilderness. Mary had netted fifty cans of new plants, and seventy-six packages of seeds, and was soon at work creating herbarium sheets for collections in Scotland and Philadelphia. 

Though the culminating moment proved something of a let down, on the whole Mary found the trip exhilarating, and would make a regular habit of these excursions over the decades to come, including the epic 1200 mile trek through the Northland mentioned above, terminating at Wrangell, Alaska, on October 2, 1935. Future collecting trips included expeditions to Bolivia, Honduras, New Mexico, Oklahoma, Texas, Mississippi, Arkansas, Louisiana, and her favorite azalea hunting grounds, the swamps of Georgia.

She wrote popular accounts of her excursions for National Horticulture Magazine, as well as more technical articles about the soil mixtures and greenhouse methods best adapted for raising more tropical type plants in the harsher climate of Pennsylvania. Over her career, she discovered some fifty new species, and created a rare plant garden that served as a feeder farm for some of the region’s botanical catalogues and nurseries, as well as providing individual specimens for collectors the world over who had heard of Mrs. Henry’s miraculous expeditions and the rare plants she had hauled from deep wilderness. She remained collecting into her eighties, logging 42 field days and 75 plants in her eighty-first year. 

Mary Gibson Henry passed away at the age of 82 while on a collecting expedition in North Carolina, which is likely exactly how she would have wished to go. We continue to remember her today less for the hundred articles she wrote, though those are a priceless capsule of early 20th century botanical knowledge, or the hundreds of specimens she sent to botanists and horticultural societies the world over, though those proved especially valuable records in the light of the increasing habitat destruction in North America that stalked the Twentieth Century, but rather for her example of absolute love of her craft and devotion to nature which radiates from her memoirs and life. This was a person who saw a miracle in each flower she met, and in communicating that sense of the miraculous to the world, she brought more people into the mid-century wilderness conservation movement, allowing us to hold on to those few protected spaces we still had, where we can walk, and wander, and experience a small bit of the wonder that Mary Gibson felt as a seven year old beholding Linnaea borealis and feeling, somewhere deep within her, that these small creatures were to be the work of her life.

FURTHER READING:

I first came across Henry’s story in Penny Colman’s Adventurous Women (2006), which is a fun little volume that includes a couple of figures we’ve talked about before, including Louise Boyd and Alice Hamilton, and then again in Stefan White’s gorgeous Heroines of Horticulture (2024). Both of them have a handful of pages devoted to her, but luckily their focuses are slightly different so between them you get a nice interleafing picture of her life and work.