An Interview With Botanist Walter Kittredge

This blog is going to be a departure from the many entries I have made in the past. I am taking a page from Margaret Roache’s A Way To Garden blog where she provides a transcript of conversations she has with experts in the field of horticulture. My first venture into this style of blog begins with someone who I know very well for the simple reason that he is my younger brother Walter. This is not a case of nepotism however, as he has had an interesting life (so far) in the field of botany.

Walter is a 1975 graduate from the University of Maine with a B.S. degree in botany. He has spent his career as a taxonomist working at the world renowned Gray Herbarium at Harvard University. He has just recently retired from his work at Harvard to begin a new venture, creating a native plant nursery called Oakhaven Sanctuary. But enough of the introduction. Here is the transcript of our conversation about his life’s work.

(John Kittredge) So Walter, you started out as a Botany student at the University of Maine. Didn’t you win some kind of award there? Best botany student or something like that?

(Walter Kittredge) I think I did but I don’t remember now. You have a great memory, but I don’t remember what the award was.

(John) Didn’t you reorganize the University of Maine Herbarium while you were there?

(Walter) When I was a senior I was in charge of seven undergraduates in reorganizing the herbarium. Because I had worked at the Harvard herbarium the summer before and had worked at the New England Club Herbarium, I thought the UMO herbarium should follow the same pattern. So we began to reorganize it.

(John) How did you come to work at the Harvard herbarium when you were undergraduate at UMO?

(Walter) The previous summer I had worked for a researcher at UMO conducting a research experiment growing potatoes in buckets. Potatoes are big in Maine of course.

(John) That was in the 1970s! And now growing potatoes in grow bags is the latest thing to do.

(Walter) Well, the experiment had to do with plant physiology. I got to go up to Aroostook County to view the potato farms. That was quite an experience.

(John) I bet! Well, Dr. Richards was one of my favorite botany professors at Maine, and yours as well.

(Walter) Dr. Richards was my major professor and a mentor early on as well as Dr. Homola who taught a class on fungi. Unfortunately they didn’t offer a course on lichens but I did take every botany course they offered. Dr. Homaloff also taught a course on mosses. That was the only class I got a B in. (Laughter) I have continued to study them since and I have become very good at identifying them because somebody published the Mosses of Maine. It is a wonderful guide. That’s how I learned the mosses.

• 

• 

• 

Dr. Richards on the left and Dr. Homola on the right. Both Professor Emeritus at the University of Maine

(John) How did you come to get your job at the Gray Herbarium at Harvard University?

(Walter) I believe Dr.Richards informed me of the opportunity. I walked in and asked them and they said sure. They were always taking in summer students. Once I got my feet in the door for the summer, and they learned of my work ethic, they were very eager to have me come back after I graduated.

(John) How long did you work there?

(Walter) Forty-five years. I started in 1975 and retired in 2021.

(John) Were there some highlights during those years that you worked there?

(Walter) I think the highlight for me was that I was instrumental in changing many ways in which the herbarium was run and organized. I did work with a world famous orchidologist for a couple of years and we published a few research papers. I really enjoyed that.

(John) An orchidologist. Would that be someone who studies orchids?

(Walter) Yes. Orchids.

(John) How many different orchids are there in the orchid?

(Walter) I have no idea. I think there might be over 28,000 species.

(John) OMG!

(Walter) It’s one of the largest plant groups, mostly in the tropics.

(John) You also worked on Henry David Thoreau’s collection, didn’t you?

(Walter) Yes I did. With the bicentennial of Thoreau’s birth coming up, Harvard realized they should make his collection available to the public. So they photographed all of his specimens. His specimens are kept in the Gray Herbarium Library archives. Part of the reason is that they are on oversized sheets, rather than the standard 12X15 sheets. His were on sheets that were probably twice that size.

(John) Would he have known what the standard size was?

(Walter) There was no standard size in Thoreau’s time. So people had their own herbariums. The most common way of keeping them was in a bound book of plant specimens.

(John) Why would Thoreau have even done this?

(Walter) He was in communication with the Harvard zoology professor Louis Agassiz. Thoreau was collecting specimens for Agassiz. He collected turtles, fish and frogs among others.

• 

• 

• 

Left to right: Dr. Louis Agassiz; Dr. Edward Hoar; and Henry David Thoreau. (Note) Dr. Agassiz was a contemporary of Asa Gray and Henry Wadsworth Longfellow. Dr. Agassiz stood in opposition to Charles Darwin’s theory of evolution. Dr. Agassiz was the first to hypothesize that the earth was once subject to an ice age with much of North America covered in ice miles thick. Dr. Hoar was a life long friend of Thoreau.

(Walter) In 1850 or so, Thoreau decided that he didn’t like killing animals. So he decided that he would collect plants and study plants instead. Part of the reason that he did that was that he had a very close friend Edward Hoar. Hoar had his own personal herbarium and was a very good botanist.

(John) Was Hoar also from Concord?

(Walter) Yes, he was from Concord. What Thoreau was doing was to go out daily to try to find out what the first date for flowering was for every plant in Concord. He had to go every year, and every day to try to assess when a plant was about to flower. So, often in his journal he wrote about such and such a plant, three days. That meant that he thought the plant had been in flower for three days.

(John) So you were reading Thoreau’s actual handwriting to see the notes? How was it to read his handwriting?

(Walter) His handwriting was atrocious! He wrote on scraps of old newspaper and of course the script from that time was different than ours. So I had help reading them from Ray Angello, who is a Thoreau scholar, particularly in the botanical realm. What Thoreau was doing was trying to assess the phenology of flowering plants because he thought this would show the hand of God in nature. Because of course, Thoreau was a Transcendentalist. Phenology is the timing of things. In this case, the timing of flowering.

(John) Botanical phenology is still being done today.

(Walter) Very much. A professor at Boston University looked at Thoreau’s journals and the timings of plant flowering. He also looked at the flower timings of plants collected by the staff at the Arnold Arboretum in Jamaica Plain, Boston. He was able to show that flowering times now are advanced a week or two weeks ahead of Thoreau’s time.

https://www.theguardian.com/books/2012/mar/14/henry-david-thoreau-climate-change

(John) So does that support the theory of climate change?

(Walter) Yes, exactly.

(John) So your work with Thoreau’s herbarium was important work.

(Walter) Yes. Very important.

(John) You have come to the end of your forty five years at the Gray Herbarium and you retired. But you are not ready to kick back.

(Walter) During the pandemic year, while I was at home working on-line, I had extra time, not having to commute to work. I used that time to pot up a lot of the perennial plants that grow on our property and the surrounding area. In doing so I built up an inventory of over a thousand plants which I intended to use to start up a nursery.

(John) Tell me about how you came to think of starting a nursery.

(Walter) It started with the Native Plants of New England Facebook page where people would write that they wanted to grow a particular plant but they couldn’t find it in an nursery. So I thought I could be that person who provides native plants for people to grow. Also, as a field botanist, I know where there are populations that I could draw from. I did a lot of plant rescues from road and building construction.

(John) Many people would say that you have a passion for native plants.

Oakhaven Sanctuary Native Plant Nursery in North Reading, Mass.

(Walter) It has been a developing passion. I trained as a standard horticulturist in college and have gardened in the standard fashion all of my life with the standard offerings available in nurseries. But as an ecologist I have become aware of climate change and its effect on the environment. I have done research about that. We conducted research at the Middlesex Fells Reservation. https://www.mass.gov/locations/middlesex-fells-reservation It’s flora was documented when it was first set aside for conservation in 1894. Recently we were able to collect the plant specimens again to compare the changes over time. One of our observations was an increase in non-native plants. On top of that is the news of the decline of native insect populations. So all of this converged into my growing realization that we need to do more to bring native plants back into our landscapes.

(John) Back into our landscapes?

(Walter) When people started to do landscaping, such as Warren Manning, who was a protege of Frederick Law Olmsted, they did a lot with native plants. Manning was a botanist and a very good one. It was common back then for them to do natural landscaping. They tried to make the landscape look as natural as you might see anywhere in the wild. But of course it was entirely artificial. the Arnold Arboretum is designed very much along these lines. They tried to make it look as natural as possible while planting the entire world’s temperate flora.

(John) Which is anything but natural.

• 

• 

• 

Frederick Law Olmsted on the left. Warren Henry Manning on the right. A wild garden design in the center picture. Warren Henry Manning was an American landscape designer and promoter of the informal and naturalistic “wild garden” approach to garden design. In his designs, Manning emphasized pre-existing flora through a process of selective pruning to create a “spatial structure and character.

(Walter) Yes. At some point in time the nursery trade dropped native plants in favor of non-native plants. The reasons are probably very simple. One is that they are generally very tough, yet easy to grow in many situations. Also they don’t have many disease or insect problems because they are from other parts of the world and they left those problems behind. The problem is that since no native insects feed on them, then they don’t provide food for other wildlife.

(John) So by going to native plant you are helping the native insect population.

(Walter) The idea is to work towards an ecological balance. This is a broader concept of trying to pull the native plants back into our consciences as something that is part of our lives. In doing so we can enrich all of nature. Then we will have a more healthy environment to live in. Hopefully we can begin to reverse the declines in native plants we have seen.

(John) So your big effort now is that you have opened up your native plant nursery called Oakhaven Sanctuary in North Reading, Mass. How many plants do you have potted up?

(Walter) I have three to four thousand native plants potted. This includes herbaceous perennials, ferns, shrubs and trees. This year I have started growing natives from seed. This requires winter stratification where the seed is sown in the fall and left outside for the freezing and thawing cycles. They then germinate in the spring. I am growing plants in plug trays for volume. There are others who are doing this too so we can get together and trade excess seedlings to collaborate on having different kinds of plants.

(John) In the American model it is all competition but what you are doing is collaborating with your competitors, right?

(Walter) Well, one difference is that the people I am collaborating with are also doing consulting for ecological restorations.This is different from garden nurseries. Restorations require large number of plants. The stormwater restoration that was done at the Alewife Brook Reservation in Cambridge required one hundred thousand plants. These are sold as plugs which comes at a lower price so you can do a large volume and a large landscape as opposed to somebody’s yard.

(John) Are regular plant nurseries becoming interested in this market?

(Walter) Yes. This year the Mass. Department of Conservation and Recreation has started a new program for pollinator gardens. They oversee over a hundred state parks in Mass. So nurseries are going to provide pollinator starter kits. I don’t know what will be in them but often plants that are native to the midwest or from down south and are not native to New England are sold as natives. On top of that some are selling nativars. That is a native plant that has been cultivated for a special attribute such as color or size. There has been research showing that cultivars may not be as effective for our native pollinators. The idea in horticulture is to produce something new and improved so you can sell more at a higher price. The economics is moving the cultivars while the native plant movement is focused on the ecology.

Mt. Cuba Center (a horticultural research station) puts nativars to the test. https://www.indefenseofplants.com/blog/2018/2/6/mt-cuba-center-puts-nativars-to-the-test

(John) Well, this has been a very interesting and educational conversation. I think I would like to continue this conversation at another time but I understand that you have to run off to sell some native plants at Oakhaven Sanctuary.

(Walter) That’s right. I have customers.

(John) Thank you so much for doing this interview. I will be posting this in my blog for others to read. I hope people will will respond to what you have said.

(Walter) It was my pleasure. I hope your readers enjoy it.