When Ken Miller graduated from the University of Missouri with a bachelor of science in horticulture in 1982, he launched his career by becoming a consultant. He was one of a handful in the St. Louis area. Within a few years, he had attracted such clients as Ralston Purina, Pantheon and the Parkway School District. Much to his dismay, Miller, who is 50, also discovered early on that his Mizzou degree left him lacking in basic knowledge of plants — yet he was tops in academics in his fraternity, Alpha Epsilon Pi. He found much better work on horticulture was being done at the University of Illinois.

Over the last two decades, Miller became a highly respected horticulturalist who found himself gravitating toward selling, as he puts it, meat-eating, tiny insects that devour the vegetarian insects that attack the plants his customers wanted to protect. That’s how he got the name — The Bug Store — for his two retail shops, near the Missouri Botanical Garden and in Kirkwood across from the train station.

Miller calls himself a “food Jew” who doesn’t belong to any congregation, though he celebrated his bar mitzvah at the old B’nai Amoona in University City. He is single and lives in the Central West End.

We talked over cups of peach tea in his compact office above his store at 4474 Shaw. As we walked out, he said the building had once been owned by the sister of the comedian Phyllis Diller, who had a pharmacy there.

Why did you start as a consultant? Isn’t that where people sometimes end up later in life?

I was na ïve. For being Jewish, I didn’t have a Jewish cut for business. One of my earliest clients was the condo where my parents lived.

My first year, I had three customers and made $6,000. Condos were popping up everywhere. They wanted someone to care for the grounds, but they didn’t know what they were doing.

Were you busy?

Oh, yeah. There was no one around who knew what I was doing. At our peak, we had a landscape designer, two horticulturalists and a guy who knew agronomy.

Things were never good enough for me. My clients loved me because I killed myself. I even did Sam Fox’s yard. He doesn’t know this, but the contractor brought us in.

What did clients and contractors want?

They wanted local approval on a plant palette, that all these plants are going to live here in this area, through the sudden changes of temperature, and perform together. Few of us in this field know the bloom sequence and esthetic compatibility of plants.

You know, there are those whose texture in our heat look like crap. Our challenge isn’t the extremes in weather, but the changes in extremes. They can happen very quickly. That’s very hard on plants. A plant may look good for a month or two, but then what?

You sound like you enjoyed this period.

I did. I became a designer of plants, but I didn’t have any training. Eventually, I downsized. I was doing landscapes left and right. Mostly they were backyards.

Do you have a nice yard that’s a showcase of your talents, like a display window?

I live in a high rise. My clients’ yards are my front window. Now I have a 50,000-square foot warehouse.

What does that have to do with plant design?

I kept going in any direction that interested me. I have never cared about money. I got fed up with pesticides. My staff sprayed more on themselves than they did on the plants.

The store was true to its name. I tried to make money, but I could not get serious, devoted customers who would stay away from pesticides and just use predacious insects that ate their vegetarian insects.

What are predacious insects?

They are all microscopic. Things like beneficial nematodes and lacewing. We sold them. I would send an order out and maybe it would arrive at the post office, but then the customer had left on vacation. I was throwing 80 percent of my investment away.

You must have a pretty good sense about whether Americans really are changing their habits, whether they are becoming more green in the way they live.

I’ve been through five environmental revolutions. What can I tell you? You can get people to do a thing, like use insects instead of pesticides, for a year. But unless you can hold them, it doesn’t work for someone like me. People are willing to shorten their lives for convenience. They do it all the time.

There are three kinds of customers: People who want to save the planet; people who want to save themselves, and people whose bugs had become a nuisance and they just wanted to get rid of them. I found out that I couldn’t have customer retention, and I couldn’t make money at it.

What happened?

I was approaching 40 and had no retirement. I went to China in 1999 with some other people. I bought eight containers of pottery. Big containers. Forty feet long. The kind you see on trucks. It was the dumbest thing I ever did, but I have customers in every state. I do a lot of trade shows. I have a catalog. People buy things, tsatske, for their gardens and their yards and houses. Most of our business is wholesale now. Our customers are 70 percent lawn and garden retailers. Thirty percent are gift stores.

How has the recession affected you?

We work hard to find new customers.

You started out as an idealist right out of college, and now you have evolved into a businessman, right?

That’s it. I miss the other a lot.