33 'Bonanza' Secrets The Production Crew Hid For Years

Lorne Green: Then

For 14 years and 431 episodes, “Bonanza” was a fixture of American life. The show chronicled the life and adventures of the Cartwright family, led by their patriarch, Ben Cartwright.

In this post, we’ll look at some little known facts about the show and see what happened to the stars of the show after it ended in 1973.

Born in 1915, Canadian Lorne Greene played the patriarch of the Cartwright clan, Ben Cartwright. Before working on Bonanza, Greene was best known as a reporter and the main radio announcer for the Canadian Broadcasting Company during World War II.

Lorne Green: Later

The gloomy news that he announced during WWII along with Greene’s deep, booming voice earned him the nickname “The Voice of Doom.”

After his many years starring as the head of the Cartwright family on “Bonanza,” Green continued to work in television. Some of the shows he starred in included “Battlestar Galactica” and “Code Red.” He was also a sponsor for a number of commercials for Alpo dog food.

Not Another Idiot Father

Television’s much beloved “Pa” passed away in 1987 at the age of 72.

In 1959, when “Bonanza” originally premiered, the television landscape was filled with shows that featured fathers who were depicted as idiots managed by their wives.

So THAT'S Why They Never Changed Clothes

David Dortort, the producer of the show, wanted to depict Ben Cartwright as a father figure worthy of respect, which caused him to insist that the show be an hour long instead of only 30 minutes so that there was time to properly portray this character.

Viewers who were paying attention may have noticed that the outfits worn by the show’s main characters were the same for most episodes. The reason?

Michael Landon: Then

So that it was easier to work in stock footage when necessary. Although you’d think this would lower the production costs for the show, at $100,000-$150,000 per episode, it was still one of the most expensive shows of its time.

Michael Landon starred as Little Joe Cartwright, the youngest member of the Cartwright clan and perhaps the most beloved by the shows fans.

Michael Landon: Later

Before his 14 year career on “Bonanza” as the heart and soul of the show, Landon had a number of small roles in a number of movies and TV shows, including the low-budget horror film entitled “I Was a Teenage Werewolf.”

After “Bonanza,” Michael landed another big role as Charles Ingalls on “Little House on the Prairie.” This series was an instant hit with audiences and Landon got the chance to play a new role as a responsible, hard-working husband and father. After “Little House” came another hit, “Highway to Heaven,” which Landon directed, wrote, and acted in.

Landon's Real Name

Landon died in 1991 after battling pancreatic and liver cancer.

“Michael Landon” – it just sounds like the name of someone who was born to be an actor. However, this was not actually Landon’s birth name. In fact, Michael Landon was born Eugene Maurice Orowitz.

The Cast's Other Talent

He chose his new stage name from a phone book. Initially, he chose the name Michael Lane, but there was already an actor enrolled by this name in the Screen Actor’s Guild. So, another look through the phone book led the actor to stumble across the name Alf Landon, and so Michael Landon was born.

We all know they can act, but did you know that most of the show’s main actors can also sing?

Pernell Roberts: Then

In fact, most of the actors created their own albums at one time or another, and all four of the Cartwrights sang in a 1964 Christmas-themed album titled “Christmas at the Ponderosa.” Lorne Greene even had a single, “Ringo,” that was a huge hit in the US and Canada.

Pernell Roberts played the oldest Cartwright son, Adam Cartwright. After only working on the series for 6 years, Roberts decided to leave the show.

Pernell Roberts: Also Then

He didn’t leave the show on the best of terms and was ultimately fired by NBC. However, this wasn’t the end of his career, as we’ll soon see….

In the immediate aftermath of leaving “Bonanza” and being fired by NBC, Roberts went on to do some stage work, starring as King Arthur in “Camelot” and appearing in several prestigious theaters alongside the likes of talents such as Ingrid Bergman.

This Actor Despised the Show

Roberts also starred in many television shows after “Bonanza,” notably appearing as the title character on “Trapper John: M.D.” He retired in the 1990s and died in 2010 at the age of 81 following a battle with cancer.

We already know that Pernell Roberts left “Bonanza” after six years on the show, but you may not have known that his hatred of the show started right out of the gate. In fact, it was only after six years of constant pressure that NBC finally gave in and let him go.

The TV Show That Inspired a Restaurant Chain

Roberts’ politics and lack of regard for the intelligence of the script were some of the main reasons for his intense dislike of the show.

If the names of the restaurant didn’t immediately give it away, we’ll confirm it: the Ponderosa/Bonanza Steakhouses were, indeed, inspired by the TV show. Dan Blocker founded the first American Bonanza Steakhouse in Kokomo, Indiana in 1965.

Dan Blocker: Then

The chain had expanded to Canada in 1971. The restaurantsare owned by the Metromedia Restaurant Group.

Dan Blocker was the middle son of the Cartwright family, Eric “Hoss” Cartwright. His character was gullible, sweet, and a little dimwitted, which was quite the opposite of Dan Blocker in real life.

Dan Blocker: Later

Before getting involved in acting, Blocker received a Master’s degree and worked as a teacher. Leading up to his role in “Bonanza,” Blocker also worked in a number of Westerns.

Sadly, “Bonanza” was the last show that Blocker ever worked on. In 1972, at the age of 43, he died suddenly from a lung clot.

The Largest Baby Ever Born in a Town in Texas

His death occurred just 19 days before production on the show’s 1972-73 season was scheduled to start. The show apparently couldn’t survive without Blocker, as its first season without the actor also proved to be its last.

This fact is definitely one that only the most diehard fans of the show will likely know. Weighing in at 14 pounds at birth, Dan Blocker was, at the time, the largest baby ever born in Bowie County, Texas.

From Barely Surviving to Thriving

By the time he reached the first grade, Blocker already weighed a whopping 105 pounds.

If not for the fact that “Bonanza” was one of the first TV shows ever to be filmed and broadcast in color, the show may never have survived its first season on air. Initially, the show aired on Saturday evenings, where its ratings were dismal.

David Canary: Then

However, because NBC was intent on keeping the show running due to its color production, they moved it to Sunday evenings, where its ratings soared. “Bonanza” eventually reached number one in 1964.

David Canary was brought onto “Bonanza” and cast as “Candy” Cannaday to help fill the gap that was left when Pernell Roberts left the show. Canary’s character was the honorary foreman of the Ponderosa ranch, and he ended up being involved in many of the family’s adventures.

David Canary: Later

Before his time on the ranch, Canary worked on several other TV shows and off-Broadway plays.

Canary’s history with “Bonanza” was checkered, as he left the show in 1970 due to salary disputes but ended up returning in 1972 (with a new contract for a higher salary) at the request of Michael Landon. After “Bonanza,” Canary went on to star as Adam Chandler in “All My Children” between 1983 and 2010, when he announced his retirement.

The Ponderosa Ranch--From Disappointment to Delight

David died of natural causes in November 2015.

Because of the success of the show, many fans made the trip to Incline Village, Nevada, the location of the fictional Ponderosa, only to be disappointed when they arrived to see nothing there. Sensing opportunity, land developers Bill and Joyce Anderson partnered with the producers of the show to develop a large theme park in Incline Village, which included a complete recreation of the ranch house.

Hop Sing--He Didn't Just Play a Chef on TV

Portions of the show were even filmed at the park, and it continued to attract fans until it closed in 2004.

In a case of art imitating life, Victor Sen Yung, the actor who played the Cartwright family’s chef Hop Sing, was actually an accomplished chef in real life.

A Western Retelling of King Arthur

After the show ended, Yung supported himself by appearing on cooking shows and authoring The Great Wok Cookbook in 1974.

When Dortort started to think about the show and how it would be put together, he pictured it as an Old West presentation of the legend of King Arthur. In his vision for the show, Ben Cartwright was King Arthur and his sons were his knights.

This Stock Footage Trick Saved a Ton of Money

In many ways that premise came true as Ben led and guided his children through life.

Have you ever noticed that the characters outfits were the same almost every episode? The show’s producers realized that they could easily insert stock footage if the same clothes were used.

Still One Of the Most Expensive Shows on TV

It was a simple but very effective trick that cut out plenty of big shoots that would have inflated the show’s budget.

Even with the same clothing being worn every single episode, the show was still not cheap. The network was spending between $100,000 and $150,000 per episode.

Zorro Could Have Played Adam Cartwright

That made Bonanza one of the most expensive scripted shows to produce on a weekly basis. It was also one of the best performing TV shows which helped justify the large amount of money spent on each episode.

Guy Williams, the actor who played John Robinson on Lost in Space, was offered the chance to play Adam Cartwright. Williams decided instead to play the role of Zorro.

Hoss Had a Real First Name

While he never took on a main role, he did appear on five episodes of the show as cousin Will Cartwright. His character was created as a replacement for Pernell Roberts in case he ever walked off the show.

Did you know that Hoss Cartwright was actually named Eric Haas Cartwright. His family and other characters on the show always used the nickname “Hoss” which was a play on his middle name.

Fans Started Joking About the "Cartwright Curse"

If you weren’t a die-hard fan of the show you might have missed that little recognized fact.

Every woman that Cartwright fell in love with either ended up dead or left town.

That's a Lot of Fake Hair

It became a joke among the shows actors and fans and there was obviously a “Cartwright Curse.” We would have settled for just one marriage that lasted but this dad was obviously cursed to raise his kids as a strong father figure with no mom in sight.

It’s really amazing how many guys on the show wore a toupee. Among that impressive club were Blocker, Roberts, and Green.

Equal Screen Time Was Very Important

Michael Landon managed to appear on the show with his own full head of hair. If you watch closely you’ll realize that the hair on the show was just as real as the show itself.

The four men of the Bonanza household shared screen time. It was really important for the show’s producers that none of the stars overshadowed the other three.

The Cartwright Curse May Have Extended To His Sons

Every script was closely scrutinized to make sure there were four stars during every episode. It paid off and led to a very well-balanced show that offered the chance for many stars to shine.

It wasn’t just the family’s patriarch who had trouble keeping his wives in town or alive. Whenever his boys would fall in love the women they liked would either fall ill, die, or leave town with another man.

The Show's Title Is Slang

The Cartwright Curse was apparently a family problem that just wouldn’t go away.

Here is a fun language fact from the show. Bonanza was a slang term used by miners to describe a large mineral deposit or ore.

The Other Reason For the Same Clothing

It’s also a term that is synonymous with “jackpot.” A real life bonanza was discovered right by the Cartwright’s ranch in the famous Comstock Lode.

Yes, wearing the same clothing made it easy to insert stock footage, but it came down to more than that. When editing footage from the show, reshoots were easier to match up with great continuity because the clothing on the actors and actresses were always the same.

The Show Stayed on TV To Sell Color TV's

Apparently an encapsulated wardrobe has a ton of positive returns for TV producers.

Bonanza was one of the earliest TV shows to be filmed in color. It was partially kept on the air as it struggled to gain an audience because NBC’s parent company RCA, wanted to sell more color TVs.

Michael Landon Was Obsessed With the Show

As the TV show increased in popularity it didn’t have to rely any longer on its ability to sell color TVs.

Michael Landon didn’t just have a role on the TV show, he was also highly devoted to every filmed frame. Landon appeared in all but 14 of the shows 416 episodes.

Landon Was Also Incredibly Hard to Work With

It was also the show where Landon started his writing and directing career. You might not be aware that Landon actually wrote and directed some of the series’ most beloved episodes.

As the show started to lose its luster and entered into its final five seasons, Landon became incredibly hard to work with on a daily basis. It was rumored that Landon made sure that no new major characters were introduced to the show.

Dan Blocker Was Turned Down For a Role in Nash

He also regularly delayed production shoots as he attempted to create his own vision for the series.

Dan Blocker was considered one of Robert Altman’s top choices for a lead role in the movie MASH. Altman fought for his part in the film but the movie’s producers refused Altman’s request to cast Blocker.

It Was The First Time a Show Acknowledged a Character's Death

The movie was still a huge success but it would have been interested to see which role would have been written for one of TV’s favorite actors.

After Blocker’s unexpected death, it was announced that Hoss would be killed in an accident in an episode of the show. It was the very first time in television history that a show had dealt with, or even mentioned, the death of one of its characters.

Guest Stars Were Paid More Than The Show's Stars in the First Season

“Just as we personally suffered a loss,” explained Bonanza producer Richard Collins, “so the audience suffered one, too.”

For the first season of the show it wasn’t a certainty that viewers would tune in to watch a bunch of unknown actors. In response, many famous guest stars were brought in for guest appearances.

Johnny Cash and the Bonanza Theme Song

The show’s producers paid those actors more than the show’s actual stars. By the second season the show’s ratings were increasing and the show’s actors has become bonafide stars.

We know the instrumental side of the Bonanza theme song but it also had lyrics.
The song was created by Jay Livingston and Ray Evans and there is footage of the lead actors singing those lyrics. Lorne Greene, Dan Blocker and Michael Landon sang a lyric version for the pilot, but it never aired.

The First Western TV Series Filmed 100% In Color

Famed singer Johnny Cash recorded his own version of the theme Bonanza theme song.

Bonanza wasn’t just filmed in color, it was the very first US Western TV show to be 100% produced in color. That decision was partially why it was so expensive to film the popular TV series.

It Was the Second Longest Running TV Western of All Time

If it wasn’t for that decision the show would have been canceled before it had the chance to become one of the most popular TV shows of all-time.

The only Western TV series to run longer than Bonanza was Gunsmoke. Bonanza ran for 14 seasons and Gunsmoke ran for 15.

There Was a Very Good Reason The Cartwright's Were Not Hostile To Visitors

Syndication for both shows continues in various parts of the world up until this very day. If you love westerns and you have not watched Bonanza we highly recommend hunting down the series and watching it while you still can.

During the first few shows the Cartwright’s were hostile to visitors who came onto their land. However, Lorne Green soon realized that the family ran an important business for the community.

The Chevrolet Connection

That meant many people would visit their homestead to conduct business. The show’s characters were soon altered to make them more approachable for their fellow neighbors.

A large portion of the TV show’s budget was earned by a long-standing partnership with Chevrolet. The car company sponsored almost all of the TV show’s 430-episodes which helped keep the series in production.

The Show Has A Deep Connection To The Original Star Trek

The stars appeared in numerous Chevrolet commercials as part of the sponsorship deal which showed them endorsing various vehicles.

Almost every major actor from the 1966 TV series Star Trek appeared at some point during Bonanza’s run.

Landon’s Repeated Attempts To Write Scripts For The Show Originally Failed

If you are a fan of the show you can catch the following guest stars in various roles: William Shatner, James Doohan, Leonard Nimoy, DeForest Kelley, Nichelle Nichols, George Takei, Grace Lee Whitney, Majel Barrett, and Walter Koenig.

Show producer David Dortort wouldn’t allow Michael Landon to write scripts for the show. While his first attempts failed, Landon eventually submitted a script that Dortort thought was good enough to produce.

It Was The First Issue Oriented Western TV Show

Not only would he become a regular writer and occasional producer on the show, he eventually wrote many scripts for Little House on the Prairie.

Bonanza was the first “dramatic” TV Western that didn’t focus on hunting down and killing bad guys. Instead, each episode of the show focused on “issue-oriented” drama.

The Credits Were Rotated Each Week

Issues such as racism, prejudice, and social justice, were addressed during each episode and that was a big risk because the network didn’t know how each show would be rated.

If you closely watch the opening sequence you will quickly notice that the order of the actors’ names were swapped out so nobody always had top billing on the show 100% of the time.

Ponderosa Ranch, Incline Village, Nevada

As previously mentioned, the four main actors were considered equal stars and that was a carefully monitored part of the show.

In 1967, Bill and Joyce Anderson realized that many tourists visited the eastern side of Lake Tahoe in search of the Ponderosa. The couple decided to make money off the Bonanza phenomenon by building a theme park at Incline Village, Nevada. They even recreated the Cartwright’s ranch house.

A Bonanza Theatrical Release?

Portions of the show were even filmed at the park. It remained in operation until 2004.

Bonanza actually had a theatrical release — in Mexico. The episodes “Ride the Wind: Part 1” and “Ride The Wind: Part 2” were given a full release in theaters in Mexico.

Saturday Night Nearly Killed the Show

The episodes were combined and renamed “Jinetes del Viento.” There were no other theatrical releases of the Western TV show.

When the show started on Saturday nights it seemed doomed. The series was targeted for cancellation but given one final chance when it was moved to Sunday nights at 9:00pm.

Michael Landon Wore Heels While Filming

By the mid-1960s ratings had skyrocketed and it reached #1 nationwide. Not bad for a show that barely made it past one season and then went on to finish 14 years of filming.

Michael Landon wasn’t exactly short at 5’ 9” but that didn’t stop him from wearing heels on the set of Bonanza. Several sources claim that his new shoes added a few inches to his stature.

Landon Joked About All the Female Deaths in the Series

Adding height to an actor or actresses appearance isn’t something new and the technique is still used to this very day.

Michael Landon thought it was funny that so many females that showed up on the show would end up dead or mysteriously leaving town. It got to the point where he once joked that the Cartwrights “had to be careful or their horses would trip over the graves” of the past female characters.

First Globally Accepted TV Series

Maybe not the most tasteful joke but it was right on point.

Bonanza wasn’t just a massive success in the United States, it was also the only show to air in every nation on the planet that had an available TV station. That’s a claim that even today’s most advanced connected internet streaming channels like Netflix can’t touch.

The Show Skyrocketed Michael Landon's Success

Bonanza was truly the first globally accepted TV series.

Michael Landon became a massive star thanks to his starring role on Bonanza. He owns the claim to be the only actor to have three TV shows to run consecutively for at least five years.

There Are Three Reunion Movies

He starred in “Bonanza (1959-1973)”, followed by “Little House on the Prairie(1974-1983)” and finally “Highway to Heaven (1984-1989).”

Because of Bonanzas continued success in syndication, the show continued to broadcast new TV specials even decades after the show went off the air. Those TV features included Bonanza: The Next Generation (4/20/1988), Bonanza: The Return (11/28/1993), and Bonanza: Under Attack (1/15/1995).

The End of the Stupid Father Era

It was a truly groundbreaking show and viewers continued to enjoy it for a long-time after the final episode aired.

Before Bonanza debuted in 1959 there was a common theme among TV shows. The men played bumbling morons who could only support their family with the leadership of their wives.

Even The Show's Theme Song Was a Hit

Creators wanted to make sure that Ben Cartwright was a loved and respected father figure who was working hard to support his family and give his children a good life. The idea worked and soon teenage boys all over the country were writing to the show’s studio to say they wanted Ben to be their father.

The show’s theme song was written by Hollywood songsmiths Jay Livingston and Ray Evans. They had many top movie hits of the 1940s and 1950s, and their theme even reached No.

Bonanza Reruns Were Under the Title Ponderosa

19 on the hit parade in 1961. You know your show is successful when its theme song can become a popular hit on local radio.

During the summer of 1972 Bonanza was still being aired on Sunday nights. To ensure that new episodes were not confused with reruns, from 1967-1970, the show aired on Tuesday nights at 7:30 pm under the title Ponderosa.

The Show’s Premise Was The Result Of David Dortort Writing An Episode Of ‘Fireside Theater’

The show, as ratings fell, eventually filled the same time slot with new episodes on Tuesdays.

Series creator and producer David Dortort had a spark of genius for the show when he was writing an episode of Fireside Theatre in 1953. He came up for the idea that would eventually become Bonanza while writing the episode titled Man of the Comstock.

Big Name Stars Were Avoided

He ran with the idea and it paid off with a TV show that lasted for 14 years.

Producers on the show were so certain that the newer medium of color TV was about to produce a new generation of stars that they decided not to cast a bunch of well known actors in the show’s leading roles.

The Show Was Full Of Musicians Who Released Albums

That decision paid off and before long the entire cast of the show were huge international stars.

Did you know that all four Cartwrights sang on the 1964 album Christmas at the Ponderosa? Greene even released a single titled “Ringo” that was a huge hit in the US and Canada.

Truly Equal Billing

Greene also sang the theme song to Bonanza. It has gone on to become one of the most recognizable and popular TV theme songs of all time.

Did you know that all four Cartwrights sang on the 1964 album Christmas at the Ponderosa? Greene even released a single titled “Ringo” that was a huge hit in the US and Canada. Greene also sang the theme song to Bonanza.

Lorne Green Was A Music Star, Too

It has gone on to become one of the most recognizable and popular TV theme songs of all time.

Source: metv

Did you know that all four Cartwrights sang on the 1964 album Christmas at the Ponderosa? Greene even released a single titled “Ringo” that was a huge hit in the US and Canada. Greene also sang the theme song to Bonanza.

‘Bonanza’ Means Exactly That

It has gone on to become one of the most recognizable and popular TV theme songs of all time.

Source: metv

The show was named Bonanza after its real world counterpart, a slang term used by miners to describe a large mineral deposit, synonymous with “jackpot”. An actual bonanza was discovered close to the Cartwright’s ranch, the famous Comstock Lode.

Those Costumes

Source: metv

From season 4 to 14, the characters on the show only wore one set of distinctive outfits. Not only did this make the costume budget easier to swallow but also made for easier editing in the event of re-shoots.

'Bonanza' Almost Got Cancelled … Like Immediately.

Source: metv

Bonanza’s competition (Perry Mason) proved to be so powerful, that NBC was tempted to cancel the cowboy show. However, Bonanza was one of the earliest shows to be filmed in color, so it provided temptation for people to buy color TVs like the ones sold by NBC’s parent company RCA.

Dan Blocker Died Before The Show Finished

Source: metv

Dan Blocker, a.k.a Hoss, succumbed to a pulmonary embolism during a failed gall bladder surgery. The producers found themselves incapable of replacing the gentle giant so Hoss left the series, drowned trying to save someone’s life.

Oh That Michael Landon

Source: metv

Michael Landon (Little Joe) was so committed to the role that he even began writing and directing episodes of the show. However, apart from being extremely difficult to work with, he was reportedly the reason that no new major characters were admitted to the cast.

Lorne Green Is One Of America’s Favorite Tv Dad’s

Source: metv

One of the show’s producers, David Dortort was appalled at the way American fathers were represented in the media, so he made his series an hour long to better portray the kind, caring father that men should strive to be.

Dan Blocker, Almost Mash Star

Source: metv

Blocker was one of Robert Altman’s top choices for an unknown lead role in MASH. Unfortunately for Blocker, the film’s producers refused to give Altman permission to cast the actor.

Mark Twain would have been the Cartwright's neighbor.

Source: metv

Samual Clemens lived in Virginia City, Nevada, in the 1860s. He arrived in the city to mine silver, but eventually worked for the newspaper Territorial Enterprise.

It was one of the final victims of the 'Rural Purge.'

It was there he adopted the pen name Mark Twain.

Source: metv

In the early 1970s, the networks canceled a slew of rural-themed shows to make way for more urban-centric programming. Bonanza was no exception, although it remained on the air after the initial purge in 1971. Bea Arthur's Maude finally took down Bonanza in 1973, when the Western was moved to a timeslot opposite the All in the Family spinoff.

Lorne Greene was also known as "The Voice of Doom."

The only show to last longer was Gunsmoke, which was canceled in 1975.

Source: metv

The Canadian actor was originally a radio announcer for the Canadian Broadcasting Company during World War II.

Dan Blocker broke records as a baby.

His official nickname was "The Voice of Canada," but his booming voice and his role delivering stressful news about the war lead people to give him the nickname "The Voice of Doom."

Source: metv

The hefty actor weighed 14 pounds when he was born on December 10, 1928, making him the largest baby born in Bowie County, Texas. The record still stands to this day.

Blocker founded the Bonanza restaurants.

Source: metv

Not only is the popular buffet chain named after the show, it was founded by one of its cast members. Blocker started the chain in 1963, which eventually boasted 600 locations by 1989. Ponderosa restaurants started in Canada in the early 1970s and expanded to the United States in the 1980s.

It was the first show to address the death of a young male character.

Today, both chains are owned by the same company.

Source: metv

When Blocker died in between the show's 13th and 14th seasons, the producers had no choice but to address the death of the character. The sentiment at the time was no one could fill Blocker's shoes to portray Hoss Cartwright.

Michael Landon got his name from an unusual source.

It was the first time a television series killed off a major young male character.

Source: metv

Born Eugene Maurice Orowitz in 1936, Landon picked his stage name from a phone book.

They have a Christmas album!

Source: metv

The holiday season may have just passed, but remember to put this on your playlist for next year. In 1964, the four Cartwright cast members came together to release Christmas at Ponderosa.

The series was almost canceled after its first season.

The festive album features Christmas staples like "Deck the Halls" and "Jingle Bells."

Source: metv

Because the long-running Western faced off against Perry Mason during its first season, it wasn't among the top 30 shows in 1959-1960. However, NBC decided to keep the show because it was one of the first to be broadcast in color. A time slot change after the show's second season caused Bonanza to rise in the ratings, eventually becoming the No.

They wear the same outfits for a reason.

1 show from 1964 to 1967.

Source: metv

Have you ever noticed how the characters' clothes don't change from episode to episode? From the fourth season onwards, the Cartwrights wear the same outfits like cartoon characters.

The standardization was made to make it easier to reuse stock footage for action sequences and to make it easier to duplicate the wardrobe for the stunt doubles.

Source: metv