“The best time to plant a tree was 20 years ago. The second best time is now” is a saying that has been printed on many images. Authorship of the proverb is unknown.
 
“Someone remarked that the best time to plant a tree was 30 years ago, and the second best time is now” was printed in The Plain Dealer (Cleveland, OH) on March 19, 1967. “It has been said that the best time to plant a tree was 30 years ago, the second best time is today” was printed in the Ottawa (ON) Journal on March 13, 1969. “‘The best time to plant a tree,’ the men and women of AAN (American Association of Nurserymen—ed.) say, ‘was a long time ago. The second best time is now’” was printed in the Eunice (LA) News on November 6, 1973. “According to one French philosopher, ‘The best time to plant a tree was 20 years ago. The second best time is now’” was printed in the Sunday Plain Dealer (Cleveland, OH) on September 7, 1975. “(South Dakota Gov. Bill—ed.) Janklow used a Chinese Proverb to put the theme in perspective. ‘The best time to plant a tree was 20 years ago. The second best time is today’” was printed in the Spearfish (SD) Star on October 12, 1985.
 
The tree saying was promoted in the 1970s by the American Association of Nurserymen (later called the American Nursery and Landscape Association, and now called AmericanHort). While the saying is often given as a Chinese proverb, no such proverb is known. “One generation plants the trees, another gets the shade” is a Chinese proverb listed on the website The List of World Proverbs. “It takes ten years to grow a tree and a hundred years to cultivate (a generation of) good people” was printed in the book ABC Dictionary of Chinese Proverbs (Yanyu) (2002) by John S. Rohsenow. However, these Chinese proverbs do not appear to be related. 
   
       
AmericanHort     
Our Legacies
AmericanHort was founded January 1, 2014, through the consolidation of the American Nursery and Landscape Association (ANLA) and OFA - The Association of Horticultural Professionals. But that is far from the beginning.
 
The American Nursery and Landscape Association (ANLA) was founded in 1876 as the American Association of Nurserymen, Florists and Seedsmen. With the departure of the florists and seedsmen companies in the early 1880s, the association’s name was changed to the American Association of Nurserymen and has ever since represented the interests of nursery and greenhouse growers, landscape firms, distributors, retailers, and allied suppliers. 
 
The List of World Proverbs
11. One generation plants the trees, another gets the shade.. Chinese Proverb. One generation plants the trees, another gets the shade.
Chinese Proverb
12. The one who plants the tree is not the one who will enjoy its shade.. Chinese Proverb. The one who plants the tree is not the one who will enjoy its shade.
Chinese Proverb
   
19 March 1967, The Plain Dealer (Cleveland, OH), “Negro Help for Negroes Under Way,” pg. 9-A, col. 1:
“Someone remarked,” White (city councilman George W. White—ed.) said, “that the best time to plant a tree was 30 years ago, and the second best time is now. That’s how it is with us.”
 
8 March 1969, Ottawa (ON) Citizen, “Canada better placed in conservation plan,” pg. 20, col. 3:
Addressing the annual convention of the Canadian Wildlife Federation at the Chateau Laurier, Mr. (Jean—ed.) Cretien commented that it had been said that the best time to plant a tree was 30 years ago and the second best time was now.
 
13 March 1969, Ottawa (ON) Journal, “Fish and Game: The Time Is Now” by Phil O’Reilly, pg. 27, cols. 1-2: 
“It has been said that the best time to plant a tree was 30 years ago, the second best time is today. The same is true for conservation. The best time to conserve the habitat necessary for our wildlife would have been 50 or 100 years ago. The second best time is now.”
 
These were just a few of the many interesting remarks made by Jean Cretien, Minister of Indian Affairs and Northern Development, to the delegates attending the annual meeting of the Canadian Wildlife Federation last Friday.
   
11 June 1971, Wisconsin State Journal (Madison, WI), sec. 1, pg. 6, col. 6 ad:
The Best Time to Plant a Shade Tree
...was 30 years ago. The next best time is today!
(The Bruce Company.—ed.)
   
6 November 1973, Eunice (LA) News, “Historical plantings of trees show value of planting now,” pg. 11, col. 3:
“The best time to plant a tree,” the men and women of AAN (American Association of Nurserymen—ed.) say, “was a long time ago. The second best time is now.”
 
16 November 1973, Daily World (Opelousas, LA), pg. 13, col. 2 classified ad:
TIME TO PLANT?
The best time to plant a tree was a long time ago. The next best time is NOW!
Lousiana Nursery
   
7 September 1975, Sunday Plain Dealer (Cleveland, OH), sec. 2, pg. 1, col. 1 ad:
The second best time to plant a tree.”
According to one French philosopher, “The best time to plant a tree was 20 years ago. The second best time is now.”
(Roulston and Company, Inc.—ed.)
 
9 June 1978, State-Times (Baton Rouge, LA), pg. 5-E, col. 1 ad:
The Best Time to Plant a Tree is 20 Years Ago.
The Next Best Time is Now.
(Kelleher garden center and landscape.—ed.)
 
12 October 1985, Spearfish (SD) Star, “Janklow outlines progress in responding to retarded” by Rae Price, pg. 1, col. 1:
(South Dakota Gov. Bill—ed.) Janklow used a Chinese Proverb to put the theme in perspective. “The best time to plant a tree was 20 years ago. The second best time is today.”
 
28 May 1986, Sun Sentinel (Fort Lauderdale, FL), “DOwntown Pompano Renovation Leads New Commissioner’s Goals” by Nancy E. Roman, pg. 3:
But newly elected Commissioner Grey Webb said he would make good his campaign promises to begin planning yet another renovation of downtown Pompano Beach.
(...)
“There’s an old Chinese proverb: The best time to plant a tree is 20 years ago, the second best time is now,” Webb said. “We should have started sooner, but I’m ready to start now.”
   
Google Books
ABC Dictionary of Chinese Proverbs (Yanyu)
By John S. Rohsenow
Honolulu, HI: University of Hawai’i Press
2002
Pg. 138:
It takes ten years to grow a tree and a hundred years to cultivate (a generation of) good people.
     
Google Books
Mobile Broadcasting with WiMAX:
Principles, Technology, and Applications
By Amitabh Kumar
Boston, MA: Focal Press
2008
Pg. XVII:
The best time to plant a tree is 20 years ago. The second best time to plant a tree is today. —African Proverb  
 
Google Books
Leadership for All the Mountains You Climb:
Workbook
By Mark W. Altman M.I.S.
Bloomington, IN: AuthorHouse
2008
Pg. 9:
“The best time to plant a tree was 20 years ago. The second best time is today.” - Gerry Harvieux
     
Google Books
From an Oak to His Acorns:
Essential Lessons for Life
By Douglas Kretkowski
Published by author
2009
Pg. 295:
“The best time to plant a tree was twenty years ago. The second best time is today.” – Chinese Proverb.
 
Google Books
The 360 Degree Leader:
Developing Your Influence from Anywhere in the Organization
By John C. Maxwell
Nashville, TN: Thomas Nelson
2011
Pg. ?:
On the wall in the office of a huge tree farm hangs a sign. It says, “The best time to plant a tree is twenty-five years ago. The second best time is today.”
 
Google Books
Title The Best Time to Plant a Tree Was 20 Years Ago. the Second Best Time Is Now: Daily Sobriety Journal for Addiction Recovery Alcoholics Anonymous, Narcotics Rehab, Living Sober, Fighting Alcoholism, Working the 12 Steps and Traditions. 124 Pages. 6 X 9
Volume 1 of Sobriety Journal
Author Steve Axworthy
Publisher Independently Published, 2019
ISBN 1794002863, 9781794002869
Length 126 pages