Morton was a journalist who founded Nebraska's first newspaper. On January 4, 1872, he first proposed a tree-planting holiday to be called "Arbor Day" at a meeting of the State Board of Agriculture. The date was set for April 10, 1872. Prizes were offered to counties and individuals for planting properly the largest number of trees on that day. It was estimated that more than one million trees were planted in Nebraska on the first Arbor Day.
Arbor Lodge, Morton's home in Nebraska City, together with an arboretum and extensive landscaped grounds, is a state historical park and is open to the public. His adjacent farm is now 'Arbor Day Farm,' run for the benefit of the "National Arbor Day Foundation' in Nebraska National Arbor Day is celebrated on the last Friday in April of each year. Additionally, many states hold their own Arbor Day celebrations.