Thaddeus Clapp (1811-1861) was the noted hybridizer of the "Clapp's Favorite" pear, a cross breeding of the "Bartlett" pear and the "Flemish Beauty" pear. From 1840 until his death Clapp was "celebrated among fruit growers for his theoretical and practical knoweledge, and obtained many premiums for choice varities and fine samples of fruit."
Born in Dorchester, the son of William Clapp (1779-1860) and Elizabeth Humphreys Clapp, he was educated at the academy of Hiram Manley before entering Harvard College, being graduated in 1834; he attained a distinguished rank with "the second honors of his class" and delivered the salutory oration in Latin. He was to receive his master of arts in 1838, and though he had taught at a private school in Brookline, his ill health precluded full time employment. During the 1840's he served as a member and secretary of the Dorchester School Committee (Dorchester remained an independent town from Boston until 1870.) In 1838 he served as tutor to the family of William T. Palfrey in Franklin, Louisiana thinking that the warm climate might be beneficial to his health. The Palfreys were from Boston, and were probably acquainted with his family, but he returned shortly therafter. He returned to his family home in 1840, a large Federal house built by his parents at 195 Boston Street and called the "Mansion House." His father was a well to do leather tanner with tanneries on his extensive estate that stretched back to South Bay and which had been in the family since the seventeenth century.
After his return to Dorchester, Thaddeus Clapp "engaged in horticultural and pomological persuits, which he continued until the winter of 1860." During that time he and his brothers Lemuel and Frederick Clapp hybridized many pear seedlings which were quite successful and the names of which were given to new streets that were cut through the former Clapp Estate; the new streets were named Mayhew, Mount Vernon, Harvest, Dorset and Bellflower to perpetuate the early hybrid pears, but it was his pear seedling "Clapp's Favorite" that became reknowned as it was an early ripening fruit, in an age when fresh fruit was thought to ensure continued good health. So successful was this pear seedling that the the Clapp's Favorite pear, was greatly desired by the Massachusetts Agricultural Club, which wished to name it after Marshall P. Wilder, and to disseminate it for general cultivation. They offered Mr. Clapp one thousand dollars for the control of it, but the offer was politely declined. For two decades Clapp continued his horticultural persuits and was an active member of the Massachusetts Horticultural Society and the Norfolk Agricultural Society. He was said to be of a "most amiable disposition and led a life of unspotted integrity. In 1873, over a decade after Clapp's death, the "Clapp's Favorite" pear was awarded the Wilder Medal in 1873; this medal is awarded to individuals or organizations for distinguished service and contributions to the advancement of pomological science and for outstanding fruit varieties.
When he died, his widow Mary H. Dustin Clapp buried him at Forest Hills Cemetery. His white marble headstone has a bas relief of the celebrated "Clapp's Favorite" pear and that of his wife a shorn sheaf of wheat.