Pear trees had a reputation of taking about twenty years to bear fruit, but of lasting over a century. The proverb “plant pears for your heirs” has been cited in print since at least 1842, but is probably much older. Although new varieties of pears bear fruit sooner than twenty years, the proverb is still frequently recalled.
 
 
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12 February 1842, The Gardeners’ Chronicle, pg. 109, col. 3:
HOME CORRESPONDENCE.
On Planting.—The root-pruning of Mr. Rlvers has given the lie to the horticultural distich of
 
Plant Pears
for your heirs,
 
and the octogenarian may now “order his rows” with fair hope of reaping a goodly crop in his own lifetime; ...
 
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Annual Report of the Indiana State Horticultural Society
Indianapolis, IN: Alexander H. Connor
1869
Pg. 24:
Mr. Ragan said — Mr. Weinberger had demonstrated that the old adage, “Plant pears for your heirs,” was not correct. He has thirty-five varieties, planted in 1864 on sandy loam, fifteen feet apart, that now are bearing finely.
 
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22 December 1894, The Gardeners’ Chronicle, pg. 747, col. 3:
There is an old saying, often quoted, “Plant Pears for your heirs;” and no doubt the same would be applied to Apple-growing too, if there happened to be a rhyme to suit it, but this, like many another specimen of ancient wisdom, has nowadays become a fallacy.
 
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English Proverbs and Proverbial Phrases
By William Carew Hazlitt
London: Reeves and Turner
1907
Pg. 361:
Plant pears for your heirs.
A proverb which no longer holds true, since pears are now made to yield well after a few years; but formerly the tree was, it appears, of particularly slow growth, though, according to the French Gardener, 8vo, 1658, the varieties at that time in cultivation were extremely numerous.
 
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The Drunken Botanist:
The Plants that Create the World’s Great Drinks
By Amy Stewart
Chapel Hill, NC: Algonquin Books
2013
Pg. 30:
Pear trees also grow slowly and bear fruit later in life, making them a long- term investment rather than a quick crop, which is why farmers say, “Plant pears for your heirs.”
     
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I Love New York:
Ingredients and Recipes
By Daniel Humm and Will Guidara
New York, NY: Ten Speed Press
2013
Pg. ?:
At Migliorelli Farm. an old farming adage still applies: “You plant pears for your heirs.”
 
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mulch
‏@mulchtweet
‘Grow pears for your heirs’, the saying goes. Good Irish Times article about speeding up the process… http://fb.me/1JtY1rm4S
6:55 AM - 29 Sep 2014
 
Stroud Life (UK)
Keeping it Local with Stroudco Foodhub: Toasting manager’s new job with glass of perry
By Stroud Life |  Posted: April 07, 2015
(...)
Perry pear trees can live for several hundred years and are still productive well into their third century leading to the old adage “plant pears for your heirs”. Perry trees can grow to the size of an oak - the largest recorded was a tree at Holme Lacy which still partly survives. It covered three quarters of an acre and yielded a crop of five to seven tons in 1790.