grower

Etymology

grow + -er

noun

1. A farmer; one who grows things.
   He was an orange grower from Florida.
2. Something that grows.
   These flowers are fast growers
   'The Bride' [a snowdrop variety], found in the early Seventies at Foxcote Farm near Cheltenham, was his first discovery. It's a poculiform (cup-shaped) G. elwesii with six pure white petals of the same length. Like many poculiforms […] it's not a strong grower. 7 February 2015, Val Bourne, “The quiet man of the world of snowdrops”, in The Daily Telegraph (London), page G8
3. Someone or something, especially music, that becomes more likeable over time.
   I didn't like the song at first, but it is a real grower.
   Sanctury - the least obvious single but what a grower. When I first heard this track I thought it was rather average. After playing the album several times, this was the one that kept coming into my head throughout the day. 1994, Mr. S.R. Winterton, “Bedtime Stories - The Singles”, in alt.fan.madonna (Usenet)
   […]assimilating some vaguely psych, folk-rock, and other influences into their own twang without losing sense of style and taste: a grower, not a shower (that's show-er, not shower). 2001, Maximum Rock 'n' Roll, Issue 223
4. (slang) A man whose penis increases in size significantly when erect.
   As a man who can best be described as a "grower not a shower", I helped Brent realize that many people in the gay community are concerned in a very adolescent way with their dick size, including me. 1993, Barry Burns, “Muffin on Parade”, in soc.motss (Usenet)
   "Growers" are guys whose penises tend to contract a lot lengthwise when flaccid, while "show-ers" are guys whose penises could be said to merely "deflate" without contracting much in length. 1994, jenster, “Penis Size and other Eternal Questions”, in seattle.general (Usenet)
   His dick, if I remember correctly, is more of a shower than a grower[…] 2003, Austin Foxxe, Three the Hard Way: Tales of Three-way Sex Between Men