For extensive background on E. Clemens Horst’s importance to the West Coast hop industry, see Peter Kopp’s 2016 book Hoptopia, subtitled A World of Agriculture and Beer in Oregon’s Willamette Valley.
Kopp authored earlier an academic thesis (2012) on the subject which is most useful as well. However, he does not, as the titles of his studies suggest, explore Horst’s planting in California very far. I could find no reference to Saazer Seedless, in particular.
Possibly there are California hop histories that examine this, although I have not been able to trace one.
Another point: in British Columbia, Canada of the mid-20th century, substantial hop acreage, especially in the Fraser Valley, was devoted to hop production. I referred to this earlier when discussing National Breweries Limited in Quebec of the 1940s.
Its annual reports state hops were sourced from this region, indeed as a matter of patriotic pride, or putting it another way, as a selling point for consumers who believed in “buying Canadian” .
The English cultivars Golding and Fuggle were grown – noble varieties as the term is understood today – and a few other varieties. They apparently retained much of their English character, at least according to the 1940s brewing text of British brewing scientist Lloyd Hind.
The component breweries of National Breweries at the time, including Boswell, Dawes, and Dow, mainly produced ale, so they were natural customers for such hops.
The B.C. hop industry petered out by 1997, however. It was not able to compete, à la New York State, with lower-cost, large-scale production in the United States, European Continent, and Asia.
It has been said as well that with increasing, trans-national concentration of mass-market brewers in the ’70s and ’80s, they tended to buy hops from sources familiar to them in Europe and the United States.
That is, loss of Canadian brewing independence did not favour Canadian hop production. Of the mass-market brewers only Moosehead is still fully Canadian-controlled, and it is smallest of the “majors”.
A U.S. Golding is raised today in Oregon, derived from Golding rhizomes procured in the ’90s from the John Haas farm near Chilliwack, B.C. (closed in 1997). See details in this website.*
Currently, as in California, there is restoration of hop production in B.C., with craft brewers in the front line of customer ranks. There are at least 30 hop growers in the Province, according to the last figures I saw.
For further background on the resurgence of B.C. hops, see the website of the B.C. Hop Growers Association.
*The Fuggle had long been grown with good success in Oregon, as well, and more latterly Washington State. It was largely replaced by a derivative, Willamette.