A century ago, growers were also eager for broccoli varieties that could be harvested later into spring and early summer.

Some of the finest strains of late broccoli, however, are not in commerce, being in the hands of market-men, who have been selecting and re-selecting the stock for the last two or three generations, and from whom it is impossible to beg or buy even a single seed. In course of time, however, these will doubtless pass into the seeds men’s hands, when several late strains, later than anything at present in commerce, will be added to our list of useful varieties.
— F. W. Hammond. Pilgrim’s Hatch, Essex.
In The Garden, February 1917.

This article is about white broccoli, which was raised in England in the late 19th and early 20th century. It looked virtually identical to cauliflower but was cold hardy and raised for cold-season harvest. It was typically planted in the spring and harvested in either late fall or early the following spring. Biennial types headed and were harvested in the spring, but had little heat tolerance. Growers eagerly wanted late varieties that could be harvested in May and still look good.