Thanks to Gillian, you had already discovered the National Collections of Crocus held by Myddleton House in Cambridgeshire and David Stephens in Surrey.
This time, I visit another National Collection of Crocus in Surrey, at RHS Wisley. Established in the early days of Plant Heritage’s existence (1981), it holds an impressive 113 species and 88 cultivars. The pots are displayed in the Alpine House during their peak flowering periods (Spring and Autumn):
In the wild, crocuses are distributed from the Mediterranean region and Middle East, all the way up to China. Many species have a limited distribution which can make them vulnerable to habitat loss, like Crocus sieberi subsp. atticus (an endemic of the Attica region of Greece):
The genus was introduced to England in the late 16th century, and soon became a garden favourite. Victorian horticulturists like the famous E A Bowles raised a great number of cultivars. Unfortunately many have disappeared from the trade, and according to results of the Threatened Plants Project, 150 cultivars are considered to be “threatened in cultivation” in the UK. Thankfully over 40 are safely held at RHS Wisley, such as this stunning Crocus korolkowii ‘Dark Throat’, last listed in the Plant Finder in 2006:
Some crocuses like the early-flowering C. chrysanthus ‘Gypsy Girl’ are also grown outside, in the Centenary Crevice garden:
Here are a few more species and cultivars from the National Collection (there’s even a cultivar named ‘Wisley Wine’!):
Crocuses are flowering now at Wisley, so if you are planning a visit, don’t forget to have a look in the Alpine House…