Eryngium x zabelii ‘Violetta’ (Violetta Sea Holly)

To my mind this is one of the top ten garden perennials. It was first grown in English gardens in 1913 and by the late Dennis Norgate at his Trentham Plant  

Farm for more than fifty years from the 1950s until the early part of this century. I grew it for many years but like so many old perennial varieties which are grown from cuttings and division, ‘Violetta’ lost vigour and suffered from virus and other problems. I stopped growing it a couple of decades ago because I couldn’t produce good quality stock.

Happily modern technology has come to the rescue and this gorgeous plant is now being produced by tissue culture, having been cleaned of the disease problems which plagued it in the past.

One of the ways to inactivate plant viruses is by heat therapy. The plant is kept at a temperature of 38 degrees centigrade for a prolonged period. The plants which survive this treatment are hopefully freed of the pathogen. The subject will be tested for the virus infection and if clear the clean tissue is placed into a laboratory and good quantities propagated.

Through this long and laborious process Lambley can now sell good clean stock of the fabulous Eryngium ‘Violetta’.