Thalictrums
Jennifer Harmer

Thalictrums are members of the wide ranging Ranunculaceae family which we have featured before in this series. Thalictrum is from the Greek thaliktron, the name given by Dioscorides to an unknown plant which may have been of this species. They are usually found in shaded or damp locations, with a cosmopolitan range throughout most of the Northern Hemisphere, southern Africa and tropical South America but it is most common in temperate regions. Over the course of the next couple of months there will be many different forms coming into flower in our gardens.

Thalictrum diffusiflorum Its bluey-lilac flowers are the largest flowers of all the thalictrum family. It has maidenhair fern-like foliage, flowering from June to July and it reaches a height of 60 cm. This plant needs careful placing, ideally in dappled shade and near the front of a border to admire its large flowers.

Some of our other favourites are:

T. aquilegiifolium var. album Named for the foliage which is very similar to aquilegia leaves with lovely fluffy white flowers. This flowers in May-June. T. aquilegiifolium ‘Thundercloud’ flowers a little later and has beautiful, large soft dusky purple flowers.

T. delavayi Abbe Jean Marie Delavay (1838-95) was a French missionary who introduced many notable plants into cultivation. He prepared some 200,000 specimens, each collected and dried by his own hand with the appropriate field notes. He lived in north-west Yunnan for 10 years. He suffered an incomplete recovery from bubonic plague and the loss of his right arm. Most of his specimens were lost due to incompetence in Paris. He was particularly interested in the garden value of his plants. This is a wiry plant, like rich lilac gypsophila with tufts of cream stamens, June-August. T. delavayi ‘Album’. is a more compact plant with white flowers from July to September.

T. delavayi ‘Hewitt’s Double’ This has long been a favourite in many gardens. It has airy sprays of small double lilac flowers in summer, 1 m high, but it does need a free-draining soil in sun. Hewitts were nurserymen at Solihull, Warwickshire, and the famous plant hunter E.H. Wilson served his apprenticeship there.

T. ‘Elin’ is Coen Jansen’s graceful hybrid. It is huge and vigorous (2-3 m) with heads of white flowers from purple buds on tall stems, and sumptuous blue foliage which is dark in spring. It flowers from June to August. However, I moved mine after a couple of years because it was too tall where I had planted it and it has never been so vigorous since that time.

T. flavum ‘Illuminator’ I first saw this thalictrum many years ago, growing in Jane Sterndale-Bennett’s garden. The young leaves are a beautiful soft creamy grey with gold and pink highlights from late winter to spring, February to April and 50 cm in height. It has tight heads of stronger creamy-yellow flowers from June to July and 1.5 m high.

T. flavum ‘Gold Lace’ This is a less well known plant which is grown by Sue Ward. It is an introduction from the Sue & Robbie White’s much missed Hampshire nursery -Blackthorn’s.

Two new thalictrums Sue and I are growing and particularly like are: T. ‘Black Stockings’ which has netted black stems and deep purple flowers to 1 m high and 45 cm wide and T. honanense ‘Marble Leaf’ which has amazing foliage. Each large leaflet is rhombic, red or purple stained and marked with grey, mimicking a begonia. The flowers are fluffy pale lilac and Bob Brown says it is truly continuous from April to November but I have not had my plant long enough to confirm this. It is short, 30 cm in height, and was collected at 1400 m altitude in China.

First published in the Hampshire Group Newsletter, Summer 2009
and subsequently in Cornucopia Issue 27.
© Copyright for this article: Jennifer Harmer

This article was taken from a copy of Cornucopia that was published in 2011. You could be reading these articles as they are published to a national audience, by subscribing to Cornucopia.