Plunket, Katharine (1820–1932), botanical and landscape painter, was born 22 November 1820 at Kilsaran rectory, Co. Louth, the eldest of five daughters of Thomas Span Plunket (qv) (1792–1866), protestant curate of the parish, later bishop of Tuam, Killala, and Achonry, and 2nd baron Plunket, and Louisa Jane Plunket (née Foster) (d. 1893), daughter of John William Foster (1749–1809), collector of the port of Drogheda and MP for Dunleer (1783–90), first cousin to John Foster (qv), last speaker of the Irish house of commons; Katharine was first cousin to William Conyngham Plunket (qv), 4th baron Plunket and archbishop of Dublin. From young womanhood she travelled extensively in Ireland, Britain, and the European continent, and painted landscapes and wildflowers in many widely dispersed locations. She was briefly embroiled in the so-called ‘war of Partry’ on her family's Co. Mayo estate, arising from the efforts of her father, a proselytising evangelical, to induce the children of catholic tenants to attend protestant mission schools; during her father's absence from the area, she thrice brought the catholic parish priest, Patrick Lavelle (qv), to court over a row arising from an allegedly sectarian-based eviction, but failed to obtain a conviction (1862). Resident at Ballymascanlan house, near Dundalk, for many years she also kept a London residence at 64 Eaton Pl. For a short period (1881–6) she exhibited watercolours of landscapes in the Alps and elsewhere at the Society of Women Artists in London, some of which entered private collections. In 1903 she presented to the Dublin Museum of Science and Art (latterly the National Museum of Ireland) a bound leather volume of botanical paintings executed over many years in collaboration with her sister Frederica (d. 1886). Labelled ‘Wild flowers, painted from nature’, the volume comprises exactly 1,200 watercolour illustrations of petaloid plants, each executed on tinted card paper, mounted eight to the page, and arranged by biological family, genus, and species. As the pieces are unsigned, attribution of individual paintings to one or the other of the sisters is problematical, though some which are dated after Frederica's death are obviously the work of Katharine. Though the artistic quality varies considerably – the rich colour, but limited palette, best serves the more brilliantly hued species, and there is a general lack of a sense of three-dimensionality – the corpus is of considerable scientific interest, being botanically correct, sensitive to the character of each species, and allowing for comparison of related species. The geographical range is considerable, including numerous locations in Ireland, Britain, and several European countries (especially Switzerland), thus representing the spectrum of western European flora; there is a special feel for flowers of continental pastures, and of the high Alps and Pyrenees. While flower painting, as well as gardening, were fashionable pursuits for ladies of their class and era, the Plunket sisters far surpassed the ordinary practice of the former by the geographical scope, prolificity, and comprehensiveness of their achievement. Custody of the volume was transferred in 1970 to the herbarium of the National Botanic Gardens, Glasnevin, Dublin. A monograph by Mary J. P. Scannell and Christine I. Houston (1985) includes a biographical note on the artists, a description of the volume, and a comprehensive catalogue of the paintings.
Plunket supervised a large garden at Ballymascanlan, and was a frequent prizewinner at local horticultural shows. Largely confined to her bedroom for her last ten years, she had the newspapers and a bible chapter read to her daily, and would occasionally be carried on a chair around her gardens. She visited the 1931 Dundalk show, where she won the Fortescue bowl for best blooms, and presented the show committee with a silver bowl for competition. She saw the centenary (21 September 1932) of the death of the Scottish novelist Sir Walter Scott, with whom she was thought to be the last living link, having sat on his knee at age 5 when he visited her grandfather's house while holidaying in Ireland in 1826. Reputed to be the oldest woman in Ireland, shortly after breakfasting as usual she died on 14 October 1932, thirty-nine days short of her 112th birthday.