Johann Frantz (or Franz) Drege was a younger brother of Carl Friedrich Drege*. In 1809 he went to Goettingen where he trained as a horticulturalist, and was afterwards employed in the botanical gardens of Munich, Riga, Berlin, and St Petersburg. On the advice of his brother Carl, who resided in Cape Town at the time, he came to the Cape in March 1826, accompanied by another brother, Eduard, who was a watchmaker. After J.F. had collected plants in the vicinity of Cape Town for some time he undertook his first long collecting trip. Leaving Cape Town in August 1826 he travelled to the Great Karoo and for eight months collected plants in the Nuweveld, Winterveld, Koup (between the Swartberg and Newveld Mountains) and Kamdeboo. On his return he settled at Paarl, where Carl had a pharmacy, undertaking short collecting trips in the Western Cape for the next two years. He and Carl then decided to travel and collect professionally together, with Carl concentrating on zoological specimens and J.F. on plants. Their first journey, starting in May 1829, took them along the Swartberg eastwards to the upper valley of the Sunday's River, as far north as the vicinity of present Middelburg, and then down to the Fish River valley and Albany, with a visit to the Moravian mission station at Enon. At Uitenhage they met J. Brehm* and collected with C.F. Ecklon*. They returned to Paarl via the Langkloof and Swellendam in February 1830. In June the two left on their second journey, to Namaqualand. It took them as far north as the Orange River near its junction with the Fish River in September, and down to its mouth. They returned to Paarl with a large collection in January 1831.
After replenishing Carl's stock of medicines (which they used, among others, to barter for specimens) they set off again in July on a journey that would eventually take them to Port Natal (now Durban). On their way eastwards they met the naturalist Carl Villet* who was staying near Plettenberg Bay at the time. Learning that Dr. Andrew Smith* was on his way to Port Natal, the brothers met him in Port Elizabeth in December 1831 and it was agreed that they would join his party. They followed more or less the route of the present main road to the vicinity of Umtata, then went down to the coast and reached Port Natal in March 1832. The Dreges remained in that area to collect while Smith travelled on to Dingane's kraal. J.F. was the first plant collector of note to visit Natal. Leaving Port Natal in April 1832, they returned to Port Elizabeth in July. Further travels in the Eastern Cape followed during July to October. They then travelled north to the Orange River near Aliwal North, returned via Colesberg and Graaff-Reinet, visited Enon again, and reached Paarl in May 1833. Carl left for Europe in July that year, but J.F. stayed a while longer. He made another journey to Clanwilliam, the Olifants River and the Vanrhynsdorp area, from abouth November 1833 to March 1834. Then he too returned to Europe.
J.F. collected plants in South Africa for eight years, in all seasons, more systematically and with greater insight than anyone before him with the possible exception of W.J. Burchell*. He kept meticulous notes of his finds and the sites at which they had been collected, including the altitude above sea level. These notes added greatly to the scientific value of his specimens. His collection was the most comprehensive that had yet been made in southern Africa, comprising some 200 000 dried specimens that represented about 8000 species, many of them (including several genera) new to science. Included were a number of fungi and lichens. One set of specimens went to his friend, Ernst H.F. Meyer, professor of botany at Koenigsberg. Meyer published on two portions of the collection in his Commentariorum de plantis Africae Australoris... (Leipzig, 1835, 1837). The collection enabled him to identify ecologically important species such as heaths and succulents, as well as some phytogeographical characteristics of the Cape, such as the high number of endemic species.
According to Carl's diary, J.F. returned with him to the Cape in 1835. However, J.F. was married in Hamburg in December 1837, so he either stayed in Germany or visited the Cape only briefly. He published a catalogue of the specimens he had for sale, Catalogus plantarum exsiccatarum Africae australofloris... (1837-1939), and made up sets of specimens that were sold to most of the large European herbaria. Various European botanists and mycologists published on the specimens from 1836 onwards. Part of Drege's remaining collection was destroyed by a great fire in Hamburg in 1842. The next year he published his most important work, Zwei pflanzengeographische Dokumente... (Leipzig, 1843-1844), which contains an alphabetical list of the species he collected, with cross references to the collecting localities. In an introduction Meyer divided the Cape Colony into different phytogeographical regions, which he described in terms of their geography, climate and flora, and Drege represented these regions on the first phytogeographical map of South Africa. Meyer's introduction to this work, and his introduction to the Commentariorum, were later translated into English by H. Bolus* and published in a series of articles in the Cape Monthly Magazine from October 1873 to April 1874, and also as a monograph (Cape Town, 1875, 61p). Drege was still offering South African plants for sale after the fire of 1842, for example in Herbarien der suedafrikanischen aussertropischen Flora, zu haben bei J.F. Drege... (Hamburg, 1847, 25p). Also in 1847 he published two papers in Linnaea, one on the localities of the plants collected in South Africa by C.L.P. Zeyher*, the other a comparison between the collections made by Ecklon, Zeyher and himself.
On the basis of his work Drege is recognised as the father of South African phytogeography, and his work has been highly praised by eminent botanists such as H.W.R. Marloth*, P. MacOwan*, and Bolus. He was a pleasant man of outstanding ability, and a meticulous and untiring collector. More than a hundred species of South African plants, as well as the genus Dregia, were named in his honour.