'Roses' was US geographical rather than operational codename, changed to 'Truculence' in February 1943 and later still to 'Acid' and finally 'Suxe', for Efate island in the New Hebrides islands group (1941/45).
The New Hebrides islands group lies to the north-east of New Caledonia island and to the south-east of the Solomon islands group, and is a chain of about 83 mountainous and jungle-clad islands, 550 miles (885 km) long with a total land area of 4,706 sq miles (12189 km²), aligned generally on a north-north-west/south-south-east axis. The chain splits in its northern half, and is therefore ultimately of a Y shape. The wet season is from November to April, when typhoons are possible, but the islands are wet and humid right round the year round, and malaria is a serious problem.
On the outbreak of the Pacific War, the islands were very sparsely populated, the largest settlement, Port Vila on Efate, having just 1,500 inhabitants in 1942, and the group’s overall population may have been in the order of just 40,000 persons in 1941. The islands were jointly controlled by the UK and France under a condominium agreed in 1906. The resulting duplication of effort did not help the quality of administration of an area lacking almost any economic significance before the war. Copra was the only valuable product, and the French imported 1,000 indentured labourers from French Indo-China. The British and Australians were forbidden by their governments to bring in labour, and their respective administrations came to outnumber those being administered.
As war loomed, the Australians began to raise a New Hebrides Defence Force in 1941: this eventually grew to a strength of more than 2,000 men, most of them from Malekula island.
During the 'Watchtower' campaign on Guadalcanal, the Allies established a major forward base at Espiritu Santo and a second base at Efate.
Efate is roughly circular with a diameter of about 35 miles (56 km) and an area of 347 sq miles (900 km²). The island is mountainous in its north-western region, with a maximum elevation of 2,123 ft (647 m) at Mt McDonald, while its southern part is flat and well-watered, allowing the cultivation of several types of crops, including copra. The island possesses a good anchorage at Havannah Harbour in the north-west, but this remained undeveloped as a result of its isolation from the rest of the island by the north-western mountains, and there were a few commercial piers and other primitive port facilities as well as a seaplane ramp at Port Vila in the centre of the west coast. The population of some 2,400 persons included about 400 Europeans.
With the fall of France to Germany in June 1940, the resident at Efate declared for the Free French and was promptly dismissed by the high commissioner on New Caledonia. The resident ignored his own dismissal, and when a referendum in September came out in favour of the Free French movement, he briefly relieved the high commissioner on New Caledonia.
Located some 300 miles (485 km) to the north-east of Nouméa on New Caledonia, Efate was a good location for an Allied base to cover the vital supply route from the US west coast to Australia, and as early as 18 March 1942 Admiral Ernest J. King, the US chief of naval operations, recommended its development, in the following month also suggesting that the base could be a starting point 'from which a step-by-step general advance could be made through the New Hebrides, Solomons and Bismarcks': this was essentially how the campaign in the South Pacific progressed in 1942/43.
Allied forces started to reach Efate on 18 March 1942, the first being 500 men of the Americal Division on New Caledonia. These were reinforced on 24 May by the ground echelon of VMF-212, the 4th Marine Defense Battalion, and the 24th Infantry, the last an African-American unit. The airfield at Port Vila had a 6,000-ft (1830-m) runway ready for service by the time the 'Watchtower' campaign on Guadalcanal started in August 1942.
Flying boats operated from Havannah Harbour, to which a road was constructed in 1943, and a 3,000-ft (915-m) airstrip was completed at Havannah Harbour in September 1942 and a 6,000-ft (1830-m) runway at Quain Hill in January 1943.
The base had outlived its operational utility by a time early in 1944, however, and was closed in February 1946.