Loki Schmidt, who has died at the age of 91, following complications after an operation, was a leading conservationist and the wife of the former German chancellor Helmut Schmidt. She was loved in private and public alike for her modesty, down-to-earth nature and defiance of protocol, characteristics which were given expression in her bestselling autobiography Auf dem Roten Teppich und Fest auf der Erde (On the Red Carpet and Feet on the Ground, 2010). She and her husband, avid smokers since their childhood, were well known for lighting up in public places well after the smoking ban was introduced. She often said that her love of nature had removed for her the fear of dying. "It's a consolation that nothing in the earth's cycle is ever really lost," she said.
The long and happy 68 years of marriage the Schmidts enjoyed both inspired and moved the German public, who seemed to take an increasing interest in them the older they got. As many perceived it, they had attained a state which many only dream of: a lifelong, loyal partnership where respect for each other and their individual personalities was uppermost. They had known each other for more than eight decades, first meeting at school as 10-year-olds. At a birthday party at the Schmidts' house in 1929, Loki left her hat behind. Helmut was told to take it to her and was struck by her modest surroundings: "The pathetic nature of the small two-room flat in the back courtyard of the building … dark but full of children and adults, which shocked me deeply." A friendship developed and from that a deep love and in 1942 they married.
Their first child, a son, Helmut, died when he was seven months old. They had a daughter, Susanne, two years later. Loki said she only ever remembered having one blazing row with her husband and, although she'd forgotten the reason for it, recalled throwing a wet dishcloth at him. "It was prior to monetary reform and I couldn't afford to throw anything that would break," she said.
She described life as the wife of the Social Democrat chancellor as tough, at the same time as enjoying it to the full, especially the foreign travel. One of the most testing times, however, was when the activities of the far-left urban guerilla movement the Red Army faction, were at their height. She recalled making the decision with her husband during a late-night stroll through the park at the back of their Bonn apartment that if either of them were kidnapped by the gang, they would not give in to any of their demands. "The following day we put it in writing and after that, both of us felt rather better," she said.
She was born Hannelore Glaser in Hamburg to an electrician father and a seamstress mother, and her life and public profile was very much shaped by her husband's time in office, between 1974 and 1982. But the former schoolteacher – who went into teaching only because her parents could not afford the fees needed for her to take up a degree in biology – was never short of her own passions and interests or intentions to follow them.
She became involved in nature protection, particularly the fight to save endangered plants, admitting with glee that she had "shamelessly taken advantage of my husband's name" to push her cause. Her work, which included several books on botany and gardening, earned her international recognition and numerous prizes.
During a research trip to Mexico in 1985, she discovered a previously unknown pineapple plant which was subsequently named after her: Pitcairnia Loki-Schmidtii. A Tunisian orchid and a new strain of dahlia also carry her name. On meeting Emperor Hirohito of Japan in the 1970s, she brought up the subject of rare fish breeds with him, despite having been instructed in advance that only he was allowed to determine the direction of conversation. "The very old emperor then proceeded to tell her how proud he was that his son had just discovered a new breed of fish in Tokyo Bay," Helmut Schmidt recalled.
Last Thursday she had been due to present the "Flower of the Year" award, at an event she had hosted for over 30 years, to the Narthecium.
She is survived by her husband and daughter.