Sequoia sempervirens
In 1951, the couple founded the sequoia farm "Sequoiafarm Kaldenkirchen" using "Sequoiadendron giganteum" seeds sent from the USA. In 1953, with support from the German Research Foundation 1500 two years copies of the Giant Sequoia tree next to coastal redwoods maintained "Sequoia sempervirens" and other species. A research objective was to examine the possibilities for the introduction of these trees in the German forestry. Illa Martin tried to make the forest floor a correspondingly diverse area of flora, containing for example, the American wild ginger "Asarum caudatum". Today, the Sequoia Farm is a famous arboretum with over 600 tree species and contains the 1953 scale "Sequoia sempervirens" grove next to the Sequoia sempervirens deposits in national forest timber castle one of the very few larger coastal redwood holdings north of the Alps.