The distribution of Ulocladium botrytis is fairly broad, wherein it has been found worldwide in areas of Europe, North America, Egypt, India, Pakistan, and Kuwait. It is often isolated from soil, where it is a common contaminant; however, U. botrytis also grows on rotten wood, paper, and other textiles or on dead herbaceous plants. It also heavily favors growth in damp indoor environments. This fungus has been found growing on deciduous alder trees (Alnus) which belong to the birch family Betulaceae. Trees in this family include the American green alder and the mountain alder. U. botrytis can also be found growing on the evergreen coniferous tree genus Pseudotsuga of the family Pinaceae; different trees include the Douglas fir and the big-cone spruce. In addition, this fungus can grow on the flowering plant genus Sphaeralcea of the mallow family Malvaceae; plants include the desert hollyhock and the prairie mallow. A previously conducted study also isolated a unique strain of Ulocladium botrytis, strain number 193A4, from the marine sponge Callyspongia vaginalis. Another independent study found seed-borne Ulocladium botrytis from pearl millet (Pennisetum typhoides).
