Sanvatalia procumbens Creeping zinnias are not true members of the Zinnia genus but appear similar enough to share a common name. Brought to the United States from Mexico in 1798, Creeping Zinnias became popular due to their diminutive height, pretty ¾ inch sunny-yellow flowers, and spreading habit. Very productive, excellent for borders!. 8-10 inches. Will flower continuously throughout the second half of summer.. Full sun. Annual. 25+ seeds.