Dering's husband died in about 1704, leaving Henrietta a widow with two daughters. In 1705 she married again, this time to Anglican clergyman Gideon Johnston, a graduate of Trinity College, Dublin then serving as the vicar at Castlemore. Two years later, he was appointed by the Society for the Propagation of the Gospel in Foreign Parts to serve as commissary of the Church of England in North and South Carolina and the Bahama Islands. He was also to serve as rector of St. Philip's Episcopal Church in Charleston. The couple's time in the colonies was hard; Johnston was frequently writing the Society to request payment of his salary, which was often delayed, and their lives were further hampered by illness, lack of supplies, and distance from family. In one of his letters to his patron Gilbert Burnet, written in 1709, Johnston mentions that "were it not for the assistance my wife gives by drawing of Pictures (which can last but a little time in a place so ill peopled) I should not be able to live", indicating that Henrietta had again taken up her drawing to augment the couple's income. Another letter, dated a year later, reveals that she had run out of drawing materials and suffered "a long and tedious Sickness". Johnston made one return trip to England, in 1711–1712; her husband, too, returned there once, from 1713 to 1715. He died in a boating accident in 1716, not long after returning to Charleston.