Ask Mr. Smarty Plants

We presume you are referring to a bloom stalk, rather than what would be a trunk on a tree? We are always a little puzzled to get questions about what we consider to be desert or semi-desert plants from the Mid-Atlantic area of the United States. We always like to know what plant we are talking about, and there is exactly one yucca, Yucca filamentosa (Adam's needle), that grows naturally in Ohio. The most complete discussion of this plant was found in this Ohio State University article on the plant. Another good article is from Dave's Garden Forum. You will be interested in reading the comments, most of which come from states as least as different from deserts as Ohio. Notice in particular the comment that one person's yucca only bloomed every 3 to 5 years, possibly because of the colder climate.

Having grown up where yuccas are virtually roadside weeds, in the Texas desert, we can tell you from experience that the bloom stalk begins by looking like some leaves wrapped around each other deep in the center of the plant, slowly growing up and beginning to unfurl. It begins to lengthen and rise in a stalk out of the plant, blooming a creamy white during July and August. Until you see that irregular clump at the center of the plant, you really can't tell if it is going to bloom or not.