How do I know if my sunflowers are annual or perennial? And if they are perennial, what do I need to do so that they come back next year?
Sunflowers…Perennial or Annual
while Most sunflowers are considered annual, its all depending on WHERE you live. for example, Mexican sunflowers ie. tithonia diversifolia, ARE perennial. Unlike another article provider states, they DO grow higher than 6 ft. Mine are 15 feet right now in early October, and are set to bloom within a week or two as the pods are forming in zone 9b, central fla. Unlike the article states, they do NOT germinate well at all. In fact, propagation is accomplished via asparagus size stalks which readily water root. So, best bet if want these, find someone who has them and will share a cutting or two for propagation. Most seeds will rot b4 birds eat them. tithonia diversifolia are often confused with other tithonia varieties that are dwarfed by their exceeding height. The enrich the soil and require NO fertilization whatsoever. The leaves are prone to blight out, but that has No effect on the beautiful blooms which are short lived. Each year they get clumpier, but NEVER invade and are not considered invasive by any standards.