Zinnias have brown lower leaves, near the base of the stem.

Question

I bought some Zinnias from a nursery 3 days ago and the bottom leaves have stayed brown. Should I cut them off? I can tell the plants are healthy as a bud of a zinnia blossomed into a very pretty red flower and all the upper leaves are gorgeous, while the bottom are icky. This has occurred in all of my 6 zinnia plants. I have avoided watering the bottom leaves as much as possible as well.
Remove or let them be?

Answer 1

The plant looks healthy overall. Bottom leaves that get shaded as the plant grows often turn yellow, then brown. They are “senescing”, a nice term for getting old. Once a green leaf has turned yellow, it is no longer capable of photosynthesis. I remove them for aesthetic reasons. Fighting off diseases and bugs is an on-going battle for commercial growers. Removing off-colored foliage reduces the chance of infecting more leaves. Keep annuals healthy by watering regularly and giving them fertilizer. Don’t crowd zinnias; they need good air circulation since they are prone to powdery mildew in hot, dry weather.