Why to Deadhead Marigolds

Deadheading, or cutting off spent flowers, not only encourages many flowering plants to continue blooming but also keeps them looking tidy. Marigold flowers left on the plant become mushy and unattractive, especially after rainfall. Leaving them in place can detract from the newer, vibrant flowers on the plant.

Most marigolds typically grown in gardens are annuals, although there are a few perennial species. Annual flowers only have one growing season to reproduce, so there is no holding back energy to make it through the winter. They spend it all. Each marigold will produce flowers, and once they are pollinated, will focus all its energy to form seeds. Every seed is a significant investment of energy by the plant.

Deadheading interrupts that process. By removing the flower and the soon-to-be-formed seed head beneath it, the plant redirect its energy into producing more flowers.

Marigolds produce abundant seed and, if not deadheaded in the garden, will often reseed in warm climates, coming back as volunteer plants.

When and How to Deadhead Marigolds

Deadheading marigolds begins as soon as you see old, fading, droopy, or browning flowers. Marigolds purchased from a garden center are often already in bloom, so deadheading might begin shortly after you bring them home.

Continue deadheading throughout the summer and fall, until either the autumn frosts kill the plant or it dies back naturally. Frequent deadheading will make the process a quick task instead of an endless chore. Twice a week is usually sufficient to keep up.

To deadhead marigold blossoms, nip or pinch off the flower stem down to the next leaf node. Old petals tend to pull off easily, leaving the forming seed head in place. Cutting or pinching below that accomplishes the seed head removal and eliminates stubby stems sticking up from the foliage.

When deadheading, avoid removing the new buds. They can look a bit similar to forming seed heads, but will typically be a light green instead of darker green and purple, and still be tightly formed. Check for petals beginning to peek out, a fresh green appearance, and an upright aspect.

If you'd like to avoid staining your fingernails and smelling like marigolds after deadheading, wear gardening gloves and use flower snips to accomplish the task.

Deadheading Different Types of Marigolds

While the deadheading process is the same for all marigolds, here are a few species-specific pointers.

African marigolds

The stems on these large, almost bush-sized plants are too thick to pinch off with your fingernail. Use flower snips, scissors, pruning shears, or a sharp knife instead. The blooms on African marigolds are large, and they'll often droop and begin to brown or look soggy as soon as they've finished. When that happens, quickly remove them to avoid the heavy spent flower head bending the entire stem downward.

French marigolds

French marigolds are the most common at the garden center, and are typically 6 to 15 inches tall. The flower stems on these plants are soft, and easily nipped off between your fingernails.

Signet marigolds

These smallest marigolds have single or semi-double blooms and delicate, lacy foliage. Signet marigolds can be deadheaded easily with your fingers, but take care to avoid damaging the stems. If you've already removed a few blooms to use as an edible garnish, be sure to remove the immature seed pods as well.

Saving Marigold Seeds

If you are deadheading immediately after the blooms fade, the seeds will not be mature, so will not sprout when planted. Flowers that have faded for a week or two may have some viable seeds, so planting those deadheads may result in new plants. To save marigold seeds to grow next year, you'll need to let some of the flowers remain long enough to fully mature.

Marigold flowers and seed heads form rather quickly, so you can keep deadheading until late summer or even early autumn. Marigolds need about six weeks from the time a flower opens until the seed is mature and ready for storage. In areas where frost will kill the plants, count backward six to seven weeks from your average first frost date and stop deadheading a few plants then. 

To judge seed maturity, pull apart the dried flower head and look at the seed color. Mature marigold seeds will be dark brown or black, not white or yellowish. Remember, seed saved from hybrid marigold varieties will likely not replicate true to the parent plant and may be sterile.