Keep Your Dahlias Blooming All Summer with This One Simple Trick

Whether you’re growing dahlias in containers or planted a large patch of them in your garden, their gorgeous, stop-in-your-tracks blooms are sure to delight. To get as many dahlias as possible and keep the plants flowering for longer, there’s one little trick to know: Deadheading. Keep up the flower power all summer long with these tips on how and when to deadhead dahlias properly.

Benefits of Deadheading Dahlias

Like other flowering plants, a dahlia produces flowers as part of its reproductive cycle. After the flowers fade and the petals fall off, the plant naturally starts focusing energy on seed production. Removing the flower before seeds develop redirects the plant’s energy to making more flowers instead.

Unless you’re gathering and saving seeds to plant next year (which is not recommended for hybrids because you won’t get plants true to the parent), there’s no need to let your dahlias produce seeds. The plant will still produce tubers that can be dug and divided, yielding daughter plants for next year, which are identical to the parent.

Deadheading dahlias also keeps your plant looking tidier. A fading dahlia often turns brown, droops, and looks a bit bedraggled, and finally loses its petals.

When to Deadhead Dahlias

Whether you have one dahlia or a few dozen, the time to begin deadheading is based on the variety and maturity of the plant. Not all dahlias bloom at the same rate after planting; some may begin blooming as early as 75 days after planting, while others may take more than three months. Bedding dahlias may already be in bloom when purchased from the garden center, so you’ll need to be deadheading much sooner.

Deadhead dahlias when an individual bloom is fading and no longer attractive. There is no need to wait longer until the petals fall or the flower starts to look brown and unappealing. Typically, a once-per-week deadheading is sufficient to keep your dahlia cranking out more blooms all season long.

Once you start deadheading, continue the routine until your first frost kills the above-ground portions of the plant.

Steps for Deadheading Dahlias

Like other flowers, deadheading dahlias is quite simple. You’ll need sharp garden shears or snips.

1. Select a faded flower and follow the stem down, cutting it 12 inches or more below the bloom, deep into the plant to encourage more long stems. Prune bedding or dwarf dahlias like other potted plants, cutting just below a leaf node or two to hide it from view.
2. Sterilize your pruning tool between plants. Dahlias are susceptible to bacterial, viral, and fungal diseases, and those can be transferred from an infected plant to a healthy one. A 10% bleach solution will work (one cup of bleach to 9 cups of water), as will wiping the blades with 70% rubbing alcohol.
3. Collect the deadheaded dahlia flowers and toss them in your compost bin (or yard waste bin if they are from a diseased plant).