Help Centre

🪴 What to Do When Dahlia Cuttings Don't Tuber Up

It's common for dahlia plants grown from cuttings (or from seed) to produce beautiful blooms all season but fail to develop a large, solid tuber clump in their first year. This happens because the plant prioritized flowering and building a dense root system over storing starch in large tubers.

If you dig up your plant and find only a fibrous root ball with a few thickened pieces, here is what you can do to save the genetics and ensure you have tubers next year:

1. Identify and Save the Crown

The most important part to save is the crown. The crown is the small, hard section of the plant where the stem meets the roots. This area contains the dormant buds (eyes) that will sprout next spring.

  • Locate the Crown: The crown is a solid, knobby piece of tissue just at or slightly below the soil line, directly at the base of the stem.
  • The Goal: Even if the plant didn't form large tubers, the crown itself can often be saved and is the key to overwintering the plant.

2. Save the Fibrous Roots

Do not discard the entire root ball! The dense, fibrous roots, while not technically tubers, have stored energy and can help support the crown through the winter.

  • Trimming: Trim the fibrous roots back so they are manageable, but do not wash them vigorously as you might with a firm tuber clump. You want to leave some soil clinging to them, which provides insulation and protects the crown.
  • Keep the Connection: Ensure the roots remain firmly attached to the central crown piece and the base of the stalk.

3. How to Store the Crown and Roots

You will save the crown and attached roots using the same principles as mature tubers, but they require extra care to prevent desiccation (drying out) due to their small size and lack of a thick skin.

  1. Curing (Optional but Recommended): Let the crown and roots air dry indoors for 1-3 days in a cool, protected space to allow the surface to heal slightly.
  2. Packing: Place the entire crown/root ball system into a small container (like a plastic bag, small box, or pot).
  3. Use a Medium: Surround the crown and roots with a slightly insulating, slightly damp medium. Options include vermiculite, peat moss, or wood shavings. The medium should be barely moist—not wet—to prevent rot.
  4. Storage: Store the packaged roots in a cool, dark location where the temperature remains stable, ideally between 40°F and 50°F (4°C and 10°C). A cellar, unheated closet against an interior wall, or a cool garage works well.

4. The Second-Year Payoff

Next spring, when you plant this saved crown and root system, the plant will already be established. It will dedicate its energy to much stronger root development, almost certainly producing a large, healthy, and harvestable clump of tubers by the end of its second growing season.

In summary: Yes, the roots (and especially the crown) can and should be saved! Handle them gently, keep them slightly damp during dormancy, and you'll be rewarded with a productive tuber clump next year.