Dahlia tubers are expensive and some of the more exotic varieties can take a substantial bite out of your budget. The good news is, you can get a real bang for your buck by taking dahlia stem cuttings in late winter. Taking cuttings from dahlias can net you five to 10 plants from a single tuber. Let’s learn more about growing dahlia cuttings so you can enjoy even more beautiful dahlia plants each year.
Propagating Dahlias by Taking Stem Cuttings
Want to try your hand at rooting dahlia cuttings? Just follow these simple steps.
Bring your tubers out of winter storage in late January or early February. For growing dahlia cuttings, choose the firmest, healthiest tubers.
Place the tubers in a plastic bag and put the bag, with the top open, in a warm room for a couple of weeks. Note: This step isn’t absolutely necessary, but allowing the tubers to warm in this manner will speed sprouting.
Fill a plastic planting tray to within an inch (2.5 cm.) of the top with damp potting mix or a mixture of half peat moss and half sand. For best results, use a tray with a depth of approximately 6 inches (15 cm.). Be sure the tray has several drainage holes. (If you’re only planting a few tubers, you can use plastic pots instead of a tray – one pot per tuber.)
Plant the tubers in rows about 4 to 6 inches (10-15 cm.) apart, with each stem 1 to 2 inches (2.5-5 cm.) above the surface of the soil. Write the name of each dahlia on a plastic label and insert it next to the tuber. You can also write the name directly on the tuber before planting, using a regular pencil.
Place the tubers in a warm, sunny room, but avoid direct sunlight. You can also place the tubers under fluorescent lights. Allow about 9 inches (22 cm.) between the top of the tubers and the light.
Keep the planting medium slightly moist. Watch for eyes to appear, which generally takes about seven to ten days. However, some may sprout sooner, while others may take a month or more.
When the shoots have three to four sets of leaves, they are ready to take cuttings. Use a sharp, sterile craft knife or razor blade to slice off a shoot with a narrow sliver of tuber about the width of a dime. Cut above the lowest node or joint to leave a bud on the tuber.
Place the cutting on a clean cutting board and use the sharp knife to remove the lower leaves. Leave the top two leaves intact. Dip the bottom of the cutting in liquid or powdered rooting hormone.
Place each dahlia cutting in a 3-inch (7.5 cm.) pot filled with a mixture of half potting mix and half sand. Place the pots in a warm room or on a warm propagation mat. You can also place them on top of a refrigerator or other warm appliance. Water as needed to keep the planting medium moist, but not soggy.
Watch for the cuttings to root in two to three weeks. At this point, you can allow them to develop a bit more, or you can plant them outdoors if weather permits.
New shoots will form from the remaining bud on the original parent tuber. After about a month, you can take more cuttings from the tuber. Continue taking cuttings until you have all you need, or when the cuttings are weak or too thin.