How to Use Rooting Hormone to Successfully Propagate Your Plants

If you want beautiful, full, diverse planters without the hefty price tag, you may consider propagating your plants—growing new plants from clippings of existing plants.

While it's a fairly simple process requiring little more than soil and sunlight, you can give Mother Nature a boost by incorporating rooting hormone into your process. Our experts offer tips on when and how to use rooting hormone while propagating plants.

What Is Rooting Hormone?

Just as hormones regulate processes in the human body, plants have hormones—chemicals known as auxins—that help govern their growth and development by triggering root formation. Rooting hormone products, which are commonly sold in powder, liquid, and gel form, contain natural auxins or synthetic compounds, which can be applied to clippings to stimulate root growth during propagation.

When to Use Rooting Hormone

Many plants propagate naturally, and if given the proper conditions and care, cuttings will sprout roots using their own hormones. However, some people choose to use rooting hormones to speed up the process or for plants that have proven difficult to propagate in the past. "It's a personal choice," says Nadine Kremblas, conservatory horticulturist at Marie Selby Botanical Gardens. "Rooting hormone can help yield better results, but it's not necessary."

Plants that easily propagate, such as most varieties of succulents, rarely need the jumpstart that a rooting hormone can deliver. However, plants that are more reluctant to root, such as citrus plants, can benefit from it.

If you choose to incorporate rooting hormone into the growing process, remember that it should only be used during propagation. Feeding a mature plant hormones can damage the root system.

Cuttings That Benefit From Rooting Hormone

While rooting hormone can help nearly any type of plant, some varieties see more benefits than others.

"Many common houseplants and ornamentals can root without it, but rooting hormone can speed things up and increase success rates. Plants that root very easily—like herbs, coleus, pothos, and spider plants—might not see a significant difference with rooting hormone," says Andrew Bunting, vice president of horticulture at the Pennsylvania Horticultural Society. "Woody ornamental plants can see a big boost from rooting hormone."

Bunting suggests using rooting hormone for the following plants:

• Roses
• Hydrangeas
• Viburnums
• Lilacs
• African violets (slow rooters)
• Jade plant leaves (and other succulents that struggle to root)

However, the correct application of rooting hormone won't hurt a plant, so new gardeners may want to add it to their product lineup to be on the safe side. "Ultimately, it depends on the specific plant and your experience level," says Bunting. "If you're unsure or a beginner, rooting hormone can be a helpful insurance policy for those trickier cuttings."

Choosing the Right Type of Rooting Hormone

Rooting hormone comes in three versions: powdered, liquid, and gel. Each has its strengths. Choose the one that is best for your experience level and the type of plant.

• Powdered: This version is easy to apply and good for beginners, says Bunting, although it can create more dust or mess than other forms. "[It] works well for stem cuttings with a thick stem base, as they can easily absorb the powder," he says. Check the potency levels—different powders have varied levels of active ingredients.
• Liquid: Liquid rooting hormone can be precisely applied and works well for small cuttings or delicate plants up to shrubs and trees, says Bunting. It can also be diluted to adjust the strength. "[Using liquid] requires dipping the cutting, which might introduce unwanted pathogens if not done carefully," says Bunting.
• Gel: Gel sticks well to moist cuttings, says Bunting, so although it's a little more costly, it's good for root cuttings that are thin, small, or have awkward angles, and it won't be messy.

How to Use Rooting Hormone on Stem, Leaf, or Root Cuttings

Rooting hormone can be applied to stem, root, and leaf cuttings. Follow these instructions to take cuttings, apply rooting hormone, and replant each type of cutting.

Stem Cuttings

"Pick a healthy stem that's not flowering, and cut it diagonally just below a leaf node with a sharp knife or pruners (cuttings should be 3 to 5 inches long)," says Bunting. Here are Bunting's steps for using rooting hormone with stem cuttings:

1. Remove the lower leaves and cut the remaining leaves in half. 
2. Moisten the bottom of the stems and dip them in rooting hormone.
3. Plant the cutting in moist potting mix.
4. Keep it warm and humid until you see new roots.

Leaf Cuttings

Since not all plants propagate via leaf cuttings, confirm your plant's method before cutting. Bunting suggests the following steps for using rooting hormone with leaf cuttings:

1. "If your plant can propagate via leaf cutting, choose a healthy, mature leaf," says Bunting.
2. "Cut it off at the base with a sterile knife or pruners," says Bunting. "If your leaf has a stem, remove some of it."
3. Dip the cut end in rooting hormone and plant it shallowly in moist potting mix.
4. Keep it warm and humid until new growth appears. 

Root Cuttings

This type of cutting is the least common, says Bunting, and likely won't require any extra help from rooting hormone. If you choose to use it, follow these steps:

1. Carefully unearth a healthy root about pencil-thick, says Bunting.
2. Cut a 2- to 3-inch section with a sterile knife.
3. Replant the section horizontally in moist potting mix, burying it about an inch deep.
4. Keep it warm and humid until new growth sprouts.

Tips for Applying Rooting Hormone

Bunting suggests being mindful of how much rooting hormone you're using. He suggests using the following tips when working with the substance:

• When applying rooting hormone to a cutting, avoid putting the cut end directly into the package with the rooting hormone. Instead, pour some hormone into a smaller container and dip the cutting into that to avoid spreading disease.
• Dip cut ends into powder or liquid rooting hormone only briefly. Tap off excess powder or droplets. "Less is more with rooting hormone," says Bunting.
• "For all cutting types—stem, leaf, or root—you only need a thin layer," says Bunting. "Aim for a light coating, not a heavy drench."
• "Never pour the extra back into the original container," says Bunting.