How to Divide Overgrown Hydrangeas

Hydrangeas are prized ornamental shrubs that bloom beautifully from spring through fall. Their large showy flower heads come in shades of pink blue, purple, white and green depending on the variety. However, hydrangeas grow rapidly and can become overgrown and unruly over time. Dividing oversized hydrangeas helps rejuvenate them and controls their size. Here’s a step-by-step guide to dividing overgrown hydrangeas.

When to Divide Hydrangeas

Dividing hydrangeas is best done in early spring or late fall when the plants are dormant This reduces transplant stress, The specific timing depends on your climate

• In colder zones, divide in early spring before new growth emerges.

• In warmer zones, late fall after the leaves drop is ideal.

• Avoid dividing hydrangeas during summer when they are actively growing.

Dividing every 2-3 years will help maintain a healthy, manageable size. Only divide when plants are overgrown and flowering declines.

What You’ll Need

Gather these supplies before dividing hydrangeas:

• Sharp shovel or gardening fork

• Hand pruners or loppers

• Heavy duty knife for woody roots

• Twine or rope

• Potting soil and compost

• Mulch such as wood chips or straw

• Wheelbarrow for moving divisions

Step 1: Prepare the Plant

Start by removing any dead branches and clearing the area around the hydrangea. Untangle vines or remove rocks and debris that may obstruct digging.

Prune back overlong, unsightly stems using loppers. This prepares the shrub for transplanting while removing weak wood.

Step 2: Water the Plant

Water the hydrangea thoroughly 1-2 days before dividing. This makes digging easier and prevents excessive root damage. Provide a deep soaking to moisten the entire root zone.

Step 3: Dig Around the Roots

Use a shovel to dig a trench 1-2 feet out from the drip line. Make the trench 6-12 inches deep. Slice cleanly through any thick surface roots extending into the trench.

Deepen the trench further, working around the root ball perimeter until you can lever and pry up the main shrub. Avoid excessive hacking and tearing of the roots.

Step 4: Divide the Root Ball

Lay the hydrangea on its side. Use a sharp knife to slice the root ball into segments. Aim for sections with 3-5 healthy stems each.

Divisions should have an ample portion of fibrous feeder roots. This ensures rapid establishment. Discard any divisions that lack sufficient roots.

Step 5: Transplant the Divisions

Dig holes for the divisions a bit wider and deeper than the root balls. Space holes at least 3-5 feet apart to allow future growth.

Backfill with a mix of potting soil and compost. Set the divisions in the holes at original soil depth. Firm the mix gently around the roots.

Step 6: Water Thoroughly

Water each division thoroughly after planting to remove air pockets and soak the roots. Provide additional watering every few days until plants are re-established.

Step 7: Apply Mulch

Spread 2-3 inches of organic mulch around the transplants. Mulching conserves moisture and suppresses weeds. Renew the mulch layer annually.

Step 8: Stake Tall Stems

Stake any excessively tall or floppy stems for support while the hydrangea establishes. Use soft plant ties to avoid damage. Remove stakes after several months once stems strengthen.

Aftercare Tips

• Inspect divisions regularly and water when the top few inches of soil become dry.

• Wait to fertilize until after new growth emerges in spring. Use a balanced organic fertilizer.

• Remove faded flowers to encourage additional blooming. Don’t prune otherwise the first season after dividing.

• Watch for signs of transplant shock like wilting. It normally subsides within 1-2 weeks as roots recover.

Benefits of Dividing Overgrown Hydrangeas

Dividing oversized, neglected hydrangeas offers many benefits:

• Restores vigor and improves flowering

• Prevents crowding and competition between stems

• Promotes soil aeration and root nutrition

• Multiplies your hydrangea collection

• Controls size without frequent pruning

• Rejuvenates old, overgrown shrubs

• Allows moving hydrangeas to better locations

Dividing overgrown hydrangeas requires patience and care. But the end result is beautiful, healthy shrubs with prolific blooms to enjoy. With the right technique and aftercare, your divided hydrangeas will quickly settle in and flourish.