Ground Ivy

The Plant Most People Think They Know

English Ivy (Hedera helix) and Algerian Ivy (Hedera algeriensis) are among the most pervasive invasive plants in the San Lorenzo Valley. They differ in leaf size – Algerian Ivy is the larger of the two, with broader, glossier leaves – but their ecological impact is the same, though the approach to their removal differs somewhat. What most residents recognize as a familiar, even unremarkable ground cover is, in practice, among the most ecologically destructive forces now moving through the forests, creek margins, and riparian corridors of the Santa Cruz Mountains.

Both species originate from the Mediterranean region, including parts of Europe, North Africa, and the Canary Islands. They arrived here as ornamentals – planted for erosion control along roadsides, used as ground cover beneath trees where little else would grow, valued for the appearance of green where gardeners wanted it without effort. Their reputation for toughness and for providing year-round greenery with little effort is precisely what makes them dangerous.

Ivy does not stay where it is planted. It moves – steadily, year after year – into forest edges, shaded understories, and the moist corridors along seasonal swales, creeks such as Bear Creek and Zayante Creek, and the San Lorenzo River. Habitats that are among the most ecologically valuable and most difficult to restore in this valley.

How the Juvenile Phase Spreads

Ivy on the ground is the plant’s juvenile phase. In this stage, it does not flower or produce berries. Instead, it spreads outward through vegetative growth.

It spreads through long trailing stems, often called cords, that extend outward across the ground, forming dense mats.

The juvenile phase can persist for many years before a climbing stem reaches a vertical surface and enough sunlight to trigger the transition to the adult, berry-producing form.

In the meantime, the ground mat spreads in every direction from its point of origin — across slopes, through understory plant communities, along creek banks, and across disturbed ground.

Disturbance accelerates this expansion. In the San Lorenzo Valley, where storms, mudslides, fire, or human activity periodically open the ground, ivy is often the first plant to claim the space.

Where the Ecological Damage Begins

The damage begins long before ivy reaches the trees.

As the mat thickens, it begins to change the forest floor itself. Ivy leaves form a dense evergreen layer that blocks light from reaching the soil. Native seedlings that would normally germinate in small openings of sunlight struggle to emerge.

Native plants, ferns, wildflowers, and young shrubs gradually disappear beneath the expanding vine layer.

The mat also replaces the natural leaf litter that normally accumulates beneath trees. In healthy forests, fallen leaves and needles form a loose layer of organic material that supports small soil organisms, fungi, and insects that build soil and cycle nutrients. When ivy covers the ground, the health of this living layer is reduced or lost.

Over time, the structure of the understory changes. Instead of a diverse community of native plants, ferns, shrubs, and leaf litter, the ground becomes dominated by a single vine layer. The loss of this layered complexity reduces habitat for insects, amphibians, ground-foraging birds, and other small animals that depend on the forest floor.

For this reason, the ground phase of ivy is both the beginning of the problem and the place where intervention and removal are most effective.

Controlling ivy while it is still on the ground prevents the plant from reaching the canopy, producing seed, and spreading deeper into forests and riparian corridors through birds.

Here is how to begin.

Removing Ground Ivy: A Practical Approach

Ivy removal does not need to happen all at once. It needs to happen consistently. Each cleared patch extends the margin a little further, and progress becomes visible surprisingly quickly.

1. Find the natives first

Before you begin, locate where your native plants are growing. Protect what remains first.

Native plants and shrubs may still be present within the ivy mats and around the outer edges of the ivy — suppressed, reduced in vigor, but alive. Flag them before any cutting begins.

These plants should be gently freed from the ivy, and the ivy pulled back beyond their root and drip lines.

As they regain health, they will begin spreading naturally into the areas you have cleared, gradually reclaiming the cleared ground.

2. Start at the edges

You may be inclined to begin where mats are densest, but begin at the edges where native plants may still be holding ground — and where recovery will happen more quickly.

3. Time your work with the season

Removal is most effective after the first rains have moistened the soil, making the long trailing stems — called cords — and their shallow roots easier to loosen and lift.

During the dry months, outward spread can be slowed by cutting cords back to where they are rooted, preventing new rooting points from forming.

4. Work in manageable sections

A pitchfork and pruners are your most useful tools.

Use the pruners to cut the cords back to where they are anchored in the soil. Then use the pitchfork to loosen the soil around the root and lift it out.

Ivy grows in mats of interconnected cords both on the surface and just beneath the soil. When a cord snaps, the break usually occurs at a weak point — the root mass remains in the ground. Cords need to be traced back to their roots and lifted there, not simply pulled until they break.

These matted cords often need to be cut into smaller sections and untangled. Along the cords, there will be sections where roots have formed, and these must be lifted out as well.

As you work, move backward across the area — stepping on the existing ivy mat rather than the newly cleared soil. Freshly exposed ground is vulnerable to compaction, and keeping your weight off protects both the soil structure and the organisms beginning to recover beneath the surface.

5. Remove the material

Do not leave piles of ivy on site.

Use a tarp to collect cut material as you work, then haul it to the green waste.

Ivy will resprout from root fragments left in the soil and on the surface.

Even ivy that does not re-root can continue to affect soil chemistry as it breaks down, suppressing the recovery you are working toward.

6. Protect the cleared ground

As you work through the mat, you will encounter woody debris — branches, limbs, and bark.

Place it back onto previously cleared ground so it remains in contact with the soil.

Scatter any available duff you have access to; otherwise, leave the soil undisturbed.

Do not add wood chips. Chips can suppress the native seedlings already present in the soil, waiting beneath the ivy for light and space to return.

7. Return to monitor

Monitor restored areas as you return to continue eradication.

During the dry season, watch for resprouting and flag it for removal after the first rains. If the soil is soft enough, it can be removed immediately.

Return to cleared areas to remove resprouts before they reestablish.

Each monitoring visit is shorter and easier than the previous one.

Closing

Each cleared patch is an opening. You are tending a process that is already moving in the right direction.

Revegetation does not happen immediately – it can take a season, sometimes more. But the removal begins the restoration process.

Small sessions. Consistent attention. The edges first. The rest follows.