Italian Arum (Arum italicum) is a perennial plant that is both strikingly attractive and aggressively invasive, making it a difficult weed to manage once established. Initially prized for its elegant, marbled foliage, this species has become a common garden escapee, spreading rapidly to displace native vegetation and form dense monocultures. Its unique growth cycle and subterranean biology allow it to persist despite control efforts, requiring a specialized, multi-year eradication strategy.
Identifying Italian Arum and Understanding Its Persistence
Correctly identifying Italian Arum is the first step in successful eradication, as its appearance changes throughout the year. Its most recognizable feature is the glossy, arrowhead-shaped leaves, often mottled with pale green or cream veins, which emerge in late fall and persist through winter and early spring. In late spring, the plant produces an unusual flower—a pale green, hood-like spathe—followed by a spike of tightly clustered, bright orange-red berries in the summer. All parts of the plant are highly toxic and contain irritating calcium oxalate crystals, so protective gloves must be worn when handling the plant.
The plant’s persistence is rooted in its specialized biology, allowing it to evade simple removal methods. Below the soil, Italian Arum grows from a deep, tuberous corm, which serves as a large energy storage organ. This central corm produces numerous small offsets, or cormlets, that easily break off during digging and can quickly sprout into new plants. The prolific berries contain seeds readily dispersed by birds, ensuring the infestation spreads rapidly.
Manual and Cultural Removal Techniques
Manual removal is the most effective method for small, isolated infestations but demands meticulous attention to detail. This technique requires digging out individual plants when the soil is moist, typically in late fall or early spring when the leaves are fully present. The goal is to remove the entire central corm and all attached or detached cormlets, which may be located deep in the soil.
Carefully sifting the excavated soil is necessary to ensure no cormlets are left behind, as even a small fragment can regenerate a new plant. Any removed soil should be treated as contaminated and disposed of properly, not reused in other garden areas. This method is labor-intensive and must be repeated over several years to catch sprouts from missed cormlets or new seedlings.
For larger, dense patches, cultural techniques like solarization or smothering offer a practical non-chemical approach. Covering the infested area with a thick, opaque material, such as black plastic sheeting or heavy landscape fabric, starves the plants of light and air. This process must be maintained for 12 to 18 months to fully deplete the energy reserves stored in the corms.
Cutting or mowing the foliage is insufficient for long-term control because the corms store significant energy, allowing quick regrowth. However, repeated cutting of all new foliage as soon as it appears can be used as a long-term strategy to weaken the corms over multiple seasons. This approach prevents the leaves from photosynthesizing and replenishing underground energy reserves.
Effective Chemical Control Strategies
Chemical control is often necessary for large or widely established infestations. Contact herbicides are ineffective because they only kill the tissue they touch and do not reach the underground corms. The best approach involves using a systemic herbicide, such as a product containing glyphosate or triclopyr, which is absorbed by the leaves and transported down to the root system.
Timing the application is important to maximize effectiveness, as it must coincide with the plant actively moving sugars to its corms. The most successful period for application is late fall or early winter, after the leaves have fully emerged but before the plant enters summer dormancy. Herbicide applied during dormancy or flowering will not be adequately translocated to the corm.
Application should focus on spot treatments to minimize damage to surrounding desirable plants, applying the product directly to the foliage according to label instructions. A single application is rarely effective for complete eradication due to the plant’s robust root system. Multiple treatments over two to three years are required to achieve satisfactory control, with follow-up applications targeting any regrowth.
Disposal and Long-Term Site Management
Proper disposal of removed plant material is necessary to prevent re-infestation and the spread of Italian Arum elsewhere. The plant’s corms, cormlets, and seeds are highly resilient and can survive and sprout in traditional composting environments. Therefore, all plant parts—including foliage, corms, and especially the bright orange-red berry clusters—must be sealed in sturdy plastic bags.
These bagged materials should be disposed of in the regular trash stream, directed to a sanitary landfill, rather than being placed in yard waste bins or home compost piles. All berry clusters must be clipped and bagged before they ripen to prevent seed dispersal.
Long-term management requires persistent monitoring of the cleared area for several years. Any new sprouts emerging from missed cormlets or germinating seeds must be immediately removed before they establish an energy reserve or produce berries. A successful strategy includes immediately replanting the area with a dense cover of desirable, non-invasive groundcover or turf. This competitive planting helps suppress any Italian Arum seedlings that attempt to germinate.