The ficus (Ficus spp.) can be a difficult tree to control or kill. Long after being cut down, seedlings can keep popping up around the former root system and try to retake the tree's former territory. Their fight for life will continue as long as the roots have activity in them. You have several choices of chemical treatments to finally end the battle. Which to use depends on your comfort level with chemical strength and residual soil effects. Ficus is a large family, with varieties hardy growing throughout U.S. Department of Agriculture plant hardiness zones 6 through 11.
The Ficus Strangler
The ficus, or fig (Ficus carica), is commonly found in USDA zones 6 to 11. Invasive and opportunistic, the ficus can grow in many inconvenient locations such as through cracks in walls or small holes in drainage systems. They often overtake an entire host tree, eventually strangling the life from it. Killing a ficus is not an easy task, as they are also very quick to recover and can regrow from stumps or bits of roots that are still alive. To kill one fully, you must kill the entire root system, which usually involves chemical means.
Triclopyr Amine, Meet Triclopyr Ester
One of the most effective ways to kill ficus roots is by drilling holes into the roots and injecting the growth inhibitor triclopyr. Two types are available on the market, amine and ester. Inject fully concentrated triclopyr amine into the roots late into the growing season. This broadleaf-selective herbicide has very low soil residuals, so has less chance of damaging future plants. Triclopyr ester works in a similar manner to amine, but is more potent and has a high soil residual, making it dangerous to other plants in the future. It has the ability to vaporize in relatively low temperatures, so should not be used when outdoor temperature is above 85 F.
Two other options for chemical treatment are glyphosate and imazapyr. Glyphosate is an aromatic amino acid inhibitor that has little soil reactivity, meaning it is not easily absorbed into the roots and must be injected into holes drilled in the roots to be effective, just as with tryiclopyr. Imazapyr, on the other hand, is extremely active in soil and its effects can last well past a year. If you plan on using the soil for a future project, it is best to avoid this particular chemical.
For the least harsh chemical effect on your soil, use copper sulfate crystals to kill ficus roots. Like other chemicals, the best practice is to excavate some large roots and drill thick holes in them. Pour copper sulfate crystals into the holes and water them well. For the resilient ficus, you may have to perform this more than once on various areas of the root system.
- California Rare Fruit Growers: Fig Fruit Facts
- University of California Davis: The Weed Report: Ficus Carica L.
- University of Florida IFAS Extension: Herbicides to Kill Invasive Trees in Home Landscapes
- Arizona State University: Ficus Carica
- University of Florida IFAS Extention: Ficus Benjamina: Weeping Fig
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