The appearance of grass and weeds pushing through the seams and cracks of a driveway is a common frustration for property owners. Beyond the immediate aesthetic concern, these plants actively contribute to the structural degradation of the paving material. As the roots expand, they exert pressure on the surrounding asphalt or concrete, widening existing fissures and allowing more moisture to penetrate beneath the surface. Addressing this problem requires a two-part strategy: effectively killing the current growth and then implementing measures for long-term prevention.
Non-Toxic and Natural Removal Methods
For those who wish to avoid commercial chemical herbicides, several natural methods use readily available materials to achieve localized grass and weed control. Pouring boiling water directly onto the unwanted growth is one of the quickest methods to damage the plant tissue. The extreme heat instantly ruptures the plant’s cell walls, acting as a contact killer that causes the foliage to wilt rapidly. This technique is most effective when directed at the crown of the plant, but it is less reliable against deep taproots, which may allow the plant to regrow.
A more potent natural option involves using high-acidity vinegar solutions, which are significantly stronger than standard 5% kitchen vinegar. Horticultural-grade vinegar, often containing 20% acetic acid, functions as a non-selective, contact herbicide by desiccating the plant on contact. For maximum effectiveness, the solution should be applied on a hot, sunny, and dry day, as the heat enhances the vinegar’s ability to burn the plant tissue. While adding salt to a vinegar solution is sometimes suggested, this practice should be used sparingly, as salt can contaminate surrounding soil and may contribute to the breakdown of concrete over time.
Manual removal with specialized crack-weeding tools or a stiff wire brush can provide immediate results. These tools scrape out the visible growth and the accumulated soil and debris that supports it. However, this method is often temporary; if even a small portion of the root system remains embedded, the plant will likely sprout again. Complete physical extraction of the root is necessary to prevent re-emergence, which is challenging in narrow, deep crevices.
Targeted Chemical Solutions
When seeking a faster, more permanent solution for deeply rooted perennial grasses and weeds, targeted chemical herbicides provide a systemic approach. Systemic herbicides, such as those containing glyphosate, are absorbed through the leaves and translocated throughout the entire vascular system of the plant, including the roots. This process ensures the destruction of the entire plant structure, preventing regrowth from the root system.
It is important to differentiate between systemic killers and contact killers, which only destroy the green tissue they touch, often leading to rapid regrowth from intact roots. Herbicides are categorized as non-selective (killing any plant they contact) or selective (targeting only certain weed types). Since the goal is to kill all growth in the driveway cracks, a non-selective, systemic post-emergent product is typically chosen, applied only to the target weeds.
A different class of chemical, the pre-emergent herbicide, works by creating a chemical barrier that prevents weed seeds from germinating. These products prevent new grass and weeds from sprouting but are ineffective against existing, actively growing plants. When using any chemical solution, reading the product label is paramount, specifically for instructions on personal protective equipment (PPE), such as gloves and eye protection. Application should occur during calm, dry weather to maximize absorption and minimize the risk of chemical runoff.
Sealing Cracks for Permanent Prevention
Killing the existing growth is only the first step; achieving a permanently grass-free driveway requires eliminating the environment that allows seeds to germinate. Once the grass and weeds are completely dead, the cracks must be thoroughly cleaned of all debris, soil, and dead plant material. A high-pressure washer or a wire brush can be used to excavate the crevices, ensuring the crack walls are clean and dry.
The long-term solution involves sealing the cracks with a flexible material to block the entry of seeds, soil, and moisture. Unlike rigid materials like concrete patch or mortar, which crack as the pavement expands and contracts, flexible sealants are designed to move with the driveway. Polyurethane or silicone-based self-leveling sealants are recommended for horizontal cracks, as they adhere well and maintain flexibility across temperature changes.
Regular inspection allows for the prompt re-sealing of any new fissures that appear. By effectively removing the existing plants and then sealing the cracks with a durable, flexible sealant, the necessary conditions for future grass and weed growth—soil, light, and moisture—are eliminated. This proactive maintenance ensures the driveway remains structurally sound and vegetation-free.