No, the roots of your desirable plants are meant to grow safely under the fabric, while the fabric itself is engineered to stop weed roots from growing through. High-quality landscape fabric is designed to be a tough, physical barrier that blocks weed seeds from the soil below from pushing up and, just as importantly, prevents airborne weed seeds that sprout in the mulch from sending their roots down into the soil.
Because the fabric is permeable, the roots of your shrubs and trees can thrive in the soil beneath it, easily accessing the water and air they need, they're not encouraged to push upwards toward the barrier. While an extremely aggressive, established weed might try to push through, a strong, professional-grade fabric is your best defense to ensure only your intended plants flourish.
