When plants or grass can be simply pulled from the ground, they are typically not recoverable and are almost certainly dead. When the roots continue to keep hold, it is an indication that the plants or grass are dormant. To rehydrate plants and grass, water them
Take a small portion of your brown grass or the plant you're concerned about and tug on it gently. If it comes out easily, then it's dead. Dead grass and plants will not regenerate, but you may take measures to replenish or regrow dead lawn and revive dehydrated and underperforming plants.
Plants can be renewed by regular watering, fertilization, and with a little extra care and attention. Add new mulch and groundcover to assist. New stems should start developing in plants after about 3-4 weeks of modest watering.
After that, when new leaves emerge and become more developed, trim stems that are no longer producing leaves. Slowly water the soil for a few minutes every day to keep it moist.