Yes, plants can certainly survive without humans because most of the plants rely on the natural resources and the nature, rather than on the man. For instance, in the rainforests, there are no men to continuously water the plants and to look after them.
Yet, the plants still happen to survive as they take their water from the rainfall, and energy from the sunlight. This rules out the need of humankind for plants to survive. It would be correct to say that plants are completely independent of other species for survival and are solely dependent on the natural resources. Though, many plants do rely on insects for propogation of pollen.