While, broadly speaking, nature is a dominant theme in Romantic poetry, it is more important to examine what these poets are saying about nature and how they use it. Romantic philosophy was a response to the Enlightenment and Rationalism and the scientific and technological advances it brought. Romantics believed that logic and reason could no longer solve life's problems and, in fact, were creating more. As such, Romantics sought to restore man's relationship with nature. They saw nature as something pure and uncorrupted and, therefore, almost spiritual. Most Romantics believed that humans were born pure and good and that society corrupted. Nature, therefore, became a symbol of life without society, a truly good life. Nature becomes a place where one can go to reflect and comtemplate the many questions of life, a place where one can find solace and happiness in its purity. While most Romantic poets do write about nature, some also write about life in the city. However, these poems tend to be much more dark and emphasize the idea that society corrupts.
For an illustration of these ideas consider Wordsworth's "The World Is Too Much With Us in It." Throughout this poem he seems to be chastising mankind for losing their connection with nature and becoming much more caught-up in things like consumerism. He ultimately rejects such a society in favor of a much more simple past culture (Ancient Greece), where nature is appreciated and celebrated. Also consider Keats's "When I Have Fears that I May Cease to Be." Throughout this poem Keats lists the various worldy fears he has, using references and comparisons to nature, ultimately to state that when he experiences such anxiety all he must do is go out into nature and think until all of these fears "to nothingness do sink."
Examples like these are abundant in Romantic writing, and I would encourage you to examine the poems you are studying to find examples that connect to these ideas.
For the Romantics, nature was a fairly dominant theme and occupied a very prominent role in the poetry. For these thinkers, nature helped to enhance the individual experience. The exploration of self takes place perfectly when embedded in the natural setting. There is a powerful and potent element to the natural setting in its reverence. The pantheistic view helps to enshrine the role of nature in the Romantic poet. At the same time, the love of nature was almost a response to what the prevailing social order espoused at the time. Neoclassical society was cosmopolitan and conformed life took place in the urban setting. For the Romantic thinker, to break from this into a new realm was liberating and powerful. This is where the love of nature took on both the form of a statement and response.
Ya, Nature was one of the central themes in the discourses of Romanticism. The English Romanticists owed a great deal in this respect to Rousseau's theory of 'noble savage', and his fictional work, New Heloise'. Romanticism, in its urge to break away from the 18th century tradition strongly founded on rationalism and scientism, shouted a slogan of going back to Nature.
Among the pioneers of the Romantic Revival in English poetry, it was Wordsworth who wrote profusely on the subject of Nature. His simple Lucy Poems, more philosophical Tintern Abbey, and largely autobiographical, The Prelde were examples of his poetic naturalism. Coleridge was more inclined to supernaturalise Nature, and his dream-poem, Kubla Khan was a case in point. His Dejection:An Ode examined the Man-Nature relationship in a critical angle. Shelley adopted such elements of Nature as the sky, the clouds & the winds as vehicles of his neo-Platonic philosophy. Keats was primarily a poet of great sensations to explore Nature in his immortal Odes.