Clematis do not need a lot of space. They associate well with other plants. Low-growing early-flowering perennials, such as creeping phloxes or rock cress, make perfect companion plants for clematis. They are already in flower, when clematis breaks into growth in spring. In summer they make a green carpeting ground cover around clematis, which helps to preserve moisture. Pergolas and trellises, planted with clematis, mask dying foliage of tulips and daffodils well, while looking unobtrusive during April and May, when these bulbs are in flower. Exuberant growth of clematis soon hides their unsightly dying leaves.
If you have a vast lawn, you should try pairing clematis with tall sturdy perennials, but vigorous deep-rooted plants are best avoided. Feeding roots of these plants and clematis will mingle to an extent, where transplanting will be impossible without damaging the roots.