Clematis is a flowering vine distantly related to the buttercup. The name of the plant is a derivative of a Greek word that means vine. Clematis prefer to have full sun on their branches, but need cool soil for their roots to grow in. To supply this, gardeners often plant shrubs or other low-growing plants around the base of clematis to shade the roots and soil.
Plants that are placed beneath clematis should have shallow, non-invasive roots so they do not crowd out the roots of the vine. This is important since clematis can take a year or more to establish and will have slow root development during this time. Good plants to place around the root zone of clematis include hardy geraniums, artemisia, creeping phlox, candytuft, coralbells and veronicas. These plants may be surrounded with a 2-inch layer of mulch, which will also cool the soil around clematis roots.
Low-growing shrubs that are planted outside of the root zone of clematis will shade the roots of the vine without crowding the plant. Shrubs such as dwarf boxwood, yew or Japanese holly are evergreens that will provide year-round colour. Dwarf hollies also provide red berries in winter for seasonal interest. Other shrubs that may be planted with clematis include glossy abelia, dwarf aucuba, red Japanese barberry, flowering quince, cotoneaster, gardenia and St. John's Wort.
Plants that require the same types of fertiliser and the same amount of water are good companion plants for clematis. Low-growing shrub roses such as Knock Out roses are plants with similar cultural requirements. Roses such as this should be planted approximately 6 inches from clematis to avoid crowding the vines. Give clematis a trellis to climb and trained the vine to the trellis so that it will not attempt to climb the rose plant.
Groundcovers are often planted on the soil in place of grass. Celmatis itself is often considered a groundcover when it is left to sprawl over the ground rather than trained up a trellis. Examples of groundcovers that grow well around clematis include lamb's ear, low-growing daylilies such as stella de' oro, irises, creeping thyme, lady's mantle, vinca, stonecrop, strawberries, alpine spiraea, fleeceflower, crownvetch, lungwort, pinks, geraniums, sweet woodruff, wintergreen and forsythia. In areas where the ground is partially to fully shaded, hostas or lilies of the valley make good groundcovers around clematis.