Begin building this layout by placing a smooth silk or satin table runner down the center of the dining table to anchor the display. Position a sturdy 12-inch metallic or ceramic pedestal urn directly in the center of the table runner. Insert a soaked block of floral foam securely into the urn basin, taping it in place with waterproof floral tape. Weave long sprigs of silver dollar eucalyptus and Italian ruscus around the base of the foam block, allowing several leafy stems to drape downward along the pedestal sides. Insert large white hydrangeas low into the foam grid to establish a dense, supportive base structure. Fill in the arrangement with long-stemmed blush garden roses, spray roses, and carnations, angling stems outward to build a rounded, overflowing shape. Place four small cut-glass votive holders containing LED or wax tealights symmetrically around the pedestal base to illuminate the cascading greenery from below.