When it comes to companion plants for lilacs, there are many options. For a classic look, try planting peonies and daylilies near your lilac bush as they will create an attractive contrast of colours and textures. Adding ornamental grasses such as muhly or switchgrass can give the garden a sense of movement and texture. If you're looking for foliage interest, consider adding evergreen shrubs like boxwood or Japanese holly to bring year-round colour to your garden bed. Finally, if you'd like some additional colour in springtime when the lilacs bloom, then add spring bulbs such as tulips or hyacinths around the base of the shrub to provide pops of bright blooms during this season. With these companion plants, you'll be sure to have a beautiful landscape design!