Many of us gardeners plan our gardens around our roses. I used to think that meant giving them a bed of their own, bare soil raked smooth, nothing touching them. It looked tidy. It also looked lonely.
Roses look better when grown with other plants instead of being segregated in a rose garden with only bare soil for company.
Companion plants bring out the best characteristics of roses, especially shrub roses, and help to make up for weaknesses. While they mingle around, above or below the roses, they should not compete too aggressively for food, water or space. Choose plants with similar growth requirements. Roses generally do best in full sun and their companions should enjoy the same conditions.
When I was younger it was fashionable to grow groups of roses without any companion plants in island beds or borders. Many of us have seen roses grown like this in parks looking sorry for themselves soon after the first flush of flowers has faded. Few roses are ever blooming. Most Old Roses flower once in early summer. Companion plants make the garden look good for longer, hide a multitude of sins and help keep the roses healthy.
Extend the season by combining annuals, perennials, grasses and shrubs. Provide interest before the roses have leafed out, when they are resting between flushes of bloom and later in the season. Add contrasting textures, flower forms and colours. Place spiky blooms like foxglove or grasses beside rounded rose bushes. Add bold leaves like brunnera or light flowers like babys breath.
Layer on the scent. Culinary herbs such as chives, dill, oregano, parsley, rosemary and thyme shape a space and do useful work. Members of the Allium family are reported to increase the perfume of roses and help prevent black spot. Onions repel aphids, weevils, borers and moles. Garlic repels aphids and thrips and helps fight black spot and mildew. Chives repel many pests. Basil repels aphids and mosquitoes. Geraniums repel Japanese beetles, aphids and rose beetles. Marigolds discourage harmful nematodes and act as a trap plant for slugs.
Attract beneficial insects that prey on aphids. Support bees, butterflies, birds and other wildlife. Hummingbirds eat aphids from rose bushes as they cruise for nectar. Avoid a monoculture where pests and diseases can flourish. Monoculture means the cultivation of a single crop or type of plant in a particular area. Roses grown together in large numbers create a home for aphids and beetles. It is like filling a street with ice cream parlours and sweet shops but hoping to keep away anyone who has a sweet tooth.
Add structure with evergreen shrubs such as boxwood, sweet box, holly or yew. Green backdrops like Buxus and tall Yew hedges create shape. Provide ground cover, but do not crowd your roses. Install companions 12 to 18 inches away from roses to avoid disturbing the roots. Plant at least 30 cm or 1 ft away from the base of the rose, or more depending on eventual size. Avoid plants that crowd or provide too much shade. Roses do not like to compete for water, nutrients or sunlight.
There are few cottage garden plants that do not make good companions for roses. Achillea, Alchemilla mollis, Aster, Baptista, Campanula, Centaurea montana, Daylily, Delphinium, Dianthus carthusianorum, Echinacea, Eryngium, hardy geranium, Lavender, Lilium, Nepeta, Papaver, Peonia, Phlox paniculata, Salvia nemorosa, Sedum and Veronicastrum virginicum all work well.
For perennials that bloom over a long period, consider Aster, Campanula, Echinacea, Nepeta, Digitalis, Garden Phlox, Agastache, Alchemilla, Lavandula, Dianthus, Salvia, Veronica, Sedum and Achillea. Delphiniums add towers of blue, purple, pink, cream and white. Roses do not offer blue, so plant delphinium, veronica, iris and bluebeard if you want that colour in the border.
Grasses and upright foliage add height and movement. Blue Oat Grass, Fountain Grass, Miscanthus and Switchgrass are common choices. Some gardeners prefer modest companions that let the roses stand forward. Others mix in stronger flowers knowing their roses will hold their own.
Tuck spring bulbs into rose gardens. Alliums and other bulbs provide interest before the roses have leafed out. Summer annuals such as alyssum, lobelia, lantana, petunias, Angelonia, Calibrachoa, verbena and Dianthus add colour and do not interfere with autumn cleanup.
Groundcovers can hide the bare lower stems of roses, particularly hybrid teas. Many are too aggressive. Choose plants that tolerate light foot traffic, such as violets, sedums and strawberries. Low growers like woolly thyme or blue star creeper can work. Consider your maintenance practices and leave access for deadheading and summer pruning.
A cutting garden can sit beside your roses. Use babys breath, delphinium, peony, Shasta daisy, yarrow and Japanese anemone for arrangements. Companion plants add colours that roses lack or strengthen a chosen palette. Plant Papaver oriental for red or Salvia nemorosa for purple blue. Use Leucanthemum x superbum for white contrast.
Leave room to deadhead and cut back plants during the season. This style of gardening requires attention. Large trees make poor companions for roses except for strong ramblers. A rose under a tree is usually happier elsewhere.
Beyond that, experiment. An informal approach to design offers many options. Roses make good companions for each other, but they often perform better when grown with shrubs, perennials, herbs, bulbs, annuals and climbers in mixed borders. This is a place to observe, adjust and try again next season.