This post about companion plants for roses (especially shrub roses) is the third in my series on companion plants.
Companion plants bring out the best characteristics of other plants and help to make up for any weaknesses. They mingle in, around, above or below other plants. Good neighbours, they will not compete too aggressively for food, water or space. To find out more about what makes a plant a good companion, take a look at the first post in the series on astrantias.
Why do roses benefit from companion plants?
When I was younger it was fashionable in the UK to grow groups of roses without any companion plants in island beds or borders. Most of us will have seen roses grown like this in parks and public spaces looking sorry for themselves soon after the first flush of flowers have faded.
While it is true that roses make good companions for each other (shrub roses and climbing roses being a classic mix), roses often perform better when grown with other shrubs, perennials, herbs, bulbs, annuals and climbing plants in mixed borders.
Few roses are genuinely ever-blooming; most Old Roses only flower once in early summer. Companion plants make the garden look good for longer, hide a multitude of sins and will help keep the roses healthy.
Reasons for growing roses with companion plants include to:
- Provide interest before the roses have leafed out, when the roses are resting between flushes of bloom and later in the season
- Add contrasting textures, flower forms and colours
- Layer on the scent
- Fill out the garden and provide ground cover
- Add height, rhythm and movement
- Create structure (e.g. box, yew)
- Hide any defoliation as the season progresses
- Attract a broad community of beneficial insects that prey on aphids
- Support bees, butterflies, birds and other wildlife
- Avoid a monoculture where pests and diseases can flourish
What is a monoculture?
Monoculture means the cultivation of a single crop or type of plant in a particular area. Any monoculture naturally attracts and supports pests, for example, lots of roses grown together make a great home for aphids and beetles. It’s like filling a street with ice cream parlours and sweet shops but hoping to keep away anyone who has a sweet tooth.
Monocultures encourage the spread of diseases such as blackspot and powdery mildew in roses. Spreading out the roses and interspersing other companion plants between them will help lessen the risk (think of it as keeping social distance). Any inclusion of disease-prone rose varieties will make it more likely that other, more healthy roses will succumb too, so remove any badly affected plants.
Which plants make the best companions for roses?
Roses generally do best in full sun and their companions should enjoy the same conditions. It makes sense to avoid the most invasive plants; greedy ones that will take up a disproportionate amount of water and nutrients; and any that will crowd or shade out the roses. Always check the height and spread of a plant before buying.
Beyond that, experiment with anything that takes your fancy. Many rosarians lean towards more modest companions that will let the roses shine, but some of the loveliest gardens mix in showy flowers knowing their roses will hold their own among them.
Companion plant list for roses
There are relatively few cottage garden style plants that do not make good companions for roses, but here are some of my favourites:
Alchemilla mollis (Lady’s mantle)
Centaurea montana (Knapweed)
Culinary herbs – chives, dill, oregano, parsley, rosemary, thyme
Dianthus carthusianorum (Hardy pink)
Lamprocapnos spectabilis (Bleeding heart)
Leucanthemum x superbum (Shasta daisy)
Lychnis coronaria; Lychnis chalcedonica
Polemonium (Jacob’s ladder)
Salvia nemorosa; Salvia x sylvestris
Sedum (border types)
Stachys byzantina (Lamb’s ears); Stachys macrantha
Tanacetum parthenium (Feverfew)
For year to year variation, mix in annuals, biennials and short-lived perennials:
Angelonia (Summer snapdragon)
Calendula officialis, Tagetes erecta (Marigold)
Calibrachoa (Million bells)
Delphinium consolida (Larkspur)
Hesperis matronalis (Night-scented gilliflower)
Lysimachia atropurpurea ‘Beaujolais’
Nicotiana (Flowering tobacco)
Scabiosa, Knautia (Scabious)
Shrubs – Daphne, Deutzia, Lavatera, Lilac, Philadelphus, Spirea, Weigela, etc
Grasses – often seen in contemporary rose gardens
Green backdrop/dividers – Boxwood (including topiary) and tall Yew hedges
Bulbs (alliums, spring bulbs)
Climbers – Clematis, climbing or rambling roses
Painting with flowers
Companion plants can add shades of colour that roses lack or emphasise a specific colour palette. For example, use Salvia nemorosa ‘Caradonna’ to add brushstrokes of purple-blue, Salvia x sylvestris ‘Snow Hill’ for white, and for pink try Salvia x sylvestris ‘Pink Dawn’. Paint the garden red with Papaver oriental ‘Beauty of Livermere’ or scatter dots of orange and yellow with Papaver cambricum.
Delphiniums will inject towers of pure blue, electric blue, shades of purple, pink, cream and white. Use Eryngium for spikes and ruffs and one of my favourites, Leucanthemum x superbum ‘Old Court’, to add scribbles.
- Gardeners who are new to growing roses may be looking for one magical companion plant they can add to deter all pests. Good luck with that! Instead, aim for a wide range of companion plants to attract a broad community of insects including ones such as spiders and ladybirds that will naturally control the insects you don’t want.
- In more expansive gardens, site several plants of the same variety together in clusters, swathes or waves of colour; in small gardens, single plants will look lovely once they are established.
- Leave yourself access to deadhead, summer prune roses and cut back companions during the season.
- Don’t crowd your roses. Companions should be planted 30 cm / 1 ft away from the base of the rose, or more depending on their eventual size.
- This is not a low-maintenance style of gardening. Some of the plants often recommended as companions for roses may be borderline invasive in your part of the world – Achillea, Alchemilla mollis, Centaurea montana, Japanese anemone and even Nepeta ‘Six Hills Giant’. Be prepared to actively intervene to keep your garden well-balanced.
- Large trees make poor companions for roses other than the most vigorous of ramblers. A rose growing under a tree would almost certainly be happier elsewhere.
If you enjoyed this post, check out my guide to using hardy geraniums as companion plants.