What to plant with roses – these 5 companion plants stave off blackfly, hide bare stems and attract beneficial insects

Peak blackfly season is just weeks away, and roses can quickly fall victim to the fast-spreading aphid species. Knowing what to plant with roses can help to keep numbers at bay, though – and there are a fair few other companion plants for roses that offer alternative benefits, too.

One of the best ways to get rid of blackfly on plants is to adopt a few companion planting ideas. That can mean pairing your roses with scented plants that keep aphids away, planting them next to shrubs that attract beneficial insects, or even planting groundcover plants that hide the lower bare stems.

To give you some rose companion planting inspiration, I've rounded up a list of things you should plant with roses (especially before blackflies get there first!).

1. Lavender

Learning how to grow lavender has so many benefits, from attracting pollinators to adding a touch of aromatherapy to your garden.

As luck would have it, blackflies hate the smell of lavender. It’s a pest-repellent plant that not only deters blackfly, but hides the fragrance of roses from it, too. It makes sense, then, that you should plant lavender with roses.

‘Lavender is an exceptionally good companion plant for roses,' says Lucie Bradley, gardening and greenhouse expert at Easy Garden Irrigation. 'Not only does its strong aroma mask the scent of the roses, making them hard to locate, but it also produces high levels of essential oils, including linalool and camphor, which are natural pesticides.'

If you'll be planting larger shrubs, it's a good idea to use a garden spade like the McGregor Carbon Steel Digging Spade from Argos.

Where to buy lavender:

• Crocus: Lucie recommends compact varieties like Lavender 'Hidcote', which should be planted around 60cm away from the base of your roses to prevent overcrowding.
• Thompson & Morgan: Lavender 'Devonshire Compact' is low-growing with a neat, compact habit.
• YouGarden: This Fragrant Lavender Collection includes 10 garden-ready 'Hidcote' lavender plants.

2. Catmint

Nepeta, known more commonly as catmint, is another pest-repellent perennial that makes a brilliant companion plant for roses.

‘It produces a chemical compound called nepetalactone, which acts as a natural pest deterrent to blackflies, ants and Japanese beetles,’ Lucie explains. ‘With Nepeta planted amongst your roses, you also benefit from its long blooming period, which enables it to act as a natural repellent from late spring through to early autumn.’

Catmint is also one of the best ground cover plants for preventing weeds, which will take a lot of the maintenance out of caring for roses. It's worth feeding your roses in spring to give the blooms a boost, though. Phostrogen Toprose Rose and Shrub Food is a bestseller at Amazon, and it can prevent discolouring and leaf drop, too.

Where to buy catmint:

• YouGarden: Nepeta 'Neptune' is a compact variety that produces lavender-blue flower spikes in the summer.
• Gardening Express: The white flowers of Nepeta 'Snowflake' complement pink roses for a romantic look.
• Crocus: Nepeta 'Cat's Pajamas' is a beautiful dwarf catmint variety, perfect for planting next to roses.

3. Marigolds

It isn’t just about repelling blackflies – if you’re wondering what to plant with roses, it’s wise to choose varieties that encourage their natural predators, too.

I always say that marigolds are superhero flowers in the garden for all of their aphid-repellent properties, but they’ll also attract the predators of blackfly.

‘One of the simplest and most effective ways to prevent aphids is by encouraging their natural enemies,’ says Tessa Cobley, plant pest expert and owner of Ladybird Plantcare. 'Ladybirds, lacewings and other beneficial insects are voracious aphid predators and can help keep populations under control.’

Marigolds are really easy to plant, but a sturdy hand trowel like the Spear & Jackson Elements Carbon Hand Trowel from Amazon can make the task even simpler.

Where to buy marigolds:

• Gardening Direct: Marigold 'African Sun Mix' produces orange, yellow and golden pom-poms that aphids hate and ladybirds love.
• B&Q: This 6-pack of marigold bedding plants is a great starter collection.
• Thompson & Morgan: Marigold 'Strawberry Blonde' is a beautiful variety (the flowers are almost pink!).

4. Winter savory

Moving on from plants that deter blackfly, others keep rose problems like fungal diseases at bay. That’s where winter savory comes in, a perennial herb that tastes a bit like thyme.

‘Whilst its strong scent is great for repelling blackflies and other insects, winter savory also helps to reduce the chance of your roses suffering from powdery mildew and black spot due to its aromatic, sulphur-like compounds,’ Lucie explains. ‘It releases them into the air like a natural fungicide.'

Where to buy winter savory:

• Crocus: Order 9cm pots of winter savory.
• B&Q: Winter savoury in a slightly bigger pot (14cm).
• Amazon: Buy Gardeners Dream winter savory as an aromatic companion plant for your roses.

5. Lady's mantle

Lady’s mantle, or Alchemilla mollis, is a companion plant that serves an aesthetic purpose to roses. It’s a brilliant filler plant for sparse flower beds, and it’s a recommendation of Lucie’s to those of us wondering what to plant with roses.

‘This herbaceous perennial provides an attractive contrast in texture and form with its light green, scalloped-edged, furry leaves and clusters of greenish-yellow flowers,’ she says. ‘It also forms a good ground cover below your roses, helping to camouflage the lower bare branches.’

Where to buy lady's mantle:

• Crocus: Order Alchemilla mollis for vibrant, scalloped foliage and green flowers.
• J. Parker's: A pack of five Alchemilla mollis plants.
• Thompson & Morgan: Another brilliant place to buy Alchemilla mollis plants.

What you'll need

So there you have it! Pairing your roses with the right plants is a simple, natural way to keep them blackfly and fungal diseases at bay and protect your blooms without relying on harsh chemicals.