Companion plants for knockout roses

Underplanting Roses – Companion Plants for Roses

Roses need friends or companion plants around them for various reasons, including pest and disease control, longer season of interest and aesthetics. Below are some basic rules to follow when pairing your favorite roses with other plants.

  • Growing roses by themselves is an open invitation to the pests and diseases that favor roses. Roses are healthier when provided with companion plants which help repel destructive bugs while encouraging beneficial insects. For instance, Alliums repel aphids, weevils, borers and moles. Geraniums repel Japanese beetles, aphids and other rose beetles. Marigolds help repel harmful nematodes and many pests, etc.
  • Underplanting your shrub roses with a succession of flowers will reinforce the beauty of their romantic blooms and extend the flowering season of your mixed border. Start with low-growing spring bulbs such as snowdrops, crocus, grape hyacinths, scillas, anemones and narcissi. They will provide color to your rose borders at a time when your roses are not at their best.
  • Roses do not like too much competition and it is recommended to surround them with plants that are not too aggressive or invasive as they might overpower your roses. Companion plants should be planted at least 12 in. (30 cm) away from your roses so that their roots are not disturbed
  • Make sure you maintain good air circulation to prevent attacks from insects and diseases.
  • There is a wide range of companion plants that will bring out the best qualities of your roses and share their space with a serene balance. Make sure you select any ornamental grasses, perennials, annuals or shrubs that have the same growing requirements as your roses. Roses do best in full sun and well-drained soil. Once established, roses have average water needs and require regular fertilization to promote new blooms. Their companion plants should share similar water, fertilizer, and pesticide treatments.
  • Texture, color, and form are also important in the selection of companion plants. Plants with tall spires complement the wide, cup-shaped flowers of roses, while perennials and shrubs with pale green, silver, or purple leaves accentuate the sumptuous rose blossoms.

Rose ‘Crocus’ & Phacelia Tanacetifolia

Rose ‘Anne Boleyn’ & Viola

Rose ‘Graham Thomas’ & Digitalis purpurea

With such a multitude of companion plants to pair your roses with, you are sure to find several combinations that will enhance your landscape and please your eye!

  • Great Rose Companion Plants: Low-growing Spring Bulbs
  • Great Rose Companion Plants: Alliums
  • Great Rose Companion Plants: Geraniums
  • Great Rose Companion Plants: Nepeta, Salvia and Lavandula
  • Other Colorful Rose Companion Plants
  • Great Foliage Plants as Rose Companions


“COMPANION PLANTING” — the theory that certain plants benefit each other when grown in close proximity — has proven an effective means of pest-control here at A Garden for the House. Last summer, rabbits immediately stopped munching my cosmos and zinnias after I edged the plants with fragrant lavender. And onions, when planted around the vegetable beds, have surely repelled moles, voles and certain insects, too. Now, what other plants are thought to aid each other in the garden?
COMPANION PLANTS:
Allium (onions, chives, garlic, shallots). Plant near roses, fruit trees, carrots, lettuce, tomatoes, broccoli, and other vegetables. Deters aphids, weevils, moles, fruit-tree borers. Protects roses from mildew, black spot and aphids.

Basil. Plant near tomatoes or asparagus. Repels aphids, flies, mosquitoes and spider mites; controls the tomato hornworm and asparagus beetle.

Beans. Plant near beets, carrots, cucumber, corn, eggplant, potatoes. Encourages growth by adding nitrogen to soil; is reported to control the Colorado potato beetle.

Borage. Plant around tomatoes, strawberries, fruit trees. Repels the tomato hornworm; attracts honeybees.

Castor Bean. Plant near vegetables to thwart moles. Do not, however, mistake the castor bean as edible; all parts of the plant are poisonous.

Celery. Plant near broccoli, cabbage, leeks, tomatoes, cauliflower. Deters the white cabbage-moth.

Coriander. Benefits all vegetables by repelling aphids.

Cosmos. Plant between rows of corn. Thwarts the corn worm (see comment #25 below).

Cucumber. Grown up cornstalks, the prickly vines of the cucumber discourage woodchucks and raccoons.

Fennel. Plant near tomatoes. In reader Karin’s experience (see comment #25 below), tomato hornworms devour the fennel, and and leave the tomatoes alone.

Geranium. Plant near cabbage, corn, grapes, roses. Repels cabbage worms; may thwart Japanese beetles.

Horseradish. Grow near potatoes, to discourage Colorado potato beetle.

Hyssop. Locate near cabbage and grapes; deters the cabbage moth.

Lavender. This is my favorite repellent. Protects vegetables and flowers from rabbits and woodchucks.

Leeks. Plant near celery, carrots and onions. Repels carrot flies.

Marigold. Plant near tomatoes, potatoes, eggplant, roses. Deters a wide range of harmful insects.

Nasturtium. Plant near cucumbers, squash, other veggies, and fruit trees. Repels cucumber beetles, white flies and squash bugs. Deters fruit tree borers.

Oregano. Plant near broccoli. Repels white cabbage moth.

Parsley. Grow near asparagus, carrots, tomatoes, roses. Deters carrot fly and beetles.

Pennyroyal. Place near broccoli, brussels sprouts, cabbage. Thwarts ants and cabbage maggots.

Pyrethrum. Plant in both vegetable and flower gardens. Impedes aphids, leafhoppers, ticks, pickleworms and cabbage worms. Repels the dreaded iris borer.

Radish. When you sow vegetable seeds directly in the garden, be sure to sow radish, too. It sprouts quickly, insects get used to the taste, and therefore leave your other, more-cherished seedlings alone.

Rosemary. Plant near carrots, cabbage, beans. Restrains carrot flies and cabbage moths.

Rue. Reportedly repels Japanese beetles.

Sage. Plant near carrots and others. Fends off carrot flies, cabbage moths, ticks.

Soybeans. Adds nitrogen to the soil, a benefit for all heavy-feeders. A possible deterrent for the Japanese beetle.

Summer Savory. Aids beans by frightening the bean beetle.

Thyme. Plant near cabbage to control flea beetles, cabbage maggots, and cabbage moths.

Does companion planting appeal to you? Let me know, in the comments field below.

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For love and luck, the power of roses and lavender

The gloriously scented and colourful combination of lavender and roses are cornerstones of many English gardens. Revered for their fragrance, both plants have ancient origins and are known for their medicinal properties that soothe the nervous system, reduce stress and promote restful sleep, making them perfect companions for any garden or garden visitor looking for moments of calm.

In the language of flowers, roses symbolize love but in pre-Victorian times you were more likely to find them on your dinner plate than in a vase. Traditionally grown for their nutritional and medicinal value, apple-scented rose leaves were once brewed as tea, rose petals coloured salads and rosehips were cooked into sweet syrups packed with vitamin C, ascorbic acid and iron. For people battling anaemia, rose hips contain the perfect balance of nutrients. Aromatherapists and perfumers prize the heady scent of roses too; rose is soothing to the nervous system and, according to folklore an ‘expert mender of the cracks in broken spirits’.

This ancient flower which, according to fossil evidence, is 35 million years old was probably first cultivated by the Chinese 5,000 years ago. Today, the bloom, colour and perfume of roses remain a firm favourite with gardeners and the lovers alike.

Lavender too enjoys an ancient history. Named from the Latin lavare, to wash, the ancient Romans used lavender in their bath water as a perfume as well as for its therapeutic properties to reduce-stress, headaches and insomnia. The Arabs were the first to farm the plant, prizing it for its ability to clean deep wounds and encourage healing, and for its fragrance; they were the first to develop distilleries to extract essential oil of lavender.

In England, lavender’s protective, love-inducing and relaxing properties helped commoners and kings alike; Queen Elizabeth I demanded fresh lavender at her table throughout the year and rich and poor used it to scent bed linens and clothing. It was hung above the door to protect against evil spirits and added to baths to drive evil spirits and demons from cranky children and to rejuvenate adults. In the mid-1500s in his work ‘A New Herball’ Turner claims that washing your head with lavender was an effective treatment against mental illness. Lavender was also used in England as an antiseptic wash during surgery and for deep wounds right up to World War I.

It’s no wonder that there is magic associated with lavender too. Used to drive away demons and to summon faeries on midsummer’s eve it was often used for spells, amulets and charms to attract love.

These love laden plants, so rich with scent and healing properties, remain perfect companions in our gardens contributing not only to the beauty of our private spaces but to a sense of deep and restful wellbeing.

Find your perfect roses and lavender in National Garden Scheme gardens this summer

Top image: Hestercombe Gardens, Taunton

What to grow with roses

The shapes, colours and scents of roses are undeniably beautiful, but their season can be short. If you combine roses with other plants, you’ll not only highlight the beauty of their flowers – you’ll also give your borders a much longer season of interest, too.

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Planting other plants with roses also attracts beneficial insects and those that will prey on pests; some plants are also said to help reduce diseases such as black spot and mildew.

Nowadays, many rose gardens that were traditionally home to roses in dedicated beds are now combining them with spring bulbs, biennials, perennials and even grasses for added interest.

A combination of these plants provides colour before the roses bloom, accentuate their beauty when they’re in flower in midsummer, and provide further colour and structure once the roses have faded.

Discover 10 beautiful roses to grow.

Here are some of our favourite companion plants for roses.

If you combine roses with other plants, you will not only highlight the beauty of their flowers – you’ll give your borders a much longer season of interest, too.

Spring bulbs

Many roses are pruned in winter and aren’t very attractive at this time. Underplant with a succession of spring bulbs – snowdrops, crocus, grape hyacinths, narcissi, early-flowering tulips and late-flowering tulips, before the roses start to bloom.

Purple-pink tulips

Alliums

Alliums come up year after year and their violet, globe-like flowers look great with early roses. Alliums and other members of the onion family are said to ward off aphids, prevent rose black spot and even make the scent of roses stronger.

Purple orbs of allium flowers

Erysimum ‘Bowles’s Mauve’

The perennial wallflower, Erysimum ‘Bowles’s Mauve’, starts flowering in spring and continues through summer – a great foil for white, pink, crimson or red roses. It then continues to flower for the rest of the year – keep deadheading it.

Mauve wallflowers

Lilies

Most lilies come into flower just as the first flush of roses is beginning to go over. Tall, blowsy Lilium regale bear beautiful, white, pink-flushed flowers and they pump out a delicious fragrance, too. They also make good cut flowers.

Pink-flushed, trumpet-shaped white lilies

Foxgloves

White, pink and purple foxgloves are at their peak in midsummer, coinciding with many roses, and their spire shapes contrast beautifully with them. The peachy foxglove ‘Sutton’s Apricot’ looks particularly lovely with creamy, pink or crimson roses.

Spires of magenta-centred, pale-pink foxglove flowers

Hardy geraniums

Roses look great underplanted with hardy geraniums. Purple-blue geraniums like ‘Rozanne’ look good with many colours of rose, while pale pink Geranium x oxonianum ‘Wargrave Pink’ looks especially pretty with crimson roses such as ‘Darcey Bussell’.

Small, pink hardy geranium flowers

Salvias

Salvias come in a range of colours and make great partners for roses – they’re long-flowering and their spire shapes give contrasting structure and interest. They also attract a huge number of beneficial insects and it’s said that they help to keep mildew and blackspot at bay.

Purple salvias

Verbascums

Verbascums begin flowering in May and are still going when roses begin to bloom. They come in a wide range of colours, including yellow, white and peachy orange (such as ‘Clementine’, shown here). Their tall spires contrast beautifully with roses.

Peachy-orange verbascums

Nepeta

Nepetas form a carpet of blue and look especially good with pink, crimson, red and even yellow roses. Nepeta ‘Six Hills Giant’ can be quite vigorous, so if you’re short on space, go for Nepeta racemosa ‘Walker’s Low’. They attract many pollinators, especially bees and hoverflies.

A mauve carpet of nepetas

Penstemons

Penstemons not only look great with roses – they also keep the show going once they’ve finished blooming, often well into autumn. In shades of purple, pink, crimson or white, they look lovely with apricot, cream and pink roses.

Pink-fringed, white penstemons

Lavender

English lavender, Lavandula angustifolia, especially the dark purple-blue ‘Hidcote’ looks wonderful with apricot, pink, crimson or red roses. When not in flower, it offers neat mounds of evergreen, aromatic foliage.

Advertisement A swathe of lavender blooms

Deadhead frequently

Be sure to deadhead your roses frequently – it will encourage more blooms, keeping the display going for longer.

Lime alchemilla

Other plants to grow

  • Alchemilla mollis
  • Campanulas
  • Grasses such as Stipa tenuissima
  • Gaura lindheimerei
  • Asters

If you’re wondering what to plant with Knockout roses, this 3 – 4 foot high x 3 – 4 foot wide shrub can be planted with just about any ground cover, tree, shrub, vine etc., suitable to the same growing conditions. Because this plant is not only hardy to zone 5, but also a very tough rose, get creative combining it with other plants.

Below are several plant lists in which I include the usage of the Knockout rose. Take a look…

Contemporary Front Planting

For a contemporary look, keep the planting plan simple and without fuss. By using no more than 4 different types of plants, with only one cherry red Knockout rose, I was able to give a little color to an otherwise linear and textural composition.

As you can see in the photo, foliage textures combine well. I used several bluish green festuca grasses (clumping fescue) as a rhythmic ground cover, surrounded by what will grow and be clipped/maintained as a low evergreen hedge (Pittosporum ‘Elfin’). This low evergreen hedge serves as a more disease resistant substitute to a more common choice, like boxwood.

Though still small, the course texture of the evergreen Magnolia’s foliage, which is a shiny green on top, with a reddish beige colored underside, adds a pleasant feel with the Knockout rose’s cherry red color.

Plant List:

  • Pittosporum ‘Elfin’
  • Festuca ‘Festina’
  • 1 Rosa ‘Knockout’ red
  • Magnolia ‘Little Gem’

Lawn Border Planting

In this planting I used some reddish/burgundy foliage, (which is very attractive and strong) with the red flowering Knockout rose. Two that I used are Loropetalum, with purplish leaves, and groundcover, Ajuga.

The blue green new growth of the Knockout rose, and the red flowers are very nice with succulent, Sedum ‘Autumn Joy,’ which has rosy red flowers in late summer into fall. The blue grass, Helictotrichon, is also a nice fit. For warm flowering colors, the orange flowering Abutilon ‘Victor Reiter’ is nice nearby. Repeated grass, Carex testacea, has an olive and orange blade, that adds interest. Of course, the pleasing flowers in purples and blues of the Scaevola, lavender, Verbena, Ajuga etc., adds a very nice feel.

Plant List:

  • 2 Rosa ‘Knockout’ red
  • Verbena bonariensis
  • Sedum ‘Autumn Joy’
  • Ajuga ‘Catlin’s Giant’
  • Abutilon ‘Victor Reiter’
  • Lavender
  • Citrus
  • Apple tree espalier
  • Hemoracallis ‘Stella de Oro’
  • Carex testacea
  • Helictotrichon sempervirens
  • Salvia uliginosa
  • Lysimachia nummularia ‘Aurea’
  • Scaevola ‘Blue Wonder’
  • Convolvulus mauritanicus
  • Loropetalum
  • Trachelospermum jasminoides
  • Ferns
  • Fuschia thymifolia

Formal Garden Planting

This planting bed is part of a formal garden. The rectangular shaped bed is surrounded on all sides with a low boxwood hedge, kept around 16 inches high. Within, are 2 citrus containers, and 3 cherry red Knockout roses.

Plant List:

  • Buxus sempervirens ‘Green Beauty’
  • Meyer Lemon trees, in containers
  • 3 Rosa ‘Knockout’ red

Dry Creek Fountain Area

In this recent planting which includes a dry creek bed made with San Pablo cobble – the tropical effect of the already existing tree ferns, ferns and nearby birds of paradise – which I wanted to retain, became the basis for the final planting plan.

As you can see from this photo angle, I used a red Knockout rose and right away there is pop in a sea of calming green. (Here’s my link to Amazon if you’re looking to buy online. 🙂

This is a great plant choice for relying on continued bloom in a mixed planting. It’s not a grandma rose, though I hate to say, some of the pictures of the flowers may make it look that way! No, my interest in this rose is really based on floral performance and reliability, which it delivers superbly (so far) on both!

Plant List:

  • 3 ‘Knockout’ roses
  • 2- Existing tree ferns
  • Existing ferns (Nephrolepis cordifolia – thinned)
  • Berberis T. ‘Concord’
  • Scaevola ‘Blue Wonder’
  • Aucuba japonica
  • Festuca ‘Siskiyou Blue’
  • Carex tumulicola
  • Carex ‘Frosted Curls’
  • Ajuga ‘Purple Torch’& Ajuga ‘Catlin’s Giant’
  • Hemorocallis (yellow and red)
  • Ficus pumila

Container Planting on Deck:

  • 1 Rosa ‘Knockout’ red
  • Red Weigelia
  • Lavender
  • Climbing rose
  • Abutilon

As you can see, this is an extremely versatile rose that combines well. I am amazed with its’ carefree blooming nature and the performance so far, even as I have stretched to locations of part shade and containers. Stay tuned as I’m going to try a few different pruning techniques this winter, to see how this affects bloom performance the following season. To learn more about “Knockout”, check out this post.

Happy Gardening!

p.s: Unfortunately, I’ve found that it’s not always easy to get your hands on the Knockout at your local garden center, (“when you want it.”) Here’s my link to Amazon; a couple of retailers have 1 gallon sizes. And finally, here’s a blog post (a review actually) about rose pruning gloves.

A visitor to the garden last summer asked why we grew so few roses. I explained that, out of the many varieties we’d tried, a large proportion had turned out to be too prone to fungal diseases for us to stick with them.

We don’t want to use chemicals at Perch Hill and certainly not fortnightly, the routine usually required to keep roses free of black spot and mildew. Our visitor then confirmed what I had read – that if you underplant roses with salvias, the roses will stay healthy. Alliums have the same reputation.

We’d just finished restoring a barn, and on the south side had created a new garden. We were about to fill the central six beds with herbs and put roses in the larger beds around them. We decided to experiment with the rose and salvia companion planting, so propagated all the salvias we had (see box, right – this is very easy to do and, if you have a propagator with basal heat, there’s still time this year).

In January, the roses went in, mainly strong forms in unusual colours, chosen for good vase life and powerful scent, such as the brown Hot Chocolate, blue-purple Rhapsody in Blue, bright pink Wild Edric and the dark and velvety crimson Munstead Wood and Darcey Bussell. Once the tulips were over in May, all our salvia cuttings were planted in between.

Credit: ©Jonathan Buckley

Well, it’s hats off to salvias, as all but Munstead Wood are still pristine now, so late in the year, without a sniff of fungicide. They’re still flowering and have done so (some having a break and then restarting) since the middle of June. That’s in their first year after planting, so it seems that it’s not just alliums that keep roses good and strong; the aromatic salvia family also do a great job.

Pretty partnerships

In terms of overall performance among the salvias, ‘Amistad’ – with its ink-black calyx and indigo flower – has stolen the show. It’s been in flower since May and is as covered in bud now in October as it was at the end of spring. It’s a truly marvellous plant that no garden should be without. In fact, it’s such a strong grower, it’s slightly drowned out the much slower China roses, such as ‘Mutabilis’ and the species R. glauca with which it is planted. It will go in a different place next year.

China rose ‘Mutabilis’ Credit: Getty Images

The most successful partner we’ve had with ‘Amistad’ has been the green-flowered pea species Lathyrus chloranthus, which, unlike its cousins the sweetpeas, is still happily clambering up and through the salvia, covered with new growth and plenty of flowers.

Better with roses are the lower-growing, spreading salvia varieties such as ‘Stormy Pink’, the similar-coloured ‘Krystle Pink’, along with the luscious crimson ‘Nachtvlinder’.

We also love the coral-pink and apricot ‘Tutti Frutti’, and similar-coloured but slightly larger-flowered ‘Señorita Leah’. With all of these, you can tuck the salvias in under the skirts of the rose. They’ve been a triumph, as well as the larger-growing, but not too drowning, rich, deep pink, S. microphylla ‘Cerro Potosí’.

Salvia microphylla ‘Cerro Potosi’ Credit: ©Jonathan Buckley

We’ve also had two good reds: ‘Wendy’s Wish’ is lovely for the fresh green of its stems, calyces and crenellated foliage, an excellent contrast to the flower colour; and ‘Jezebel’, which has slightly smaller flowers; these stand out strongly from the dark crimson calyces and stems.

Potted success

In the same garden, we’ve also had salvias in pots, and they’re all worth repeating. We have the true-blue species Salvia patens topping an old trough filled with Pelargonium ‘Marion Saunders’ and the felted, silvery foliage plant Plectranthus argentatus. The salvia and pelargonium are still covered in flowers.

Among the roses we also have a large pot containing Salvia ‘Dyson’s Gem’, with the royal blue Salvia ‘Blue Note’ creating a skirt around a purple bell vine (Rhodochiton) climbing over a woven silver birch tepee. This also creates the framework for a pot filled with the huge-leaved Salvia macrophylla. This is on the same scale as ‘Amistad’, by now at least five feet tall and also looking good growing with the purple bell vine.

In another pot I love the simple mixture of Salvia ‘Cerro Potosí’ planted with Nicotiana ‘Lime Green’. In previous years – like our roses – the green-flowered tobacco has been clobbered by mildew, but not this year. It remains utterly pristine.

Our experiment suggests that the line on salvias being the best natural fungicide turns out to be true.

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