Gardening in the UK can be an unpredictable adventure. One day it’s a drizzle, the next you’re basking in rare sunshine, and then it’s back to soggy shoes in the garden. But if you’ve got the right plants, your garden can thrive through it all, especially if you’re working with perennials. These long-lasting plants come back year after year, adding reliable color and structure to your beds and borders. But here’s a little-known secret: you can make your perennial garden even healthier and more beautiful through companion planting.
Companion planting isn’t just for the veg patch—pairing perennials together can work wonders, too. The right combinations can enhance growth, deter pests, attract beneficial insects, and create stunning displays that look good for months on end. It’s all about finding the perfect plant partners to create a garden that practically takes care of itself.
If you’re ready to transform your garden into a low-maintenance, high-impact haven, let’s dive into the nine best tips for companion planting perennials. I’ll also share 10 specific plant pairings that work wonderfully in UK gardens. These tips will help you build a more resilient, beautiful space, year after year.
1. Understand Why Companion Planting Works with Perennials
Companion planting is essentially about harnessing the natural relationships between plants to improve their health and your garden’s productivity. When it comes to perennials, these relationships are particularly powerful because the plants are in it for the long haul. Instead of needing to replant every year, you can build a long-lasting, interconnected garden community that works together.
Some perennials are natural pest repellents, others attract pollinators or beneficial insects, and a few improve soil health over time. Take lavender, for instance. Not only does it smell heavenly and attract bees, but it also repels moths, flies, and even deer (though deer aren’t as much of a problem in most UK gardens). I planted lavender along the edge of my rose border a few years ago, and the results were spectacular—fewer pests, more blooms, and a garden that just smells like a slice of Provence every time you walk past.
Another example is catmint (Nepeta), which makes an excellent companion for roses. Roses can be temperamental and are often plagued by aphids, but catmint acts as a natural deterrent for these pests. Plus, it adds a beautiful, soft blue haze that complements the roses’ vibrant blooms. After pairing these two in my garden, I’ve seen fewer aphid issues, and the combination of colors is absolutely stunning.
2. Choose Plants That Suit Your Local UK Climate
As any UK gardener knows, the weather here can be a bit… well, unpredictable. Whether it’s the cooler northern regions or the relatively mild south, the trick to successful companion planting is choosing plants that suit both your local climate and your garden’s specific conditions.
For example, in wetter regions like parts of Wales or Scotland, you’ll want to look for moisture-loving perennials. Astilbe is a great choice for these conditions—it thrives in damp, shady areas and pairs beautifully with hostas, which also love a bit of shade and moisture. I have a shady, slightly boggy corner in my garden, and after years of trying (and failing) to plant sun-loving perennials there, I finally embraced the shade. Planting astilbe and hostas transformed that sad patch into a lush, textured oasis. The astilbe’s feathery plumes provide height, while the hostas fill in with their broad, dramatic leaves.
On the flip side, if you’ve got a sunnier, drier garden (lucky you!), you can experiment with more drought-tolerant perennials like sedum and echinacea. Sedum, with its thick, succulent leaves, stores water, making it a perfect plant for hotter, drier spots. Paired with echinacea—a butterfly magnet that loves the sun—you’ll get a beautiful, pollinator-friendly combo that will keep your garden buzzing with life. I’ve tried this pairing in a sunny border near my patio, and not only do the bees love it, but the contrasting textures and colors create an eye-catching display from late summer into autumn.
3. Start with Classic Perennial Pairings
There are some perennial pairings that just work—plants that naturally thrive together, whether by complementing each other visually or by offering practical benefits like pest control or shade. If you’re new to companion planting or just want to keep things simple, start with these classic combinations. They’ve been tested by generations of gardeners and are particularly well-suited to UK conditions.
10 Great Plant Combinations for UK Gardens
- Roses and Geraniums (Cranesbill): Roses are the divas of the garden, often needing extra care and attention. But geraniums are the perfect laid-back companions, repelling pests like aphids and acting as natural ground cover to help suppress weeds. Plus, the combination of roses’ dramatic blooms with geraniums’ understated flowers creates a harmonious blend of color and texture. I’ve planted these two together for years and can honestly say it’s a match made in garden heaven.
- Lavender and Rosemary: These Mediterranean herbs are like the best of friends, thriving in similar conditions—well-drained soil and plenty of sun. Both plants repel pests and attract pollinators, making them a great choice for an herb garden or sunny border. I love planting them along pathways because their scent releases when you brush past, adding another layer of sensory enjoyment to the garden.
- Echinacea and Rudbeckia: If you want to create a garden that’s alive with bees and butterflies, this is the combo for you. Both plants love full sun and bloom from late summer into autumn, providing a long-lasting display of bright, cheerful colors. In my own garden, these two have become the stars of the late summer show, attracting pollinators and adding a splash of color just when other plants are starting to fade.
- Astilbe and Hostas: Perfect for shady, damp areas of the garden, these two perennials complement each other beautifully. Astilbe’s tall, feathery flowers add height and structure, while hostas provide lush ground cover with their large, bold leaves. I’ve planted these two in a neglected shady corner of my garden, and they’ve completely transformed the space into a peaceful, green retreat.
- Foxgloves and Ferns: Another great pairing for shady gardens, foxgloves add vertical interest with their tall flower spikes, while ferns bring a soft, natural texture to the undergrowth. I love this combination for woodland-style gardens where you want a natural, almost wild look. The foxgloves’ tall spires draw the eye upward, while the ferns create a calming, lush green base.
- Sedum and Asters: These two perennials love full sun and well-drained soil, making them ideal companions in drier areas of the garden. Sedum, with its fleshy leaves and clusters of star-shaped flowers, provides a striking contrast to the daisy-like blooms of asters. Plus, they both bloom late in the season, adding color when many other plants are winding down.
- Peonies and Catmint: Peonies are known for their show-stopping blooms in early summer, while catmint provides a low-growing companion that adds softness to the garden. The catmint also helps repel pests that might otherwise bother your peonies. I’ve planted this combination along the edges of my beds, and the effect is both practical and beautiful. The catmint’s lavender-blue flowers create a perfect backdrop for the peonies’ lush, full blooms.
- Alliums and Heucheras: Alliums, with their tall, globe-shaped flower heads, are a fantastic choice for adding vertical interest to the garden, while heucheras provide a lovely contrast with their low-growing mounds of colorful foliage. I’ve used this combination in my garden to create a striking contrast between the boldness of the allium flowers and the delicate, multi-colored leaves of the heucheras.
- Daylilies and Salvia: Daylilies are hardy, reliable perennials that bloom repeatedly throughout the summer, while salvia adds a touch of elegance with its spires of purple flowers. The combination of the daylilies’ bold, trumpet-shaped flowers with the salvia’s upright blooms creates a dynamic and eye-catching display in a sunny border. I’ve found that these two thrive together, providing color and structure for months on end.
- Bleeding Hearts and Brunnera: In shady, damp spots, bleeding hearts provide delicate, arching stems of heart-shaped flowers in spring, while brunnera brings bold, textured foliage and clusters of tiny blue flowers. This pairing adds a touch of romance to the garden, with the soft, graceful shapes of the bleeding hearts contrasting beautifully with the bold, heart-shaped leaves of the brunnera.
4. Incorporate Trap Plants to Keep Pests Away
Even in a perennial garden, pests can be a problem. That’s where trap plants come in handy—these are plants that attract pests away from your more valuable perennials, acting as a kind of sacrificial offering.
For example, nasturtiums are great for luring aphids away from other plants. I once planted nasturtiums near my delphiniums after an aphid invasion, and they worked like a charm. The nasturtiums took the brunt of the aphid damage, leaving my delphiniums looking as pristine as ever. Plus, nasturtiums are edible, so I often harvest the flowers for salads—two birds, one stone!
Another excellent trap plant is alyssum. This low-growing flower attracts beneficial insects like ladybirds, which feed on aphids and other pests. I like to plant alyssum around my daylilies and heucheras, and it helps keep the pests in check while adding a soft, fragrant carpet of flowers at the base of my taller perennials.
5. Rotate Your Perennials Every Few Years
Although perennials are meant to stay put for years, it can actually be beneficial to move them around every now and then. After a few years, some plants may start to struggle in the same spot due to soil depletion or pest buildup. Rotating your perennials can help refresh the garden and keep your plants healthy.
I learned this lesson when my beloved bed of phlox started looking tired after a few years. The flowers were smaller, and the plants just didn’t seem as vigorous as they used to be. So, I dug them up, divided the clumps, and replanted them in a different part of the garden, swapping them with echinacea from another bed. The following year, both the phlox and the echinacea bounced back stronger than ever, and my garden felt like it had been given a new lease of life.
6. Let Flowers Do the Work
Flowers aren’t just for looks—they can also pull double duty by attracting beneficial insects or repelling pests. Marigolds are an excellent example. French marigolds are particularly good at repelling nematodes and aphids, making them a great choice for planting among your perennials. I’ve scattered marigolds around my delphiniums and peonies, and they help keep the pests at bay while adding a vibrant pop of color.
Alliums are another flower that works overtime in the garden. Their tall, dramatic flower heads are not only stunning, but they also help repel pests like slugs and aphids. I’ve paired alliums with hostas in the shady parts of my garden, and the combination is both visually striking and practical—no more slug-ravaged hosta leaves!
7. Make the Most of Small Spaces
Even if you’re working with a small garden, companion planting can help you maximize your space. By pairing plants that complement each other in terms of height, color, and growth habit, you can create a full, lush garden without overcrowding.
For example, planting tall, vertical plants like foxgloves alongside low-growing ground covers like creeping thyme or ajuga allows you to layer your plants and make the most of every inch. I’ve done this in a narrow border along my fence, and the effect is stunning—tall, dramatic spires of foxgloves with a carpet of colorful ground cover below.
Another trick for small spaces is to use climbing plants like clematis. I’ve planted a clematis at the base of a shrub in my garden, and it climbs up through the branches, adding a second layer of color and texture without taking up any extra ground space. It’s like having two plants in one spot, which is a real bonus when you’re short on space.
8. Avoid Bad Combinations
Not all perennials are friendly neighbors. Some plants can actually inhibit each other’s growth or attract pests that harm their companions. It’s important to do a bit of research before planting to avoid pairing plants that don’t get along.
For example, bee balm (Monarda) is a beautiful, fragrant plant that attracts pollinators, but it’s also prone to powdery mildew. Planting it too close to other mildew-prone plants like phlox or roses can create a mildew nightmare. I learned this the hard way when both my bee balm and phlox ended up covered in mildew one year. Lesson learned—keep the mildew-prone plants apart!
Another common mistake is planting mint near other perennials. Mint is highly invasive and can quickly take over a garden bed, choking out less vigorous plants. If you want to grow mint, it’s best to keep it confined to a pot where it can’t spread.
9. Embrace Experimentation
Gardening is as much about experimentation as it is about following rules. Every garden is different, and what works for one gardener might not work for another. The best way to learn what works in your own garden is to try new combinations, observe the results, and make adjustments as needed.
I keep a garden journal where I jot down notes about what I’ve planted and how things are going. It’s helped me identify which plant combinations work well together and which ones don’t. Plus, it’s a great way to keep track of the progress of my garden over the years.
So don’t be afraid to try new pairings and move things around. Gardening is a living experiment, and every season brings new opportunities to learn and grow.
Final Thoughts
Companion planting with perennials is a brilliant way to create a healthier, more resilient garden that requires less maintenance. By choosing the right plant combinations, you can boost growth, attract beneficial insects, and create a garden that practically takes care of itself.
Whether you’re working with a large country garden or a small urban plot, companion planting can help you make the most of your space and create a garden that you’ll love for years to come. So grab your trowel, get planting, and see how these perfect plant partnerships can transform your garden into a thriving, vibrant oasis.
