Best Perennial Companions for Dahlias That Bloom Late Into the Season

Dahlias, blooming till late in the season, with their warm colors and many shapes, from cactus to single, ball and even water lily or orchid, offer great blossoms for borders and even indoors, as cut flowers. And you can grow them on their own, but they do look better with some companion plants, as a flowery backdrop to their showy display, or even to match it, if you choose the right varieties!

And if you want your borders and containers to have a natural look, you should always pick some good companion perennials for your dahlias, whether you want them to be the absolute star of your summer and fall garden, or you want them to share the leading role.

So, looking for the best perennials to grow as companion plants to your favorite dahlias? They are all waiting for you, just here!

18 Ideal Perennials To Grow As Companions To Your Favorite Dahlias

So, out of the thousands of perennials you can grow in your garden, some varieties excel as companions for your beloved dahlias, and here they are!

• African lily
• Peruvian lily
• ‘Lime Green’ flowering tobacco
• Golden marguerite
• Coneflower
• Torch lily
• Daylily
• Culver’s root
• Black eyed Susan
• Sword lily
• Beardtongue
• Guernsey lily
• Montbretia
• Snapdragon
• Aster
• Globe thistle
• Cranesbill
• Sneezeweed

Of course, you can experiment with other perennials (and annuals) if you wish, but you need to do it wisely. Thus, before we meet the very best, let’s see what a perennial need to be a good companion for your dahlias, and also how to use them to have a great effect in your garden.

How To Choose The Ideal Companion Plant For Your Dahlias

First of all, not all perennials will make good companion plants for your favorite dahlias… You need to choose them carefully, so you match both their needs, and you get the best flowering spectacle in your garden!

Good Companion Perennials for Your Dahlias: Growing Conditions

Of course, you need to match the growing conditions of your dahlias and the perennials you choose as their companions. For example, while you can choose a drought tolerant variety, you cannot choose a shade loving one.

So, good companion plants for dahlias will need to tolerate full Sun, but they will also need to grow well in the same soil, be it loam, clay or sand based, but not chalk. They can be drought tolerant, but they also need to live well in medium humid soil. No succulents then!

Good Companion Perennials for Your Dahlias: A Matter of Looks

Then again, you want your dahlias to have companion plants that look good next to them. And this involves a few factors.

• They need to bloom at roughly the same time; no point in growing daffodils, or other spring flowering perennials!
• They need to be in scale; choose varieties that are the same, a bit bigger or smaller in size, but not colossal varieties, nor really tiny ones, as the former would overshadow your dahlias, the latter would disappear. You can pick shorter plants, as backdrop, but still, they would need to emerge among the dense foliage of dahlias…
• Bloom size matters; if you choose varieties with small flowers, they could be a good backdrop, but maybe you need very floriferous plants, or the little blossoms would disappear.
• A matter of colors; and this is mostly up to you. But if you want a harmonic effect, warm colors will be best. White could set off red, orange, purple or yellow dahlias, but blue would give you a strong and vibrant contrast instead.

How to Grow and Use Companion Plants to Dahlias

But how can we use companion plants with dahlias? The answer really depends on the effect you want to achieve. Our tuberous perennial has showy blossoms, in warm colors. So, playing with the size, shape and color of the perennials you want to grow with it you can…

• Have a discreet but colorful backdrop for your dahlias. You can do this by choosing varieties with smaller blossoms, but with colors in the warm range, white or pastel.
• Have a co-protagonist, with perennials with very showy flowers, big and bold, a different shape (so they stand out) and warm colors (for a matching effect) or cold (for a dramatic effect).
• Have a powerful backdrop, growing very floriferous perennials with warm or neutral colors, to enhance the effect of the blooms of your dahlias.
• Have a contrasting backdrop, choosing varieties with a cold color range.

And now you know how to choose the best perennials as companions to your favorite dahlias, you can read on and pick the varieties that best suit your needs, your taste, a d the effect you want to achieve!

The Best Perennial Varieties To Grow As Companions To Your Favorite Dahlias

And here they are, the very best varieties of perennials that you can grow as worthy companions to your dahlias in your borders or in containers.

1: African Lily (Agapanthus spp.)

African lily, or Agapanthus, is just perfect as a companion to your favorite dahlias! It blossoms in mid and late summer, and some into early fall; it has a similar hardiness, so you can take the bulbs and tubers out of the soil together, it can be tall, but, above all, it has massive flowers! Well, the many trumpet shaped blossoms are not that large in themselves, but the usually spherical inflorescences can reach 10 inches across (25 cm)!

So, they will not fall into the background, but they will share the stage with them! The choice of varieties and cultivars is quite wide, and you could choose white if you don’t want to have a strong contrast (like Agaphanthusorientalis ‘Albus’ with massive snow colored blossoms), or you could go for blue (‘Northern Star’) or violet (‘Purple Cloud’) if you want some vibrant but cool shades to balance the warm palette of dahlias. The long, fleshy and strap like foliage at the base will also give you a texture change from the broad and divided, pinnate leaves, often dark of our protagonist.

African lilies are easy to grow and they can range quite a lot in height, so you can have them at the base of your dahlias but also towering above them with their massive blossoms. They will also attract lots of butterflies, bees and even hummingbirds to your summer (and early fall) garden!

• Hardiness: USDA zones 7 to 11.
• Light exposure: full Sun and partial shade.
• Flowering season: mid to late summer, some varieties also early fall.
• Size: 18 inches to 6 feet tall (45 cm to 1.8 meters) and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:fertile and organically rich, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is salt tolerant.

2: Peruvian Lily (Alstroemeria spp.)

If you want to go fully safe, and grow a perennial that will always give you an outstanding effect with your dahlias in your borders, choose Peruvian lily! Its exotic looking, almost orchid like, trumpet shaped flowers are about 2 inches across (5.0 cm), not huge, but they come in such a great profusion that they will create a blanket of colors among the usually bigger blossoms of our tuberous beauties!

And they will bloom very generously all the way from early summer into fall! Loved by butterflies and bees, they attract them with their hot and vibrant palette, and with the very decorative dark purplish, or red streaks that lead them to the sweet nectar they hide… The choice of shades is large, with yellows, pinks, oranges and reds, and some delicate notes, like salmon and coral… The lance shaped leaves that climb up onto the stems will add texture and mix in perfectly well with your dahlia’sfoliage.

Despite its very exotic look. Peruvian lily, is another tuberous perennial, so, very easy to grow, and suitable to the hardiness of dahlias. Their match seems to be made in heaven, and these tow plants will work together for a really intense and long lasting floral display.

• Hardiness: USDA zones 7 to 10.
• Light exposure:full Sun and partial shade.
• Flowering season:early summer to fall.
• Size:1 to 3 feet tall (30 to 90 cm) and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:fertile and organically rich, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline.

3: ‘Lime Green’ Flowering Tobacco (Nicotiana alata ‘Lime Green’)

For a light and fresh backdrop to your favorite dahlias, I would suggest growing ‘Lime Green’ flowering tobacco in your borders. This perennial is a close relative of the plants used in cigarettes and cigars, but it has really great garden merit, and a nice fragrance, especially in the evening.

It will flower all the way from early summer to fall, together with our tuberous queen, producing lots of trumpet shaped blossoms that open into five pointed stars, which will attract butterflies, bees, pollinators of all sorts and even hummingbirds to your garden. And its long lasting bloom will offer you a lovely and rejuvenating lime color, closer to green than yellow, perfect to set off the hot palette of our protagonist!

This floral display will rise up from a basal rosette of very decorative, lance shaped leaves, in a greenish to bluish shade, adding even more coolness to the ensemble. And you will also have a champion with you, as it has won the prestigious Award of Garden Merit by the Royal Horticultural Society!

‘Lime Green’ flowering tobacco is a tender perennial, hardy only to USDA zones 10 to 11, but it is fast growing and it will blossom profusely in its first year among your dahlias, so, you can keep it as an annual if you live in anon tropical or subtropical climate.

• Hardiness: USDA zones 10 to 11 (or USDA zones 3 to 11 as an annual).
• Light exposure: full Sun and partial shade.
• Flowering season:early summer to fall.
• Size:1 to 3 feet tall (30 to 90 cm) and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:fertile and organically rich, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline.

4: Golden Marguerite (Anthemis tinctoria)

If you want to add extra radiance and energy to your borders, where you grow your dahlias, you should definitely have a look at golden marguerite. This hardy perennial will also suit the basic shape of our tuberous protagonist’s blossoms, because they are daisy like, with long and narrow ray petals, and then a perfectly round, geometrically exact dome in the center, quite sculptural and reminiscent of cone flowers, or even tennis balls.

And the color of these s can vary along the yellow range, from almost cream, to canary and finally super bright and vibrant golden yellow! Very attractive to many pollinators like butterflies, it will bloom very profusely from early to late summer and, in good conditions, even into fall, with a rich floral display that covers all the top of the plant! But the foliage will add even more to your composition,because it is aromatic, and very finely cut, fern like, and with an exquisite texture! And it is evergreen as well…

Easy to grow and very adaptable, golden marguerite really matches the warm color range and flower shape of dahlias, though its flowers are smaller. It is really excellent to mix with varieties in red or purple, and add a sea of yellow blooms and fine foliage to their spectacle!

• Hardiness: USDA zones 3 to 8.
• Light exposure: full Sun.
• Flowering season: early to late summer, sometimes into fall.
• Size:2 to 3 feet tall and in spread (60 to 90 cm).
• Soil and water requirements:average fertile, well drained and medium humid to dry loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought and salt tolerant.

5: Coneflower (Echinacea purpurea)

Mixing coneflowers with dahlias is yet another assured success! Like with golden marguerite, its blossoms have the same basic structure as our tuberous perennial, that of a daisy like flowers, to which, of course, it adds the 3D central disk, which become, in fact, a cone… What is more, it will give you a very intense, long lasting and really generous floral display at the same time, from early summer to fall, even up to the first frost!

And then, of course, we the palettes of these two plants really match, with purples, pinks, reds, yellows and oranges all available and in many combinations thanks to the many varieties of Echinacea available to gardeners nowadays. For example, you could choose ‘Flame Thrower’, with deep tangerine ray petals that warm up to scarlet towards the center, and a really showy cone in deep red, or the frilly and showy ‘Secret Passion’, with pink rays and a large, cerise and globular dome in the middle, resembling anemones… The broad lance shaped leaves at the base and growing up the stems will also add texture to your borders, and then, as you know, you can use it for medicinal purposes, as well as to attract pollinators to your garden.

Yet another easy to grow, tough and very adaptable perennial, coneflowers can fill in gaps between dahlias in your borders, or it can provide a colorful backdrop with bigger varieties of our protagonist. And it will give you long lasting cut flowers as well…

• Hardiness: USDA zones 4 to 9.
• Light exposure: full Sun.
• Flowering season: early summer to fall, even late fall.
• Size: 2 to 3 feet tall and in spread (60 to 90 cm).
• Soil and water requirements:average fertile, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

6: Torch Lily (Kniphofia spp.)

Also known as red hot poker, torch lily will give you a harmonious color combination with dahlias, but a different shape! This allows you to have contrasting blossoms that still work well together… As its name suggests, this perennial has a warm palette, with shades of yellow, orange and red, but also pinks, white and green.

And its floral display will last all the way from late spring to early fall, as it grows long stems with loads of tubular flowers, that start opening at the bottom and then move up and up till the tip. The effect is that of a dense plume, or a flame, rising up in your garden and in your borders, attracting lots of pollinators and hummingbirds as well!

Some varieties have more conical inflorescences, like ‘Bee’s Lemon’ (lemon yellow and then hay green higher up), or ‘Joker’s Wild’ (coral), but you can also choose Kniphofia rooperi, with shorter and plumper, top heavy clusters. The lush and semi glossy, grass blade leaves at the base form a really dense and decorative clump too, filling in the gaps left by the foliage of our tuberous queen.

Growing torch lily with your dahlias allows you to give an interesting structure to your garden, while keeping within a matching color range. It is also a sturdy very generous and tuberous perennial, which can spread and which you can leave in situ in winter as well, being cold hardy as well!

• Hardiness: USDA zones 5 to 9.
• Light exposure:full Sun.
• Flowering season:late spring to early fall.
• Size:1 to 6 feet tall (30 cm to 1.8 meters), depending on the variety, and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:fertile and humus rich, well drained and medium humid humid to dry loam, clay or sand based soil with pH from mildly acidic to neutral. It is drought tolerant.

7: Daylily (Hemerocallis spp.)

And now, one of the world’s favorite perennials ever: daylily! Of course, you can grow it as a companion to your favorite dahlias, and this will definitely solve a lot of problems for you! As you know, it is a super easy to grow plant, and it is so generous with its lily like blossoms that no gardener has ever regretted planting it!

With more than 35,000 (!!!) varieties and blooms that can reach 8 inches across (20 cm!), you will have a massive floral display that can last from late spring to fall, if you pick early, late and rebloomingcultivars! Each flower, as you know, last for only one day (hence the name) but new buds will open continuously and so generously that you won’t notice it – even if you don’t deadhead them!

Then again, you have itsimpressive color range to play with… Virtually all shades from white to yellows, oranges, pinks, reds, purples and even green, in all combinations and tonalities, the world’s your oyster with Hemerocallis! Many are fragrant as well, while all have a super lush set of glossy and fleshy strap like leaves that fill your borders and provide a twist to the foliage of our tuberous protagonist.

Growing daylilies is the easiest job in the world. Just plant them and they will basically do all the rest. As companions to dahlias, they will really offer you a safe and playful choice, with blooms that match in color and size, but differ significantly in shape!

• Hardiness: USDA zones 3 to 9.
• Light exposure: full Sun and partial shade.
• Flowering season: late spring to early fall (depending on the variety).
• Size: 1 to 5 feet tall (30 cm to 1.5 meters), depending on the variety, and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:average fertile, well drained and medium humid to dry loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

8: Culver’s Root (Veronicastrum virginicum)

Native to North America, culver’s root will add a fluffy touch to your borders and a soft backdrop to your dahlias. In fact, our tuberous perennials will open their large and colorful blossoms in the clouds, and that’s the effect you will get.

Yes, because Veronicastrum virginicum will bloom at the same time, from mid summer to fall, but with long and branched spikes packed with lots of tiny, white, pink, blue or purple tiny little and soft looking flowers, like snowflakes, or candy floss!

These clusters will look up to the sky, rising like smoke or mist, or fog in your borders, and they will attract many pollinators, like butterflies and bees, adding a vertical accent to your garden. On t of this, very decorative long, pointed and lanceolate leaves will add a touch of mid to dark green, with fine texture and a light leafy presence.

Incredibly tough and very cold hardy, culver’s root can stay in your garden over winter, even if you need to shelter your dahlias’ tubers during the cold season. It will not compete with its companion on the stage, but rather give you a wooly backdrop for it to shine and show off all its beauty!

• Hardiness: USDA zones 3 to 9.
• Light exposure:full Sun.
• Flowering season:early summer to fall.
• Size:3 to 6 feet tall (90 cm to 1.8 meters) and 2 to 4 feet in spread (60 to 120 cm).
• Soil and water requirements:average fertile, well drained and medium humid to wet loam or clay based soil with pH from mildly acidic to neutral. It is wet soil tolerant.

9: Black Eyed Susan (Rudbeckia spp.)

Imagine seeing your dahlias open their showy blooms in a sea of big, daisy like and colorful flowers… Well, that’s what you will get if you grow any blackeyed Susan variety as a companion to our tuberous perennial. And in fact, they will blossom at the same time, from mid summer to early fall, with a very big, generous floral display!

Each head can be 2 to 4 inches across (5.0 to 15 cm), depending on the species or cultivar you choose, and they can be single or double. Of course, what they have in common is a central disk, cylindrical in shape but short, which is usually dark purple (“black”, though shades can vary from burgundy to eggplant), but sometimes also yellowish or brownish.

And then, you get the long and narrow ray petals that remind us of the Sun, and in many types of yellow, red, orange and purple, often with two tonalities on them… These will function as landing pads for butterflies, bees and other pollinators, while the lanceolate, broad and pointed, tough looking leaves in semi glossy green or bluish complete the show with elegance.

Super tough and easy to grow, very adaptable but also extremely generous with its long lasting floral display, black eyed Susan is a favorite in wild meadows and butterfly gardens, but also an excellent companion perennial for your dahlias, as a colorful flowery prairie as backdrop.

• Hardiness: USDA zones 3 or 4 to 10 (depending on the variety).
• Light exposure:full Sun and partial shade.
• Flowering season:mid summer to early fall.
• Size:2 to 4 feet tall (60 to 120 cm) and 1 to 3 feet in spread (30 to 60 cm); Rudbeckia maxima is 6 to 8 feet tall (1.8 to 2.4 meters) and 2 to 3 feet in spread (60 to 90 cm).
• Soil and water requirements:average fertile, well drained and medium humid to dry loam, clay or chalk based soil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

10: Sword Lily (Gladiolus spp.)

How could we forget one of the most popular late flowering bulbous (cormous) perennials ever, to accompany your favorite dahlias in their floral displays? Enter sword lily, then, though, maybe, it needs no introduction at all… Suffice to say that there are 250 to 300 species in this genus, and innumerable cultivars…

Loved as cut flowers, because they last so long in a vase (up to 20 days) and because they are so showy, with their amazing tall and upright spikes packed with sometimes very big blooms, that open from the bottom up, the famous Gladiolus will give you a contrast in terms of shape, with lily like blossoms and providing a vertical accent, or pull in your borders.

Then again, the two palettes really match, as you can pick a variety in white, or any shades of yellow, pink, orange, red and purple! But it also has violet and many bicolor options as well! The blade like and upright leaves will also give you a twist from the broad and pinnate foliage of our tuberous queen, piercing through the soft mound with green elegance.

What is more, sword lilies also roughly match the hardiness of dahlias, which will make it easy to uproot the tubers and corms together at the end of the season to overwinter them if you live in a temperate or cold region.

• Hardiness: USDA zones 8 to 10.
• Light exposure:full Sun.
• Flowering season:early to late summer, some varieties into early fall.
• Size:2 to 5 feet tall (60 cm to 1.5 meters) according to the variety, and 4 to 8 inches in spread (10 to 20 cm).
• Soil and water requirements:fertile and humus rich, well drained and medium humid loam, clay or chalk based soil with pH from mildly acidic to mildly alkaline.

11: Beardtongue (Penstemon spp.)

If you want to give a boost to your dahlias’ floral spectacle during its early display, you can grow any beardtongue variety as their companions, because they usually blossom in early and mid summer, but I have three exceptional cultivars for you, that will last into fall!

All will give you upright, thin and long stems that bear lovely bell shaped blossoms, very attractive to pollinators and also hummingbirds, and a nice contrast with dahlia’s blooms… And they will rise to about 3 feet tall, with fresh looking, green and lance shaped leaves that form a lush mound at the base.

But ‘Hidcote Pink’, of course, offers you elegant salmon to shell colored flowers, with darker stripes in their throat, while ‘Rich Ruby’, of course gives you a ruby to raspberry reddish purplish tonality. Alternatively, you could pick ‘George Home’, with a strong and vibrant magenta, which turns snow white in the center, giving you light, energy and contrast. Did I say that they are extraordinary? And indeed they are, because all three have won the most coveted gardening prize of all, the Award of Garden Merit by the Royal Horticultural Society!

Any of these three beardtongue varieties will enrich your dahlias’ performance by offering hot and vibrant colors, but a change in flower shape. They are all also very easy to grow and adaptable, and they also fill borders with their lush foliage all through the season!

• Hardiness: USDA zones 6 to 9.
• Light exposure: full Sun and partial shade.
• Flowering season:early summer to fall.
• Size:2 to 3 feet tall (60 to 90 cm) and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:average fertile, well drained and medium humid loam, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought and salt tolerant.

12: Guernsey Lily (Nerine sarniensisand Nerine bowdenii)

And now you can imagine the effect that trumpet shaped flowers that open to reveal long and pointed, curling petals will have next to your dahlias. And you can achieve this if you grow any Guernsey lily variety as their companion, but I would like to suggest two species in particular, both native to South Africa, and both blooming in late summer and early fall.

Nerine sarniseniswill give you umbels of really showy and vibrant scarlet red flowers, for a hot and spicy effect. On the other hand, winner of the Award of Garden Merit by the Royal Horticultural Society Nerine bowdeniiwill charm you with its bright and brilliant deep pink, and wavy edges, and light scent!

Each blossom is about 3.2 inches across (8.0 cm) and the whole spectacle will last for 4 to 6 weeks. The strap like and green leaves that come at the base are a final added bonus, but they won’t last much longer than the floral display.

I would suggest you grow any of these Guernsey lily varieties either mixed in with low dahlias, or at the front, because they are a bit shorter than most. These are late flowering bulbous perennials, and you can overwinter the bulbs and tubers of our two companions by uprooting them together.

• Hardiness: USDA zones 8 to 10.
• Light exposure: full Sun and partial shade.
• Flowering season: late summer and early fall.
• Size: 1 to 2 feet tall (30 to 60 cm) and 3 to 6 inches in spread (7.5 to 15 cm).
• Soil and water requirements:moderately fertile, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

13: Montbretia (Crocosmia spp.)

And now, let’s change the scenery… Imagine long spikes rising up above your dahlias and arching elegantly above them, packed with colorful curving and trumpet shaped flowers… This is what you will get if you choose montbretia as a companion plant to our tuberous perennial. In fact, in mid and late summer, it will grow tall spikes with flowers on the upper side only, that open from the bottom and moving to the tips by degrees, like flames sparking up in your garden!

And you can pick the variety too… The most popular is certainly ‘Lucifer’, with blooms that are dark yellow to orange at the base, and scarlet red in the upper part, and winner of the Award of Garden Merit by the Royal Horticultural Society, as is Crocosmia masoniorum, but with bright carrot blossoms, while ‘Limpopo’ offers you a blend of salmon pink and coral! All will also give you blade like and erect leaves at the base, similar to those of sword lilies’ and they will provide an eye catching vertical accent.

And when the blossoms of Crocosmia, or montbretia have faced away, you can simply cut off the long stems, and keep enjoying your dahlia’s blooms, which will keep coming till later in the season. But this burst of energetic flowers will remain in your memory…

• Hardiness: USDA zones 5 or 6 to 9 (depending on the variety).
• Light exposure: full Sun and partial shade.
• Flowering season:mid and late summer.
• Size:2 to 5 feet tall (60 to 150 cm), depending on the variety and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:fertile and organically rich to average, well drained and medium humid to dry loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought and salt tolerant.

14: Snapdragon (Antirrhium majus)

Grown as short lived perennials but also as annuals, snapdragons can be really colorful and floriferous companions to your dahlias. They will also blossom from late spring into fall, giving your garden and your borders a really long season, but their blossoms offer a contrast in shape with our tuberous beauty… Long and upright spikes will bear conical inflorescences, where each flower is snout shaped, opening up to big and rounded lips, and this makes them ideal feeding sources for butterflies as well as hummingbirds.

There are dwarf varieties, that grow to 6 inches tall (30 cm) as well as tall ones, reaching 3 feet from the ground (90 cm), and these may be better for our purpose. Sweetly fragrant, the blossoms come in a wide palette of warm shaded, some bright and strong, other delicate. So, you can get white, pink, rose, yellow, orange and red blooms, but also peach, salmon and bicolor in tonality! Climbing up on the stems are also the small but decorative lanceolate leaves, herbaceous in appearance and rich green in color…

Very easy to grow and manage, snapdragons will provide a wonderful and very long lasting backdrop for your dahlias; you could grow them to push their long clusters through the foliage of our tuberous perennial, or choose a smaller variety to have at the front, or to frame our protagonist.

• Hardiness: USDA zones 5 to 10.
• Light exposure: full Sun.
• Flowering season: late spring to fall.
• Size: 6 to 36 inches tall (15 to 90 cm), depending on the variety, and 6 to 10 inches in spread (15 to 25 cm).
• Soil and water requirements:average fertile, well drained and medium humid loam, clay, chalk or sand basedsoil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

15: Aster (Aster spp.)

Blooming late in the season, asters can become a wonderful backdrop for dahlias if you choose them as companions for our tuberous perennial… In fact, their daisy like blossoms are so floriferous that they literally form a blanket of long and thin petals, and usually golden central disks.

While the basic shape of the flowers is similar in the two plants, those of asters are much smaller, but dense, and they will not compete with your border’s protagonist, while setting it off with a massive floral display that can last from mid summer to frost!

Of course, you also have a pick of colors and sizes, with a palette that includes white, pink, rose, violet, purplish and blue, with many shades and tonalities available, including bright and vibrant or soft and delicate pastel… The texture of the foliage will also add to the ensemble, thanks to the many small, but long and narrow leaves that form a dense clump under this flowery coat, which consistently fills with pollinators like bees, butterflies and beetles…

Yet another easy to grow perennial to have as a companion to your favorite dahlia, aster is one of the best to reach the end of the flowering season, when your borders may start showing gaps, and they may need a few flowers to fill them in.

• Hardiness: USDA zones 5 to 8.
• Light exposure:full Sun, some varieties tolerate partial shade.
• Flowering season:mid summer to late fall, depending on the variety.
• Size:1 to 6 feet tall (30 cm to 1.8 meters) and 1 to 4 feet in spread (30 to 120 cm), depending on the variety.
• Soil and water requirements:average fertile, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline.

16: Globe Thistle (Echinops spp.)

As a companion to your favorite dahlias, globe thistle offers a playful contrast with shape and shade, which will last all through the months of summer, and, with some varieties, into the beginning of fall, all accompanied by the fluttering wings of butterflies and buzzing of bees!

In fact, it will produce long and sturdy, upright stems that can be silver or even bluish, on top of which, you will see spheres, yes, balls of color… These are the geometrically striking inflorescences, made up of many tiny and tubular little flowers. Look closely, and you will see long stamens protruding out, and that each little blossom opens to a very elegant star shape.

And then, you will also add a color that can be from soft pale sky (for example Echinopssphaerocephalus ‘Artic Glow’), to vibrant cobalt blue, almost electric (Echinopsbannaticus ‘Blue Glow’), violet bluish (Echinopsritro subsp. ruthenicus, winner of the Award of Garden Merit by the Royal Horticultural Society)to grayish silver (Echinopsbannaticus ‘Star Frost’). These glitter-ball like clusters can be 1 to 2.5 inches across (2.5 to 6.0 cm), and they come with the added bonus of finely cut, glossy and rich to dark green leaves.

Growing globe thistles as companions to your dahlias will add a party mood to your summer and fall borders. It is a daring, even bold choice, but this ill guarantee a playful and never boring effect.

• Hardiness: USDA zones 3 or 4 to 8, depending on the variety.
• Light exposure:full Sun and partial shade.
• Flowering season:early summer to fall, depending on the variety.
• Size:2 to 4 feet tall (60 to 120 cm) and 2 to 3 feet in spread (60 to 90 cm).
• Soil and water requirements:average fertile, well drained and medium humid to dry loam, clay or sand based soil with pH from mildly acidic to mildly alkaline. It is drought and rocky soil tolerant.

17: Cranesbill (Geranium spp.)

Of course, the marriage between two classic late flowering perennials is a match made in heaven! So, it goes without saying that cranesbills and dahlias are perfect gardening companions indeed. But, while our tuberous queen will give you big and showy blossoms, often in vibrant and deep tonalities, Geranium varieties will give your borders a backdrop of delicate looking, saucer shaped smaller flowers, with a fairly open floral display, reminiscent of the butterfly wings that will accompany it all the way from early summer to fall.

And, of course, you can pick from a very interesting palette, for example the rich magenta of ‘Ann Folkard’, or the luminous and intense blue violet of ‘Rozanne’. But you can also have snow coloredpetals with soft shell pink veins with ‘Kasmir White’, or the sky blue of ‘Orion’, or gentle mauve of ‘Mavis Simpson’. All, however, will offer you a lovely clump pf deeply cut, almost fern like rich green leaves, fresh looking and finely textured.

Growing cranesbills as companions to your favorite dahlias allows you to play with a gentle looking backdrop perennial with a color range that can match or contrast with that of ourtuberous queen, allowing you to vary and regulate the final effect.

• Hardiness: USDA zones 4 to 8.
• Light exposure:full Sun, partial shade and full shade.
• Flowering season:early summer to fall.
• Size:6 to 40 inches tall (15 to 100 cm) and 12 to 24 inches in spread (30 to 60 cm), depending on the variety.
• Soil and water requirements:average fertile, well drained and medium humid to dry loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is drought tolerant.

18: Sneezeweed (Helenium spp.)

Why not grow a perennial with a super sunny personality as a companion to your favorite dahlias? Then, sneezeweed, or Helenium is just perfect and the final effect is guaranteed. This plant, in fact, has a range of extremely warm colors, and it has large daisy like blossoms up to 3.2 inches wide (8.0 cm), and it is very floriferous indeed.

So, it will match the showy flowers of our tuberous queen of late season borders, but it will do it with a sea of fire and light, rather than with individual blooms, providing, at the same time, a luminous backdrop. With a central disk which is roughly dome shaped and it can be dark purple (“black”), deep violet, yellowish or reddish brownish, it will offer you ray petals that form a flat circle at first, but then they folddownward, making the flowers look like shuttlecocks.

The choice you have is along the yellow to red range, like with the bright golden ‘Zimblestern’, the sensuous warm and intense orange of ‘Shain’s Early Flowerer’, or the super scarlet of ‘Moerheim Beauty’, winner of the Award of Garden Merit by the Royal Horticultural Society.

And this is a prize that also ‘Feuersiegel’ has received, thanks to its bicolor contrast of saffron splattered with crimson dashes! All will attract hordes of bees, butterflies and other pollinators to your garden, and hummingbirds as well. And all come with herbaceous and fresh looking, lance shaped leaves in bright to rich green.

Sneezeweed is one of the best perennials to enhance the showy flowers of your favorite dahlias. Easy to grow and with massive blooms, it will create a sunny flowery stage for this amazing tuberous queen to shine!

• Hardiness: USDA zones 3 to 8.
• Light exposure: full Sun.
• Flowering season: early or mid summer to fall, depending on the variety.
• Size:3 to 5 feet tall (90 cm to 1.5 meters) and 1 to 2 feet in spread (30 to 60 cm).
• Soil and water requirements:average fertile to lean, well drained and medium humid loam, clay, chalk or sand based soil with pH from mildly acidic to mildly alkaline. It is heavy clay and wet soil tolerant.

Your Favorite Dahlias And Their Best Friends

So, you have just met the very best perennials to grow as companion plants to your dahlias, all are friends, but with different personality, and you have also learned how to combine them to have a wide range of successful effects. And now, it is up to you to choose the one that will give you the results you are looking for.