Pairing Midsummer Perennials with Annual Plants

Does your perennial bed cry out for color during that stretch of summer between Independence Day and Labor Day? Then plant some annuals. They flourish in hot weather, high humidity, and even drought. Plus, its easy to add annuals right where you need a punch of color. And if you don’t like the combinations you create, it’s easy enough to switch things up next year.

Perennials to be matched

We’ve matched some commonly grown midsummer perennials with annual plants whose color, height, or structure look good together.

1. Black-eyed Susan (Rudbeckia fulgida)

“Bright Lights” cosmos, globe amaranth, tall cigar plant, and salvias all have colors and shapes that play well off those challenging yellow-orange petals with black centers.

2. Catmint (Nepeta)

Unless it’s cut back in late spring, catmint goes to ground—that is, it flops. Let it recline on a chartreuse sweet potato vine (used as a groundcover). Also try “Profusion White” zinnia or annual black-eyed Susan. Cardoon echos the catmint’s silvery foliage, but contrasts in size and shape.

3. Coneflower (Echinacea)

These look stiff and brittle to me, so I surround them with plants that look like they’re giving them a hug: pincushion flower, lantanas, tropical smoketree.

4. Coreopsis

Most coreopsis, be they bigleaf or threadleaf, have yellow or gold flowers, so anything that flowers in blue or purple looks good, including angelonia or salvias. Cigar plant flowers in orange and yellow-pink, so it harmonizes and contrasts at the same time.

5. Daylilies (Hemerocallis)

The straplike foliage contrasts well with copperleaf, dragon wing begonia, and anything else that grows up instead of down.

6. Lilies (Lilium)

Upright growers with trumpet-shaped flowers that emerge along the top of the stalk. Cover their spindly stems with full foliage: tropical smoketree, flowering tobacco, taro, copperleaf.

7. Rose campion (Lychnis)

Soften the screaming magenta flowers of rose campion with spider flower, “Ace of Spades” pincushion flower, or beets. (Yes, beets. ‘Bull’s Blood’ and “Ruby Queen” have terrific red leaves.)

8. Russian sage (Perovskia).

Sprawling, weedy-looking Russian sage works alongside any daisylike annual, hyacinth bean vine, sweet potato vine, or annual black-eyed Susan.

9. Salvias

Upright, spiky-growing perennial salvias look good next to anything with mass, including cardoon, spider flower, cosmos, and annual black-eyed Susan. Try creeping zinnia in front as a groundcover.

10. Shasta daisies (Leucanthemum)

Anything looks good next to them, even another daisy-flowered plant, as long as the flowers are different sizes. Go with spiky, broad, or straplike plants, including angelonia, lion’s ear, lantanas, and salvias.

11. Yarrows (Achillea)

Upright-growing yarrow’s flat-topped flowers are its fullest part, so pair it with spiky plants like New Zealand flax. Annual black-eyed Susan, as well as castor bean (which comes into its own as the yarrow’s flowers fade), will also complement yarrow’s form.

The best annuals for the job

If you’ve got a design problem in your perennial border, there is probably an annual that can provide a short term solution. Dozens of species of annuals make great planting companions with summer perennials. Some work better than others, depending on your design needs, climate or soil conditions.

The Big

• Cardoon (Cynara cardunculus)
• Castor bean (Ricinus communis)
• Lion’s ear (Leonotis leonurus)
• Taro (Colocasia esculenta)

The Bold

• Copperleaf (Acalypha wilkesiana)
• Dragon wing begonia (Begonia X hybrida)
• New Zealand flax (Phormium tenax)

The Beautiful

• Angelonia, esp. “Alba”, “Deep Plum”
• Cosmos, esp. “Bright Lights”
• “New Gold” Lantana
• Pincushion flower (Scabiosa spp.), esp. “Ace of Spades”
• Spider flower (Cleome hassleriana), esp. “Sparkler Bush” and “Violet Queen”

Ground Huggers

• Creeping zinnia (Sanvitalia procumbens)
• Sweet potato vine (Ipomoea batatas)
• Zinnia “Profusion” series

Hot Colors

• Annual black-eyed Susan (Rudbeckia hirta)
• Bat-faced Cuphea (Cuphea llavea)
• Cosmos, esp. “Bright Lights”
• Tall cigar plant (Cuphea micropetala)

Cool Colors

• Angelonia, esp. “Alba”, “Deep Plum”
• Flowering tobacco (Nicotiana spp.)
• Pincushion flower (Scabiosa spp.), esp. “Ace of Spades”
• Salvias
• Tall verbena (Verbena bonariensis)

Happy in Humidity

• Bat-faced Cuphea (Cuphea llavea)
• Globe amaranth (Gomphrena spp.)
• Lantanas
• Salvias
• Tall cigar plant (Cuphea micropetala)
• Taro (Colocasia esculenta)

Desire It Dry

• Cardoon (Cynara cardunculus)
• New Zealand flax (Phormium tenax)

The Sure Things

• Creeping zinnia (Sanvitalia procumbens)
• Tall verbena (Verbena bonariensis)
• Zinnia “Profusion” series

Vines

• Hyacinth bean vine (Lablab purpureus)
• Sweet potato vine (Ipomoea batatas)

Light and Airy

• Cosmos
• Pincushion flower (Scabiosa spp.)
• Tall verbena (Verbena bonariensis)