15 Perennial Plants You Can Plant This August

As I sit here, I am looking around my gardens thinking, “What do I have here that blooms in August?”. Well, the answer is usually “not much!”.  August is an odd month, with the heat turned up and the beginning of fall just around the corner. In many places around the country, the weather has cooled down a bit from the July heatwaves and the pressure of watering so much has started to taper off.

August isn’t usually a time that planting is recommended, but depending on where you live it is definitely possible. It’s a great time to hit the garden center sales, and load up on some perennials! It’s also not a bad time for planting in a perennial shade garden, which is typically shielded a bit from the heat.

So, are you ready to get planting in August? If you are looking for some late blooming perennial inspiration for your garden, read through this list below to find some new plants to try. Let’s dig in!

Planting in August

The climate in August is very different depending on where you live. No matter how warm it is, be sure to wait until any heat waves have passed before planting. Planting in the evening followed by a good deep watering will help keep any transplant shock in check.

If you like to fertilize when you plant, you will want to hold off. Add some compost instead to give your new plants a nutrient boost.

August is actually a great month for succession planting herbs and vegetables. So while it may not be the “perfect” month for planting new perennials, so don’t shy away from adding some of our favorites from the list below!

Bluebeard

Scientific Name: Caryopteris x clandonensis

• Plant Size: 2-5 feet depending on variety
• Sun Exposure: Full Sun
• Bloom Time: Summer
• Plant Zone: 5-9

This small shrub will bloom when there is not much else blooming in your gardens. Most varieties of bluebeard have narrow silver leaves and will be covered in bluish purple flowers from the middle of the summer, lasting well into the fall.

These small shrubs are easily added to your landscape as a hedge or border shrub. Deadhead the spent flowers to encourage a longer bloom period.

Butterfly Bush

Scientific Name: Buddleia davidii

• Plant Size: 3-12 feet
• Sun Exposure: Full Sun
• Bloom Time: SUmmer
• Plant Zone: 5-9

Butterfly bush is a pretty shrub with pointed green leaves, with spiky colorful flowers that really do attract a lot of butterflies. There are many varieties of this plant available in all different sizes.

Butterfly bush is resistant to heat and drought, making it a great late-season addition to your garden. You can also find butterfly bushes in a variety of colors although the most popular is their beautiful perennial purple blooms. This is a rapidly growing shrub and hard pruning in the springtime will encourage vigorous growth and lots of flowers!

Coral Bells

Scientific Name: Heuchera spp.

• Plant Size: 1-2 feet
• Sun Exposure: Full to partial sun
• Bloom Time: Summer
• Plant Zone: 4-9

With close to 100 varieties of coral bells in a wide variety of colors, this makes an excellent addition to any garden. I love to use coral bells in my fall containers and plant them in my garden before the frosts come.

Grown primarily for their foliage, these perennials make nice border plants and accent all of your flowering plants nicely. Tuck some of these plants into your hosta gardens for a change in texture and color.

Fountain Grass

Scientific Name: Pennisetum alopecuroides

• Plant Size: 2-3 feet
• Sun Exposure: Full sun
• Bloom Time: Late summer
• Plant Zone: 4-9

Adding ornamental grasses to your garden will provide you with year-round interest. Fountain grass has narrow elegant leaves that arch down to the ground creating a really pretty waterfall effect.

The flowers are small spikes that are gorgeous when left on the plant or when cut to add to arrangements. Plant fountain grasses on their own as a specimen plant or, my favorite, in a mass planting to get the optimal effect of the arching leaves.

Garden Mum

Scientific Name: Chrysanthemum sp.

• Plant Size: 1-3 feet, variety dependent
• Sun Exposure: Full Sun
• Bloom Time: Summer, Fall
• Plant Zone: 5-9

Why not make the classic garden mum a full-time resident in your garden? Garden mums are gorgeous when planted in your garden and are easy to take care of! These late bloomers do need a little help holding off on flowering.

Continually pinch the flowers back until July to create a bushy plant that will be full of buds. Of course, if you are planting garden mums in August you won’t need to worry about that. Mums aren’t known for their foliage so be sure to plant these perennials in an area of your garden that has other interests throughout the summer.

Once the flowers have passed, trim them back to within a few inches of the ground and cover them with hay or mulch to help keep them warm through the winter.

Hydrangea

Scientific Name: Hydrangea sp.

• Plant Size: 2-8 feet, species dependent
• Sun Exposure: Full sun to partial shade, species dependent
• Bloom Time: Late spring- Fall
• Plant Zone: 3-9

Planting hydrangeas in August might not provide you with beautiful flowers this year, however, it will set you up nicely for next year. These flowering shrubs have large flowers in the prettiest colors, but hydrangeas are famed for their blue blossoms.

If you are seeking blue flowers you will want a bigleaf hydrangea or Hydrangea macrophylla. Whichever species of hydrangea you choose, they are versatile plants and there is a hydrangea for every spot in your garden, even your containers.

Japanese Anemone

Scientific Name: Anemone hupehensis

• Plant Size: 2-4 feet, variety dependant
• Sun Exposure: Full sun- partial sun
• Bloom Time: Late summer- Fall
• Plant Zone: 4-8

Japanese anemones are pretty flowers that come in whites, pinks or purples. These perennials will spread by rhizomes once they have established themselves in your garden, so choose a location with that in mind.

Perhaps a big empty space that you are trying to tackle. Anemones are pretty planted in a border garden behind a lower growing perennial or maybe some annuals.

Maiden Grass

Scientific Name: Miscanthus sinensis

• Plant Size: 6-8 feet
• Sun Exposure: Full sun
• Bloom Time: Late Summer
• Plant Zone: 4-9

Maiden grass is a beautiful ornamental grass. This grass has fine leaves that are green with a silver tone to them. The flowers on this grass are graceful and long, but they are not the reason to grow this grass.

Plant this grass around a walkway, or a pool and enjoy the pretty waving foliage toward the end of the summer. The leaves will turn a bronze color after a frost and can be cut back in the fall or the spring. A very popular and dependable variety of maiden grass is ‘Adagio’.

Masterwort

Scientific Name: Astrantia major

• Plant Size: 1-2 feet
• Sun Exposure: Partial- full shade
• Bloom Time: Spring, Summer
• Plant Zone: 4-9

The flowers on masterwort, or pincushion, are very interesting. They are made up of florets that are backed by bracts that have the appearance of petals. This combination gives the flowers the appearance of fireworks or a pincushion.

Masterwort likes moist soil, so planting in the shade in August may require a little bit of extra watering, but if your shaded areas are damp this is a perfect low-maintenance plant for you. Cut these flowers for arrangements or enjoy them as a middle plant throughout your shade gardens.

Montauk Daisy

Scientific Name: Nipponanthemum nipponicum

• Plant Size:
• Sun Exposure: Full sun
• Bloom Time: Midsummer- Frost
• Plant Zone: 5-9

This is the perfect plant to fill that late summer/ fall bloom void in your garden. The montauk daisy is from the same family as more traditional daisies. It’s covered in daisy-like flowers. This plant loves the sun and should be pinched back around the 4th of July to avoid any flopping.

These flowers will last until the frost and the plant will die back until next year. Montauk daisies have naturalized themselves on Long Island, New York- hence their name. They are excellent options for other coastal locations as well!

New England Aster

Scientific Name: Aster novae-angliae

• Plant Size: 1-3 feet
• Sun Exposure: Full or Partial sun
• Bloom Time: Late Summer – Early Fall
• Plant Zone: 4-8

Asters are popular autumnal companions to the chrysanthemum, and in many areas where chrysanthemums are not hardy, Asters make are a great replacement! This pretty herbaceous perennial comes in shades of purple, pink, and white.

Asters will bloom until the frost, and even longer in frost free areas. These perennials attract pollinators of all kinds. Plant sporadically throughout your perennial gardens, or in a large mass for a big splash of color. A notable and dependable variety is ‘Purple Dome.

Perennial Hibiscus

Scientific Name: Hibiscus sp.

• Plant Size: 3-4 feet
• Sun Exposure: Full to Partial Sun
• Bloom Time: Mid- Late Summer
• Plant Zone: 4-9

If you are looking for a plant with showy flowers that is also low maintenance, perennial hibiscus (or mallow) just may be the plant for you. The foliage on these plants is large and ornate, giving a very tropical feel to your gardens.

The foliage is pretty enough on its own, but when the flowers arrive later in the summer your garden will be breathtaking. Perennial hibiscus comes in a variety of colors from white to red with combinations of every color in between. In the spring cut back branches to about knee high, and get ready for the show to begin.

Russian Sage

Scientific name: Perovskia atriplicifolia

• Plant Size: 2-3 feet
• Sun Exposure: Full sun
• Bloom Time: Summer
• Plant Zone: 4-9

Russian sage has always reminded me of taller catmint. Russian sage has silver foliage with spiky purple flowers. This perennial is a drought-tolerant plant and will bloom from summer through the fall.

Plant Russian sage in the sun to make sure that it is nice and compact. I love Russian sage when it is planted as a border however, it is really pretty planted throughout your perennial beds as well.

Sedum ‘Pure Joy’

Scientific Name: Sedum hybrid

• Plant Size: 1 foot
• Sun Exposure: Full Sun
• Bloom Time: Late summer- Early Fall
• Plant Zone: 3-9

We all know and love sedum, especially the famed ‘Autumn Joy’. This variety, ‘Pure Joy’ is a compact ground cover that is equally as dependable and just as beautiful. This sedum can be used in rock gardens or even in containers.

Come the late summer this succulent perennial will be covered in light pink flowers that will last until the frost. Because this plant is drought and heat tolerant it’s a great late summer addition that you won’t have to babysit.

Turtlehead

Scientific Name: Chelone obliqua

• Plant Size: 2-3 feet
• Sun Exposure: Full- Partial Sun
• Bloom Time: Summer- Fall
• Plant Zone: 5-9

I love this plant for a partially shaded garden. The foliage on turtlehead plants is deep green and glossy, the stems are straight making this a great plant for mass planting. Its flowers are reminiscent of snapdragons and are usually in the white or pink family.

These flowers will stay in bloom for about a month, taking you right into the fall. Turtlehead likes moist soil, so don’t forget to keep these plants watered.