15 Fall-Blooming Flowers to Plant in August
August is one of the hottest months of the year in most places, so it can be difficult to go out and enjoy the garden. But those crisp, cool days of autumn are right around the corner, perfect for alfresco dining. Join gardening expert Melissa Strauss in planting some beautiful, fall-blooming flowers this August!
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By the time August rolls around, most of the summer bloomers are winding down and feeling the heat. Very soon, autumn will be upon us, and once again, we will look toward preparing the garden for spring. But, let’s not get ahead of ourselves. There are still some lovely fall-blooming flowers you can plant in August. These flowers will keep your garden blooming until frosts.
If you want to plant seeds in August, there are a couple of considerations to make. First, is your growing season long enough that your plants will mature and bloom in time? You don’t want to plant right up to that first expected frost date or risk all the effort to miss the bloom.
The other is the seed-to-bloom time for the individual plants. If you want to plant seeds in August, make sure to choose plants that have a short seed-to-bloom period. Planting nursery starts takes some of the guesswork out of the fall garden.
You can go to the local nursery and purchase plants that are in bloom, or nearing their bloom time. It’s a good idea to choose plants that can not only tolerate the potential heat of August and even September. Your chosen plants should also continue to bloom in cooler weather.
Here are some of the best fall-blooming flowers to plant in August. Most of these will flower right up to the first frost, some are lightly frost-tolerant. Let’s get prepping for that beautiful fall garden.
Zinnias
- Botanical Name: Zinnia elegans
- Sun Needs: Full sun
- Height: up to 3’
- Zones: 2-11
- Seed to Flower: 60-70 days
Zinnias are always at the top of my list any time we are talking about plants that bloom in a hurry. I plant zinnia seeds many times throughout the year, and I never get tired of seeing their cheerful faces. It only takes about two months to have these blooming from seeds.
That means if you get them in the ground in August, you’ll have zinnias from September until your first frost. You can plant zinnia seeds directly in the garden, and they have a great germination rate.
Plant two or three seeds every foot, and then thin them out to the strongest seedling when they’re about two inches tall. If you water before you thin your seedlings and take care not to damage their roots, they transplant well. Stick your extras anywhere in the garden where you want a bit of color.
French Marigolds
- Botanical Name: Tagetes patula
- Sun Needs: Full sun to partial shade
- Height: 6”-12″
- Zones: 2-11
- Seed to Flower: 50-60 days
French marigolds in autumn? Oui, sil vous plait! Marigolds come in different sizes, and naturally, the taller ones take longer to bloom. Petite French marigolds are fast growers that bloom in about two months. It’s easy to find nursery starts most times of the year. So this is one that you can plant from seeds or starts in August and have blooms well into the fall months.
Marigolds will suffer damage from frost, but they should be good until temperatures drop consistently below 40°F (4°C). Plant these with your fall veggies to help repel nuisance insects. Many insects don’t like the smell of the flowers. Marigolds self-seed, but not well. You can collect their dried seed heads in late fall and hold onto them for the spring. They are fast growers and easy to germinate.
Cosmos
- Botanical Name: Cosmos spp.
- Sun Needs: Full sun
- Height: up to 6’
- Zones: 2-11
- Seed to Flower: 50-60 days
Cosmos are another great, fast-growing annual that you can plant in August. You’ll have plenty of fern-like foliage and sweet little blooms by October. Bees adore these flowers, so planting them contributes an excellent fall food source to the garden. Since flowers become scarce in the fall, the pollinators are certain to appreciate these blooms.
These plants are not picky about soil as long as the drainage is good. They prefer soil that isn’t too nutrient-dense. Too much nitrogen can cause them to grow tall and become floppy. They are surprisingly drought-tolerant and don’t mind hot weather. They aren’t the biggest fans of cold weather, but they will continue to bloom until a frost.
Calendula
- Botanical Name: Calendula officinalis
- Sun Needs: Full sun
- Height: 1′-2′
- Zones: 2-11
- Seed to Flower: 30-50 days
I grow calendula year-round, although they aren’t fans of hot weather and need some shade in summer. They will flourish in the fall, so plant them in August to get a head start on these flowers. Calendula is a fast bloomer. Perhaps one of the fastest blooming plants I’ve grown. In as few as 30 days from germination, you can start seeing flower buds open.
You can directly sow these seeds in the garden. They will need moisture while they germinate but are relatively drought-tolerant once established. Rich soil will help your plants grow faster and larger and produce more blooms.
The blooms look like daisies in shades of orange, yellow, red, white, and pink. These plants will tolerate a light frost but not a hard freeze. They can bloom through the winter in warm climates.
Snapdragons
- Botanical Name: Antirrhinum majus
- Sun Needs: Full sun
- Height: 6”-3’
- Zones: 7-10
- Seed to Flower: 60-80 days
Snapdragons thrive in cool fall weather and will even survive a light freeze. Temperatures down to 25°F (-7°C) are fine for these plants. Here in North Florida, I grow them all year, though they do languish a bit in the summer heat. The fluffy flower heads are stunning in the garden and make excellent cut flowers.
Choose a smaller variety in cooler climates, as they will mature and flower faster. In warm climates, the sky is the limit. They may get a slow start if August is hot, though, so start these seeds indoors if you are still contending with summer heat. Snapdragons prefer full sun, but in warm climates, afternoon shade is better.
From Nursery Starts
These ten plants all flower in fall weather. They take too long to grow from seeds, but you should be able to find starts at most local nurseries.
Petunia
- Botanical Name: Petunia
- Sun Needs: Full sun
- Height: 6”-2′
- Zones: 2-11
Petunias take a bit too long to bloom from seed unless you get them started in the spring. However, you’re sure to find plenty of these pretty flowers at your local nursery as fall is on the horizon.
Petunias are sensitive to cold, so in cooler climates, they aren’t likely to make it to Thanksgiving. In warm climates, they should stick around for a while. Petunias make great container plants and mix well with other fall-blooming flowers.
These flowers come in a wide range of colors, both warm and cool tones. My personal favorite for the fall garden is ‘Black Cat.’ This petunia is the deepest purple you can imagine. It’s so dark that it appears black, and the petals are velvety soft.
These are amazing around Halloween, and they look wonderful mixed in with pumpkins and mums. Give your petunias plenty of water to keep them perky, and deadhead them diligently for maximum blooming.
Tickseed
- Botanical Name: Coreopsis spp.
- Sun Needs: Full sun
- Height: 6”-4’
- Zones: 4-9
Tickseed is a great little plant that brings a ton of color to the garden. These cheery flowers come in warm shades, and pollinators love them. The best part is they are perennial in Zones 4-9.
Even though you’ll want to cut them back after a frost, they will return in early spring. They will bloom right up until that first frost date, so you can enjoy the bounty of blooms for a long time. These plants grow easily from seeds, but they don’t always bloom in their first year. Planting them from nursery starts will ensure a strong first season.
They reseed if you leave flowers intact. However, they will bloom much better if you deadhead the spent blooms. This is a bit high maintenance because the flowers are bountiful and have slender stems that grow in large groups.
Chrysanthemum
- Botanical Name: Chrysanthemum spp.
- Sun Needs: Full sun to partial shade
- Height: 1’-4’
- Zones: 3-9
Chrysanthemums are the quintessential fall flower. Once August and September roll around, you can’t go anywhere without seeing these pretty plants. There are several types of this plant with different flowering habits. Some are small and shrubby, while others have tall stems and make wonderful cut flowers.
These flowering perennials make wonderful front porch decorations. Just make sure you put them in the ground before winter rolls in.
Don’t overwater your mums, as they are susceptible to powdery mildew. Their dense foliage needs to stay dry whenever possible. Avoid crowding them so they get proper air circulation.
African Daisy
- Botanical Name: Osteospermum spp.
- Sun Needs: Full sun
- Height: 1’-3’
- Zones: 10-11
African daisies are an underrated plant, possibly because of their small perennial range. In Zones 10-11, these will come back in the spring. Elsewhere, they are beautiful annual plants that bloom in spring, slow down in summer, and resume flowering in the fall. Planting these toward the end of summer will give them plenty of time to settle in before temperatures go down.
Keep the soil moist while these plants establish roots. Once they settle in, they become drought tolerant. Fertilize them monthly. They are heavy feeders.
A bloom-boosting fertilizer with high phosphorus will keep these plants flowering until the first frost. Pinch your plant to make it branch and flower more. Make sure to deadhead the spent blooms.
Salvia
- Botanical Name: Salvia spp.
- Sun Needs: Full sun to partial shade
- Height: up to 4’
- Zones: 5-10
Salvia is a herbaceous perennial that provides color in the garden, and nectar for pollinators, for up to three seasons. If you don’t already have salvia in your garden, pop some in the ground in August.
Keep it moist for a few weeks to let it set down roots. Once established this plant is drought tolerant and sturdy. It spreads by rhizomes and can be aggressive, so it works well as a container plant.
Salvia is not picky about soil. It grows and blooms best in full sun, but partial shade is fine in warmer climates. Don’t worry about fertilizing this plant, it is efficient with nutrients. Acidic soil is best for nutrient uptake, but it’s not vital to the life of the plant.
Coneflower
- Botanical Name: Echinacea spp.
- Sun Needs: Full sun
- Height: 2’-4’
- Zones: 3-9
Coneflowers are very adaptable plants that flower all the way up to the first frost in Zones 3-9. They are also perennials that return each year, providing food for pollinators.
If you leave the seed heads attached, they will draw overwintering birds to your yard. The blooms are striking with large, spiky, conelike centers and ray petals that fall backward away from the center.
These plants are not aggressive, but they will self-seed. They look gorgeous in a mass planting, so allowing them to spread some is worthwhile. Deadheading throughout the season will bring more blooms. Leave the foliage over the winter for the birds and cut it to the ground before new growth appears in spring.
Strawflower
- Botanical Name: Xerochrysum bracteatum
- Sun Needs: Full sun to partial shade
- Height: 6”-60”
- Zones: 8-10
If you appreciate a flower that dries nicely, strawflowers are simply wonderful. They are short-lived perennials in warm climates and annuals elsewhere.
They are not difficult to start from seed, they usually have a good germination rate. However, they take several months to flower. If you’re starting in August, better to start with nursery starts for blooms in autumn.
Strawflowers are uniquely beautiful. They have flowers made up of stiff, papery bracts in a wide array of colors. Their color holds when you dry them, and they’ last a long time. ‘re long-lasting.
They need full sun but are not picky about soil. They do need regular watering, or the plants will wilt. Afternoon shade is best in warm climates.
Rudbeckia
- Botanical Name: Rudbeckia spp.
- Sun Needs: Full sun
- Height: up to 8’
- Zones: 3-9
You may know these plants by the common name of the genre’s most well-known species, Black-eyed Susan. These bright and beautiful flowers are so easy to grow that the seeds are often scattered along roadsides. They are heat and drought-tolerant and easygoing about soil. They don’t need fertilizer, but they won’t turn it down if you offer.
If you start seeds in early spring these will begin blooming in late spring to early summer. They will continue to bloom until the first frost if they get enough water and care. It’s easy to find nursery starts of many species of rudbeckia. Their ease of care and floriferous nature make them a very popular plant.
Goldenrod
- Botanical Name: Solidago spp.
- Sun Needs: Full sun
- Height: up to 6’
- Zones: 2-8
Goldenrod is another plant that is easy to grow and care for. Once you plant it in your garden, you’ll never have to buy another plant. These self-seed nicely, though sometimes aggressively. You may be better off planting this one in an open area where it can spread out.
Some types are considered invasive, but native species are not. I personally shake mine to scatter the seeds, and they don’t multiply fast enough for my taste in the warm climate where I live. Nursery starts should be easy to find in late summer.
Plant your goldenrod in full sun. The tall leafy stems make a soft and beautiful backdrop for other flowering plants. These are perfect for a meadow or cottage garden.
They adapt to most soil types and prefer regular watering. Keep the soil moist while they establish roots. They make a stunning addition to cut flower arrangements.
Celosia
- Botanical Name: Celosia spp.
- Sun Needs: Full sun
- Height: up to 3’
- Zones: 10-11
A common name for these flowering plants is cockscomb, which comes from the unique flower formation of some varieties.
They certainly have a unique appearance and light up the garden in summer and fall. You could plant these from nursery starts or seeds, depending on your climate. In warm climates, they will have enough time to bloom from seed.
Keep the soil moist for your celosia plants. They prefer moderately fertile soil that is moist but well-draining.
They will grow in full sun or partial shade, but flowering will be best with six or more hours of sunlight daily. The flashy fall-blooming flowers are stunning and eye-catching in the garden and long-lasting as cut flowers.
Final Thoughts
I know working in the garden in late summer can be exhausting. That summer heat can zap your energy. I find gardening in the evening to be far more pleasant in the late summer months. Why not take advantage of the longer daylight hours? If you can brave the August temperatures, you’re sure to have a stunning garden full of blooming flowers in the fall.
