I used to think late August was only for sweeping up dried leaves and watching the garden slowly fade. Then I learned the secret that changed my spring plantings forever.
The prettiest spring beds do not start in April. They start in the dusty, late-summer heat of August.
By sowing cold-hardy annuals, biennials, and perennials now, you let them build strong root networks in the warm soil before cold weather hits. When spring arrives, they do not waste time settling in. They just erupt.
If you are not sure where your garden fits on the map, you can use the USDA Plant Hardiness Zone Map to find your exact zone. It is a quick check that saves a lot of seed-starting headache.
Here is my running list of what to sow now.
Quick Summary
- 10 cold-hardy flowers that establish roots in late summer to survive winter.
- Includes hardy annuals, biennials, and tough perennials.
- Best starter pick: Pansies & Violas because they handle freezing weather like champions.
1. Pansies & Violas (Viola)
| Sun | Full sun to part shade |
| Water | Medium, consistent moisture |
| Height | 6-8 in (15-20 cm) |
| Bloom | Late winter to early summer |
| Zones | 4-9 |
Violas are outstanding in pots, and they are easily my favorite choice for filling empty winter containers.
If you do not have much yard space, they are one of the best flowers to grow in containers to keep color on your patio when everything else is bare.
I started sowing these in late summer three years ago because I could not stand looking at empty, mud-filled beds all winter.
They sat under heavy snow for three months, and somehow they started blooming in February.
Tip: Keep the soil damp until the seeds sprout. Viola seeds are tiny and will fail if the soil dries out even once.
2. Calendula (Calendula officinalis)
| Sun | Full sun |
| Water | Low to medium |
| Height | 12-24 in (30-60 cm) |
| Bloom | Spring to frost |
| Zones | 5-11 |
Calendula is my absolute favorite for early salads and making dried flower teas.
I sow them in August because the warm soil makes the seeds sprout in just a few days.
They will grow a small rosette of leaves before winter, freeze solid, and then bloom weeks before any spring-sown seeds.
If you want flowers that return every year on their own, calendula is an excellent choice. I wrote about them in my guide on self-seeding flowers that keep your beds filled for free.
Care Note: Do not fertilize them. Rich soil makes them put out soft green leaves instead of orange blossoms.
3. Cornflower (Centaurea cyanus)
| Sun | Full sun |
| Water | Medium, well-drained |
| Height | 12-36 in (30-90 cm) |
| Bloom | Late spring to mid-summer |
| Zones | 2-11 |
Nothing beats that bright, electric blue color in the spring garden.
Cornflower seeds need cool soil temperatures to keep growing, so late August is the perfect window to get them started.
They spend the winter as a tiny rosette of fuzzy grey leaves that hug the ground.
In spring, they grow tall and start flowering almost overnight.
Warning: These grow so fast that they can flop over in heavy rain. Plant them near sturdier perennials for support.
4. California Poppy (Eschscholzia californica)
| Sun | Full sun |
| Water | Low, drought-tolerant |
| Height | 6-12 in (15-30 cm) |
| Bloom | Spring to summer |
| Zones | 6-10 |
I throw these seeds into the dry, gravelly patch next to my driveway.
Poppies hate being moved. Direct sowing them in August is the only way to get healthy plants.
They will sit quietly through the winter rain and reward you with bright orange petals in early spring.
Tip: Do not cover the seeds with soil. They need light to germinate, so just press them gently into the dirt.
5. Love-in-a-Mist (Nigella damascena)
| Sun | Full sun to part shade |
| Water | Medium, well-drained |
| Height | 12-20 in (30-50 cm) |
| Bloom | Late spring to mid-summer |
| Zones | 2-10 |
The feathery foliage is beautiful even before the flowers open.
Nigella seeds sprout quickly in warm late summer soil, forming a soft green carpet that survives frosts easily.
I love them because they fill the awkward gap in early spring when other plants are still waking up.
Warning: They self-seed easily. Cut the seed pods if you do not want them spreading throughout your garden beds.
The plants that survive my forgetting to water are the ones I keep planting more of.
6. Forget-Me-Nots (Myosotis sylvatica)
| Sun | Part shade to full shade |
| Water | Medium, consistent moisture |
| Height | 6-12 in (15-30 cm) |
| Bloom | Mid-spring to early summer |
| Zones | 3-8 |
These are perfect if you have tall trees blocking the sun.
I also keep a running list of other shade perennials that I use to fill dark corners of my yard.
Sowing forget-me-nots in August allows the biennials to establish rosettes that will form a thick blue carpet next spring.
They prefer moist, cool soil. I sow them directly under my hydrangeas.
Tip: Keep the area weeded. The tiny seedlings are easily crowded out by autumn weeds.
7. Larkspur (Consolida ajacis)
| Sun | Full sun |
| Water | Medium, well-drained |
| Height | 24-48 in (60-120 cm) |
| Bloom | Late spring to summer |
| Zones | 2-10 |
Larkspur gives you those tall, cottage-style flower spikes that look like delphiniums but are much easier to grow.
The Oregon State University Extension Service recommends sowing hardy annuals like larkspur in late summer to establish strong roots.
Here is my secret trick for sowing them in August.
Put your seed packets in the refrigerator for two weeks before planting. They need that artificial cold shock to wake up when the soil is still warm.
Once planted, keep the soil cool by mulching lightly with pine straw.
Warning: Every part of this plant is toxic. Keep it away from dogs that like to chew leaves.
8. Columbine (Aquilegia)
| Sun | Part shade to full shade |
| Water | Medium, well-drained |
| Height | 12-36 in (30-90 cm) |
| Bloom | Spring to early summer |
| Zones | 3-9 |
Columbine seeds are slow to sprout and require winter chill to break dormancy.
By sowing them in August, you let nature handle the cold treatment for you.
They will germinate in late autumn or early spring, growing into sturdy clumps that bloom by summer.
I find them much easier to start from seed outdoors than in trays on my windowsill.
Care Note: They like rich soil, so mix in a thin layer of compost before sowing the seeds.
9. Snapdragons (Antirrhinum majus)
| Sun | Full sun to part shade |
| Water | Medium, well-drained |
| Height | 12-36 in (30-90 cm) |
| Bloom | Spring to frost |
| Zones | 7-10 |
In warm zones, snapdragons sown in August will grow slowly through autumn and winter.
They will put out huge flower spikes as soon as the weather warms up in spring.
I always plant them along the front pathway where their sweet scent catches the breeze.
Warning: In zones colder than 7, these will not survive the winter outdoors. Sow them in spring instead.
10. Siberian Wallflower (Erysimum cheiri)
| Sun | Full sun |
| Water | Low to medium |
| Height | 12-18 in (30-45 cm) |
| Bloom | Early spring to mid-summer |
| Zones | 5-9 |
Wallflowers produce dense clusters of bright orange and yellow blooms with a sweet, honey-like fragrance.
Sown in August, they establish quickly in the warm soil and develop deep root systems before the winter freeze.
They are tough and grow well in poor, sandy soil where other plants struggle.
Tip: Pinch the growing tips of the young seedlings in autumn to encourage bushier growth in spring.
Common Questions
1. Will these seeds germinate in the hot August sun?
Yes, but you must keep them damp. The main reason autumn sowings fail is that the soil dries out. Water them gently every morning.
2. Do I need to protect the young seedlings in winter?
No, these are hardy annuals and biennials. They are designed to handle freezing temperatures. A light layer of leaves can help in very cold zones, but it is not required.
3. What if my seeds sprout and then it frosts early?
These plants form low rosettes that hug the ground. They are tough enough to survive early frosts without any issues.
What I Would Sow If I Only Had Room for One
If you only have space for one seed packet, make it California Poppies. They are cheap, grow in almost any soil, and that orange is the perfect spring welcome.
— Anh