A favorite flower for pollinators, cut flower growers, and pretty much anyone who loves a bold and cheerful flower, black-eyed Susans will pump out blooms from summer through fall. To capitalize on the full growing season and maximize the blooms you’ll get, it’s essential to plant your flowers at the right time of the year.
The best time to start black-eyed Susans directly in your garden is between March and May, as long as it’s after the last frost. You can also start seeds in the fall using the winter sowing method, or indoors up to ten weeks before the last frost for better chances of getting flowers in the first year.
The rest of this article will discuss how planting time affects when black-eyed Susans bloom and the options for fall and springtime sowing. I’ll also briefly touch on the seed-starting process.
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How planting time affects when black-eyed Susans bloom
The time you plant black-eyed Susans significantly affects when they’ll bloom, but it also depends on what varieties you grow. There are two main types:
- Biennial: Many gardeners treat biennial black-eyed Susans as annuals, allowing them to bloom during summer but die during winter. The plant’s seeds will germinate the next year and bloom again in the summer.
- Perennial: True perennial black-eyed Susans can be grown from seeds in the springtime, but they typically don’t produce flowers until the following year. If you want to find a perennial variety, check out my deep dive in this article, Are Black Eyed Susans Annual Or Perennial Flowers?
Regardless of whether the plant is an annual or perennial variety, the seeds will germinate when the soil temperature is around 70°F (21.1°C), making spring (after the last frost) or early fall the ideal time to plant.
Spring sowing black-eyed Susans
Sowing black-eyed Susans in the spring is the best time, as the seeds have the proper amount of time and the right temperature to germinate. The seedlings will also establish roots before the hot summer months.
While you’re not always guaranteed to get flowers by the summer or fall of that year, the chances are higher, especially if you start the seeds indoors to make a longer growing season.
Determine when the last light freeze in spring is for your area, so you can plan to germinate your black-eyed Susan seeds before that date. Beginning the germination process indoors anywhere from 6-10 weeks before the last frost will give you a headstart, increasing your plant’s chances of blooming that same year.
Black-eyed Susan is a slow grower as a seedling, so you need a solid chunk of time to get them going. Once the weather warms up outside, they grow much more quickly.
For perennial varieties, planting outdoors in the spring is ideal. However, they may need to overwinter before producing flowers. Perennials naturally take longer to bloom than annuals or biennials.
Fall sowing black-eyed Susans
While sowing black-eyed Susans in the spring is ideal, you can also sow them during the fall months. However, don’t expect the flowers to bloom that year, as they need to establish their roots first.
If you want to sow black-eyed Susans later in the year, you must do so during the early fall, so your seeds have time to germinate and establish roots before the weather gets too cold. Germination can take anywhere from a week or two, so work out the timing for the best date to plant the seeds.
For fall sowing, you can again start the seeds indoors and transplant them out in the fall, or you can direct sow the seeds in the garden. Both methods will give the plants time to mature enough to survive the winter, then take off with new growth in the spring.
Once the seeds have germinated and established roots, the plant can tolerate low temperatures. Black-eyed Susans are winter-hardy plants that can tolerate temperatures as low as -30°F (-34.4°C).
After planting seeds in early fall, you’ll likely see the plant begin flowering by the following spring or summer.
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When you know what condition your soil is in, it’s much easier to add anything that’s missing before your plants start to suffer.
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Find the rest of my “use on the daily” garden gear on my resources page.
Black-eyed Susan seed starting process
If you want to start your black-eyed Susan seeds indoors during winter to get a headstart, you’ll need to following supplies:
- Planting trays
- Grow lights
- Seed starting medium
- A heat mat
Then, follow these simple steps:
- Add your seed-starting medium to the planting trays. Place the trays next to a window receiving adequate morning light.
- Create a small indention in each section of the tray and add the seeds to each one. Don’t make these holes too deep, as the seeds need adequate sunlight to germinate.
- Leave the soil uncovered. Black-eyed Susan seeds need light to germinate.
- Keep the soil moist. Mist the seeds at least once daily to prevent them from drying. Once they sprout, you can bottom water, but at this point, they don’t have roots to draw up the water.
- Place the tray on a heating pad. Keep the temperatures steady at around 70 °F (21.1 °C) until the seeds germinate.
- Move the germinated seedlings underneath the grow lights for the next 8-10 weeks. After the last frost, you can transfer the seedlings outdoors.
For more information on starting seeds indoors, check out my step-by-step guide here: Growing Black Eyed Susan From Seed: Q&A and How To Start
If you don’t want to start your flower seeds indoors, you can just plant them outdoors when the weather permits. The steps are relatively similar:
- Wait until after the last frost of the year.
- Find a place outdoors that receives adequate sunlight. Black-eyed Susans prefer full sunlight to encourage germination and blooming.
- Spread the seeds on the ground and lightly cover them with ¼ inch (0.63 cm) of soil.
- Keep the ground moist to help the seeds germinate successfully.
After doing this, you’ll notice the seeds usually germinate within a week. However, these seeds most likely won’t grow and bloom until the following spring.
Don’t forget to check your local nursery in the spring for transplants. Last year I got lucky and found several varieties of black-eyed Susan flowers, which helped me get a jump on summer blooms.