Are Black Eyed Susans Annual Or Perennial Flowers?
A cheerful, yellow, daisy-like flower, black eyed Susan, also known as rudbeckia, is a reliable beauty in the garden. Often returning year after year, black eyed Susan will throw out stems that are perfect for enjoying in the garden, cutting for the vase, or left for the birds and bees to find food.
Even though black eyed Susans return to the garden each year, classifying them as an annual or perennial is actually a tricky task that doesn’t always have a straightforward answer.
Black eyed Susan, also known as rudbeckia, is available in biennial and perennial varieties. Rudbeckia hirta is biennial but often grown as an annual and started from seed each spring. Rudbeckia fulgida is a true perennial, hardy to USDA zone 4 and above.
So really, black eyed Susan can fit into all three classifications of plants, and climate will play a significant role in which category it falls under. Here’s a look at some of the most commonly grown varieties of black eyed Susan:
|Variety||Biennial or perennial||Appearance|
|Indian Summer||biennial||single flowers with solid golden yellow petals, brown center|
|Cherokee Sunset||biennial||double flowers in orange, copper, and yellow, brown center|
|Prairie Sun||biennial||two-tone single flowers in orange and yellow, green center|
|Cherry Brandy||biennial||single flowers in cherry red, brown center|
|Goldstrum||perennial||single flower with yellow petals that point downward|
|Early Bird Gold||perennial||single flowers with yellow petals, large brown center|
|Rudbeckia triloba||biennial||smaller single yellow flowers, brown center|
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Are Black Eyed Susan Annual Or Perennial Flowers?
Even though black eyed Susans are often grown as annuals, they are classified as biennial or perennial.
Black eyed Susans are biennial or perennial flowers, but they are flexible enough in their growing requirements that many are grown as annuals. If the seeds are started early in the spring, the plants will flower the first year. Perennial varieties will survive from year to year as long as the winter temperatures aren’t too severe.
There are over two dozen species of black eyed Susan, whose real name is actually rudbeckia. Black eyed Susan is the name most commonly used, but the name rudbeckia is used to distinguish between species.
I had a lot of trouble understanding if black eyed Susan and rudbeckia were the same plant when I first started growing them. To help sort it all out, I wrote this article, Is Black Eyed Susan The Same As Rudbeckia (plus other lookalikes). If you’re in the same boat, I hope it will clarify things for you, too!
Rudbeckia hirta is the more commonly grown black eyed Susan, classified as a biennial. Biennials establish themselves in the fall with strong roots and leaf growth, overwinter, then resume growth in the spring to bloom in the summer. So they technically grow over two years, which earns them their name as a biennial.
The second most popular species of black eyed Susan is Rudbeckia fulgida, a true perennial, meaning that the same plant returns every year in spring. As long as the roots survive the cold and rain of winter, the plant will live for many years, spreading a bit more each year and producing more flowers.
Both species can be grown as annuals, which means the plant completes its whole life cycle in one growing season. If this is your goal, start seeds indoors about six weeks before your last spring frost.
Black eyed Susans need about 100 days from their transplant date to bloom, so that six weeks will give the seedling a jump on the season and leave enough time for that long period of growth.
The flowers will bloom all summer long, and at the end of the season, you can leave some flowers on the plant to go to seed. Birds will eat some seeds, but more than likely, some will also make it to the ground where they’ll sprout on their own the following spring.
I go into further detail about letting some of your flowers go to seed in this article, Know When To Cut Back Black Eyed Susan For Optimal Growth.
Does black eyed Susan come back every year?
Most varieties of black eyed Susan will return year after year, whether they are classified as a biennial or a perennial. The biennial varieties are prolific self-seeders, dropping seeds in the fall that sprout and grow the following spring. Perennial varieties will regrow from the same roots year after year.
Some gardeners even avoid growing black eyed Susan because they self-seeded too freely. If you want to keep your black eyed Susan contained, you can remove the flowers before they go to seed, or pull out seedlings as you see them sprout.
Even perennial black-eyed Susan may not return from year to year in frigid climates. If the soil freezes for too long, cold will damage the plant roots and prevent regrowing in the spring.
You can try mulching your plants heavily through the winter to help insulate the roots and protect them from damage. Woodchips, leaves, and even wool can make a great organic mulch to help your black eyed Susans survive the winter in colder climates.
Frost heave is another potential plant killer. Frost heave is the result of the ground freezing and thawing repeatedly. With each cycle, a plant’s roots are pushed out of the ground until the plant itself is several inches above the soil line. Exposure to air and cold temperatures kills the root system if the plant isn’t replanted right away.
Adding an insulating layer of organic mulch can help prevent frost heave by stabilizing the soil temperature, but it isn’t a sure thing, so if you live in a climate that freezes and thaws frequently throughout the winter, keep an eye on your black eyed Susan.
If they start to work their way out of the ground you’ll need to replant them right away to make sure they survive to return in the spring. If the ground is too frozen to replant them, tuck them into a pot filled with soil and store them in a shed or garage until spring.
While you’re working out your plan for which black eyed Susan to grow and whether to fill your garden with annuals or perennials, check out this article to get some ideas for other plants to include alongside: Companion Plants For Black Eyed Susan: Garden and Bouquet.
Plus, get even more growing information in this article: Black Eyed Susan: A Complete Guide To Growing.