skip to main content

Landscape Design Native Plants

question on biennial flowers (such as Black-Eyed Susan)

8 months ago

I'm trying to see if I understand how biennial flowers works. If a flower is biennial, does that mean it will not flower until its second year? And, once the plant flowers, those particular flowers/plants will die after one year and not return. However, the dried seedheads will release new seeds, so that the cycle always continues...the plant is constantly self-sowing. So while the individual plants/flowers are considered Annuals,, they take two-years to each develop, and even though they die after that, in some ways it's Perennial only because it self-sows so readily..

Do I sorta have that right? Or may I indeed need to toss a few additional BES seeds onto the site, every year, to ensure a continual good-sized patch of BES flowers in my garden?

Thanks!

Sort by:Oldest

Comments (4)

floral_uk z.8/9 SW UK
8 months ago
last modified: 8 months ago
Correct up until the end of the third sentence. Then it gets confused.

Annuals are plants which grow from seed, flower, produce seed and die within a single growing season. So biennial flowers cannot be considered annual. Depending on the plant and the length of the season they may go through this cycle several times. They might self sow but the original plant will not survive into the next year. Self sowing does not make a plant perennial.

Perennials grow from seed and may or may not flower in their first season. It might seed around but the original plant keeps going. Thereafter the plant lives for several, or even many, years.

Black Eyed Susan can refer to two different genera but I assume you mean Rudbeckia. Some are annual, some are biennial and some are perennial. It depends which species of Rudbeckia you are dealing with.
gardengal48 (PNW Z8/9)
8 months ago
last modified: 8 months ago
That is sorta right :-) A biennial is nether an annual (completes life cycle in a single season) nor perennial (lives for 3 or more years under normal care). A biennial completes its life cycle in two years, growing from seed in the first season but producing only foliage its first year. The second year it will flower, set seed and then die. The terms 'annual', 'biennial' or 'perennial' only refer to the plant's lifespan - 1, 2 or 3+ years.

Rudbeckia hirta - only one of several plants referred to as black eyed Susan - can behave as an annual, biennial or short-lived perennial depending on growing conditions and specific cultivar. Biennials generally display more flexibility in their life cycle than either true annuals or perennials, sometimes growing and flowering in a single season or living longer than 2 years. Most other species of Rudbeckia are fully perennial.

Self seeding with a biennial is usually a given - rudbeckia, hollyhocks, parsley, lunaria and foxgloves all tend to self seed very freely, to the point that once you have them planted, they will return continuously as long as they are allowed to go to seed.

ETA: typing at the same time floral was posting
Related Discussions
Black-eyed Susan & Purple Coneflower flowering from seed
Q
Comments (7)
In my experience, Cone Flower will bloom the 2nd year from seed here in my z7 NC garden. I sowed them in a flat, potted them up as seedlings, then planted them into the garden last year. This year they came back and bloomed for the first time. I dont know if this everyone's experience, but that is what happened here.
...See More
Black Eyed Susan
Q
Comments (5)
Rudbeckia fulgida 'Goldstrum' is a perennial. It is one of the toughest perennials in my experience, and one of my favorites summer/late summer long bloomers. And they do self seed so you may see a few more plants next year, and so on. So give it some space if you want to have more of them. And they add so much color and life to the late summer garden.They do like afternoon sun! If they are perky in the AM, you do not need to water them. For the first 4-6 weeks after planting, give it a good watering ~ once or twice/week (depending upon temp, rain, etc). If they do not perk up if the AM, water them. After first year, you typically do not need water any more. This year during the long, hot and dry late June and July, I watered them a couple times, that is all I did for the entire summer. Best of luck! Vivian from Northwest Subs of Chicago
...See More
Black - Eyed Susans really short-lived ?
Q
Comments (13)
I have had very different results with Black eyed suzi's. I had some rather plain ones, that where doing fabulous prior to our moving. Now I will never know the fate of them, but year over year they where thriving, increasing in size, probably by 2 to 3 times every year. I have a hard time to believe that next spring they would not come up again, unless the new home owner removed them! lol. Now, I had some really pretty Gloriosa Daisys, they where yellow with a green eye, huge flower, and really they are a black eyed suzi, I planted 3, the next spring only 1 came up. Although it florished that year! That is just how the cookie crumbed! lol. I think if you want to grow these flowers and want them to stick around, the best bet is to plant the more plain varieties, mulch them in the fall (make sure to remove excess mulch in the spring) and perhaps spread some new seed into the planting in the fall. Otherwise, you just sort of roll the dice! The best news is, they are surprisingly easy to grow from seed! And not expensive at all that way!
...See More
Black Eyed Susan Vine Dropping Flowers
Q
Comments (2)
What growing conditions are they in? They like lots of sun and even moisture IME. I've never grown salmon colored ones and am not growing any yellow ones this year to check how long blossoms last, but the years I have grown them, it's been in a large deep pot (more than 1' in all directions) in a sunny spot with regular watering. They are a bit slow to start, but by this time of year mine were generally multistemmed and most of the way up a 3'-4' trellis and covered with blooms. Since there were a lot of blooms, even if each individual bloom didn't last long, it still had lots of bloom. So I am not sure why, but yours seem like perhaps they aren't getting all they need or perhaps the salmon colored plants aren't as vigorous as the yellow and orange ones that I've grown. If you add info on your zone and location, it helps with questions like this since different plants behave differently in different locations. Here's how: Go to Your Houzz in the upper right of every page, click Edit Profile, and on the left side click advanced settings. Well down the advanced settings page is a blank labeled Climate Zone for Garden Forums along with a link to find your zone. If you add info on your state or the nearest large city you will get even better information since zone only relates to average coldest winter temperatures. Then return to the top of the page and click Done Editing.
...See More
Lynn Nevins
Original Author
8 months ago
Thank you both. Sounds like I'm 'covered' overall...that I should indeed see BES coming back every year. And I have a backup supply of new seeds just in case. And 'yes', the cultivar I have is Rudbeckia Hirta. ;-)
Lynn Nevins
Original Author
8 months ago
So....guess what I just noticed tonight?? I was quite sure that what I had were indeed BES seedlings (that I sowed in May).

Is it possible I'm already getting flower buds??

Related Stories

GARDENING GUIDES Great Design Plant: Black-Eyed Susan

By Becky Harris

Plant seeds this fall for rich swaths of golden blooms in the garden come summer

FLOWERS Rudbeckia Mania: Go Beyond Black-Eyed Susan in the Garden

By Benjamin Vogt / Monarch Gardens

Branch out from typical nursery fare, with lesser-known Rudbeckia species that have delightfully unexpected features

GARDENING GUIDES No-Regret Plants: 5 Questions Smart Shoppers Ask

By Jocelyn H. Chilvers

Quit wasting money and time at the garden center. This checklist will ensure that the plants you're eyeing will stick around in your yard

GARDENING GUIDES Plant Native Annual Flowers for a Garden Surprise Every Year

By Curtis Adams

These 15 well-adapted native annuals can add spontaneity to gardens around the country

COLOR Dreaming in Color: 8 Eye-Opening Yellow Bedrooms

By Jennifer Ott Design

Start your day energized and cheerful with bedroom hues that sing of sunshine or golden fields

GARDENING FOR BUTTERFLIES Butterfly Gardening: Delight the Eyes With Living Sculptures

By Benjamin Vogt / Monarch Gardens

Surprise and thrill with a garden that attracts magical winged creatures, bringing color, movement and life

EXTERIORS Curb Appeal Feeling a Little Off? Some Questions to Consider

By Becky Harris

Color, scale, proportion, trim ... 14 things to think about if your exterior is bugging you

GARDENING GUIDES 8 Flowering Vines to Plant for Nonstop Summer Blooms

By Lauren Dunec Hoang

Bursting with colors ranging from fiery red to purple, these showy climbers will carry your garden through summer

GARDENING GUIDES Attract Hummingbirds and Bees With These Beautiful Summer Flowers

By Annie Thornton

Roll out a welcome mat for pollinators to keep your landscape in balance and thriving

MOST POPULAR 11 Reasons to Paint Your Interior Doors Black

Brush on some ebony paint and turn a dull doorway into a model of drop-dead sophistication

Sponsored

SURROUNDS Landscape Architecture + Construction

10 Reviews

DC Area's High-End Custom Landscape Design/Build Firm 9x Best of Houzz

More Discussions

Cost of Landscaping in Northern Virginia

21

UGLY Street view. help!

4

How can I improve the usability of my backyard?

20

how should i trim this okame cherry

16

Railing for cottage landing and stairs

6