Look at plants in your garden and ask yourself why aren’t they blooming?
I am. And I discovered a surprising reason why my cosmos plants don’t even have buds.
To find out what’s stopping garden plants from blooming, I asked local flower grower Sue Oriel of Country Lane Flowers to explain it and suggest effective solutions.
Sue and her business partner Stephanie grow all of the flowers for Country Lane Flowers in their own gardens. They create regional, sustainable floral arrangements for weddings and deliver bouquets. So if there’s one thing they can’t afford, it’s flowers not blooming!
6 reasons why your plants aren’t blooming
- You planted it in the wrong place in your garden
- The age of the plant (perennials only)
- Sowing your seeds too late (annual plants only)
- Not dead enough
- Pruning at the wrong time
- Not fertilizing enough or using too much fertilizer
The main reason why your plants are not blooming
You planted it in the wrong place. “If you plant sun-loving plants in a location that is too shady, they will become leggy and have few or no flowers,” says Sue.
Shade-loving plants like foxgloves and hydrangeas bloom in the shade.
But sun lovers like lavender, cosmos, dahlias, zinnias, sunflowers and more need full sun.
Iris experts at Irises of Sissinghurst say the main reason irises don’t flower is because their rhizomes are buried too deeply. The iris plant itself not only needs full sun, but also sunshine on the top of the rhizome.
“Full sun” is defined in the gardening world as “six hours or more of direct sunlight per day in the summer.”
How to fix the problem: Place the plant in a location where it gets enough sun. It is better to move plants in spring or autumn. Summer can be too hot and dry, but winter can be too cold and wet.
If a plant like a dahlia needs full sun, it will flower very little or not at all in deep shade. This is Dahlia “Wizard of Oz”
The age of the plant (perennials only)
Perennials are plants that live in your garden for three years or more. For more information, see Perennials Made Simple.
I am redesigning my bed and have planted many 9 cm high perennials, for example geums and hardy geraniums.
They have bloomed, but they are not huge clusters of flowers. But that’s not surprising. Many perennials need more than one summer to grow large enough to bloom profusely.
And at the other end of the spectrum, many perennials spread throughout the bed. After three to four years, the original part of the plant dies in the middle, leaving a “bare spot” with no flowers.
Sue says you can deal with this by digging up clumps of perennials and dividing them if you see that the center of the clump is not blooming. This is best done in spring and fall.
How to fix the problem: As Sue says, you may need to chop a particularly stubborn clump of perennials into pieces after you’ve dug them up. But you can throw away the old dead roots and replant several sections with new roots.
“But sometimes plants just die.” “That’s normal,” says Sue. A professional gardener once told her that you should replace about 10% of the plants in your bed each year.
The geums in my bed were only planted a few months ago. They haven’t reached full bloom yet – I hope!
Sowing too late (only annual plants)
Annuals are plants that grow from seed, flower, then set seed and die within 12 months.
“Annual plants take 14 to 21 days to germinate and then 90 to 100 days of growth before flowering,” says Sue. “It’s simple math. If you sow the seeds too late, you won’t have enough time to reach flowering before temperatures drop and daylight becomes shorter.”
How to fix the problem: She says the answer is to sow seeds of hardy annuals in the fall. Then store them in a cool but frost-free place (such as a greenhouse or windowsill) over the winter.
Not all seeds can be planted in the fall to bloom the following summer. So if you’re sowing the seeds the same year you want them to flower, Sue recommends leaving the plant no later than mid-spring (March in the Northern Hemisphere).
Don’t trim your flowers enough
Sometimes you see “weekly dead flowers” on gardening to-do lists.
Sue wilted blooms as soon as they look even a little unkempt, like one of these Cosmos ‘Apricotta’. She can’t even put slightly shredded flowers into a bouquet or wedding decoration!
Cutting off inflorescences encourages more vigorous flowering. If your plants bloom repeatedly, cutting off the buds frequently will encourage them to produce more flowers.
But what is “common”? When I interviewed Frances Moskovits about her amazing perennial border, she told me that she deadheads about four times a day. By this she means she keeps scissors by the back door and in the shed. When she goes into the garden, she takes the secateurs and cuts off all the flowers that grow over her head.
She recommended Darlac snippets. I bought a few pairs and have been using the Deadhead much more regularly than before. (Please note that the links to Amazon are affiliate links, see disclosure)
How to fix the problem: Sue says she does deadheads about three times a week. “But when flower farmers harvest their flowers, we practically cut them off before the flower head dies!” That’s why we get so many flowers – we always cut them!’
The RHS has also recently recommended that you should cut off flowers as soon as they look shabby, rather than waiting for them to die completely.
She says flower growers also cut the head down to the leaf node. “We don’t leave a stalk behind.” And that also encourages repeat flowering.” Learn more about dead-heading here.
Not all plants bloom repeatedly. However, repeat bloomers include dahlias, cosmos, many roses, astrantias, penstemons, hardy geraniums and more.
You may also want to leave some plants standing so they can be sown. Seed heads look beautiful in winter and provide food for birds. And if you harvest your own seeds, you’ll also need seed heads.
Regular stem cutting and cutting off the entire stem is the key to repeat blooms.
Pruning at the wrong time
I interviewed specialized plant experts about growing specific plants, including hydrangeas, roses, sage and irises.
I always ask the expert, “Why isn’t my (insert plant name) blooming?”
Neil Miller, head gardener at Hever Castle, where there is a famous rose garden, says the most common reason roses fail to bloom is because they have been pruned too late.
Roses bloom on stems that grow in the same year. So if you prune a rose later than spring, you’re probably cutting off that year’s blooms.
And Roger Butler of Signature Hydrangeas says the main cause of hydrangeas not blooming is that they have been pruned incorrectly. Different types of hydrangeas require different types of pruning. Here’s a really easy guide to pruning hydrangeas.
How to fix the problem: Find out when your plants need pruning – don’t just chop away when you have the time.
Not fertilizing enough OR using too much fertilizer
My interview with Neil Miller completely changed the way I grow roses. He explained that roses require more food and fertilizer than most plants.
I now use a rose fertilizer and it has transformed my roses. They have more than twice as many flowers as before.
But too much fertilizer can cause other plants to turn green and leafy and not produce flowers.
We had a big bag of fertilizer that someone gave me. Our puppy spotted it and tried to eat it, so I thought it would be a good idea to generally spread it around the edges to get rid of it. I don’t usually use fertilizer except for certain plants. (Here’s how to puppy-proof your garden)
My cosmos plants have become green and lush thanks to the additional fertilizer – but many have no flower buds. Sue says some plants – like cosmos and pelargoniums – won’t bloom if their life is too easy.
I thought back to last summer when I packed a large pot full of geraniums and cared for it very lovingly. I watered it and fed it. It had about two flowers. In the past I have neglected geraniums and they have bloomed quite well.
How to fix the problem: Vegetables, roses and pots need additional fertilizer, but many other plants do not. So don’t just add fertilizer hoping it will improve flowering.
Check to see if a plant needs additional fertilizer – if you keep your soil in good condition, many don’t.
Watch the video why your garden plants are not blooming
Watch the interview with Sue and some more views of her garden in this video.
Pin to remind you of common reasons plants stop blooming
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