You may be wondering if your plants aren’t blooming.
I am. I have discovered the surprising reason for why my cosmos plant doesn’t even show any buds.
To find out what is stopping garden plants from blooming, I asked Sue Oriel, a local flower farmer at Country Lane Flowers, to explain the problem and offer some solutions.
Sue and Stephanie, her business partner, grow the flowers in their gardens for Country Lane Flowers. They supply sustainable, locally-sourced flower arrangements and bouquets for weddings. If there is one thing that they cannot afford, it’s flowers that aren’t in bloom!
There are 6 reasons your plants may not be flowering
- It’s in the wrong part of your garden
- Age of the plant only (perennials)
- You can’t sow your seeds in the spring (annuals only).
- Not enough deadheading
- When to prune
- Use too much or not enough fertilizer
Why your plants don’t bloom?
It’s in the wrong place. If you place sun-loving flowers in a shady spot, they will become leggy and have few or no blooms, says Sue.
Shade-loving plants such as hydrangeas and foxgloves will flower in the shadow.
Sun-loving plants, like lavender, dahlias, and sunflowers, as well as cosmos and dahlias, need full sunlight.
Irises of Sissinghurst, iris experts in the UK, say that if rhizomes have been buried too deeply, then this is the main reason why irises do not flower. The iris needs full sun on its own, but also the top of the rhizome.
In the world of gardening, ‘full sun’ is defined as six hours or more per day of direct sunlight in summer.
Fix it: Move the plant into a place where it gets the correct amount of sunlight. You should move your plants in the spring or fall. Winter can be cold and wet, while summer can be hot and dry.
In deep shade, a plant that needs full sunlight, like a dahlia, for example, will not flower or only very little. Dahlia “Wizard of Oz”
Age of the plant only (perennials)
Perennials live in your garden for three years or longer. Perennials Made Simple will tell you more.
I am renovating my border, so I have lots of perennials 9cm in size, such as hardy geraniums and geums.
The flowers are not large clumps. It’s not surprising. Many perennials will need more than one growing season to reach a size that allows them to bloom profusely.
On the other side of the spectrum are many perennials that spread along the border. After three to four years, the original plant part will die in the middle, leaving a bald patch with no flowers.
Sue advises that you should dig up the perennial clumps and separate them if the center of the clump does not flower. This should be done in the spring or autumn.
Fixing it: Sue said that you might have to cut a stubborn perennial clump into pieces after you’ve dug them up. You can throw out the old roots and plant several new sections.
“But sometimes plants simply die,” says Sue. Sue says, “That’s normal.” She was once told by a professional gardener that she should replace about 10% of her border plants every year.
My geums were planted only a few short months ago. They still haven’t bloomed to their fullest potential – I do hope!
The seeds are sown too late
Annuals are plants that are grown from seeds, flowers, and set seeds within a 12-month period.
Sue says that annuals require 14-21 days for germination and then 90-100 days of growth before they bloom. It’s just simple math. You won’t be able to flower your plants before the temperature drops, and the day gets shorter if you plant the seeds too late.
Fixing it: According to her, the solution is to plant seeds of hardy annuals during autumn. Keep them in a cool, frost-free place (like a window sill or greenhouse) for the winter.
Some seeds cannot be planted in the autumn for them to bloom the summer after. If you plan to plant seeds in the same year that you expect them to bloom, Sue recommends planting no later than the middle of spring (March for the northern hemisphere).
Not dead-heading your flowers enough
You’ll often see gardening lists that include ‘deadhead flower weekly.’
Sue deadheads flowers the moment they start to look scruffy. Like these Cosmos “Apricotta”. She won’t use even slightly scruffy flowers in a wedding bouquet or decorations.
Dead-heading promotes flowering. Dead-heading your plants will encourage them to produce more flowers if they are repeat-flowering.
What is “frequently”? When I asked Frances Moskovits how she maintains her incredible herbaceous border, she said she dead-heads four times per day. She means she keeps snips near the back door or in the shed. She takes snips with her and dead-heads all the flowers that she sees going over.
She recommended Darlac scissors. I purchased a few pairs of snips and now dead-head more often than before. Note that Amazon links are affiliates, see disclosure.
How to fix Sue’s dead-heads three times per week. “But when flower farmers harvest their flowers, we also dead-head before the flower heads have died!” We always cut flowers, so we have a lot of them.
RHS also recommends that you dead-head your flowers as soon they begin to look ragged rather than waiting until they die completely.
She claims that flower farmers dead-head their flowers down to the leaf node. We don’t leave any stalks. This encourages flowering to continue.
Not all plants flower again. Dahlias are repeat-flowerers, as well as cosmos and many roses.
Some plants will also go to seed. In winter, seed heads are beautiful, and they provide food for birds. If you want to harvest your own seed, you will need the seedheads.
To ensure that flowers continue to bloom, it is important to regularly deadhead and remove the entire stalk.
When to prune
I interviewed plant experts about growing specific plants, including hydrangeas, roses, salvias, and irises.
Why isn’t my (insert name of plant) flowering?
Neil Miller, the head gardener of Hever Castle’s famous rose garden, says that roses that don’t flower are usually pruned too late.
Roses bloom on stems which grow the same year. If you prune your roses later than the early spring, then you are likely cutting off this year’s flowering growth.
Roger Butler of Signature Hydrangeas says that the most common reason hydrangeas don’t flower is because they have been pruned incorrectly. Different types of hydrangea require different pruning. Here’s a simple guide on how to prune hydrangeas.
Fix it: Know when to prune your plants – don’t wait until you have time.
Too much fertilizer OR not enough fertilizer
Neil Miller’s interview with me completely changed the way I grow roses. he explained that roses require more fertilizer and feeding than other plants.
My roses have been transformed since I started using a rose fertilizer. They are more than twice as many flowers now.
Too much fertilizer will cause plants to grow green and left but without flowers.
Someone gave me a large bag of fertilizer. It was discovered by our puppy, and he tried to eat some of it. I decided to scatter it around the borders so that it wouldn’t be found. I only use fertilizer for certain plants. See for tips on how to dog-proof your garden.
The extra fertilizer has made my cosmos plants lush and green, but they haven’t produced any flower buds. Sue says some plants, such as pelargoniums and cosmos, won’t bloom if they have an easy life.
I remembered last summer when I had packed a large pot of pelargoniums. I took great care of them. I fed and watered the plant. It had two or three flowers. I have neglected pelargoniums in the past, and they have flowered fine.
Fix it: Veg, roses, and containers need extra fertilizer, but many other plants do not. Don’t add fertilizer in the hope of improving flowering.