Do you look at the plants in your garden and wonder? why don’t they bloom?
I’m. And I discovered a surprising reason why my cosmos plants don’t even have buds on them.
So, to get to the bottom of what’s stopping garden plants from blooming, I asked local flower grower, Sue Oriel of Country Lane Flowers, to explain and suggest effective solutions.
Sue and her business partner Stephanie grow all the flowers for Country Lane Flowers in their own gardens. They create sustainable, locally sourced flower arrangements for weddings and supply bouquets, so if there’s one thing I can’t afford, it’s flowers that don’t bloom!
6 Reasons Why Your Plants Are Not Blooming
- You planted it in the wrong place in your garden
- Plant age (perennials only)
- Sowing seeds too late (only annuals)
- Not dead enough
- Pruning at the wrong time
- Insufficient fertilization or use of too much fertilizer
The #1 reason your plants aren’t blooming
You have placed it in the wrong position. ‘If you plant sun-loving plants in too much shade, they will become leggy with little or no flowers,’ says Sue.
Shade-loving plants such as foxgloves and hydrangeas will thrive 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 number one reason irises don’t flower is because their rhizomes are buried too deep. Not only does the iris plant need full sun, but it also needs sun at the top of the rhizome.
‘Full sun’ in the gardening world is defined as ‘six or more hours of direct sun per day in summer’.
How to fix it: move the plant to a place where it will get the right amount of sun. It is better to move the plants in spring or autumn. Summer can be too hot and dry, but winter can be too cold and wet.
If a plant needs full sun, such as a dahlia, then in deep shade it will bloom very little or not at all. This is Dahlia ‘The Wizard of Oz’
Plant age (perennials only)
Perennials are plants that live in your garden for three or more years. To learn more about them, see simple perennials.
I’m redecorating my border, so I’ve planted lots of 9cm perennials, such as jewelweed and hardy geraniums.
They have bloomed, but not large clusters of flowers. But that’s not surprising. Many perennials will take more than one summer to grow large enough to bloom profusely.
And at the other end of the spectrum, many perennials are spreading in the border. After three or four years, the original part of the plant will die in the middle leaving a ‘bald patch’ without flowers.
Sue says the way to deal with this problem is to dig up and divide clumps of perennials if you see the middle of the clump not blooming. This is best done in spring and autumn.
How to fix it: As Sue says, you may need to cut a particularly stubborn clump of perennials into pieces after digging it up. But you will be able to discard the old dead roots and replant a few sections of new roots.
“But sometimes plants just die. It’s normal,’ says Sue. A professional gardener once told her that you should plan to replace about 10% of the plants in your border each year.
The gem in my border was only planted a few months ago. They haven’t reached their full bloom yet – I hope so!
Sow seeds too late (annuals only)
Annuals are plants that are grown from seed, flower, then set seed and die, all within 12 months.
“Edible plants take 14-21 days to germinate and then 90-100 days of growth before flowering,” says Sue. ‘It’s simple math. If you sow the seeds too late, you don’t have enough time to flower before the temperatures drop and the daylight shortens.’
How to fix it: She says the answer is to sow the seeds of hardy annuals in the fall. Then keep them somewhere cool, but frost-free (like 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 planting the seeds the same year you want them to flower, Sue suggests leaving it no later than mid-spring (March for the Northern Hemisphere).
You’re not dead enough for your flowers
Sometimes you’ll see ‘dead flowers a week’ on gardening to-do lists.
Prune dead flowers as soon as they start to look even a little messy, like one of these Cosmos ‘Apricott’s’. He can’t even put ugly flowers in a bouquet or wedding decorations!
Deadheading encourages more blooms. If your plants are repeat bloomers, then frequent de-heading will stimulate them to pump out more flowers.
But what is ‘often’? When I interviewed Frances Moskovits about her amazing grass border, she told me she deadheads about four times a day. By that he means he keeps the scissors by the back door and in the shed. When she goes out into the garden, she grabs and cuts off all the flowers she can see pass by.
She recommended me Darlac snips. I bought a few pairs and dead heads much more regularly than before. (Note that Amazon links are affiliate, see disclosure)
How to fix it: Sue says she’s a deadhead three times a week. “But when flower growers pick their flowers, we also really die before the flower head dies! That’s why we have so many flowers – we cut them all the time!’
The RHS also recently recommended deadheading flowers as soon as they start to look shabby rather than waiting for them to die completely.
She says flower growers also deadhead down to the leaf node. ‘We don’t leave the stem. And it also encourages reblooming.’ There’s more about the deadhead here.
Not all plants bloom repeatedly. But repeat flowers include dahlias, cosmos, many roses, astranties, penstemons, hardy geraniums and more.
You’ll probably also want to leave some plants for seed. The seed heads look pretty in winter and provide food for birds. And if you’re harvesting your own seeds, you’ll also need seeds.
Regular removal of the head and cutting off the whole stem is the key to repeat flowering.
Pruning at the wrong time
I interviewed plant experts about growing specific plants, including hydrangeas, roses, salvias and irises.
I always ask the expert ‘why is my (insert plant name) not blooming?’
Neil Miller, head gardener at Hever Castle, where they have a famous rose garden, says the most common reason roses don’t bloom is that they are pruned too late.
Roses bloom on stems that grow in the same year. So if you prune your rose later than early spring, you will likely cut off this year’s flowering growth.
And Roger Butler of Signature Hydrangeas says the number one cause of hydrangeas not blooming is being pruned incorrectly. Different types of hydrangea need different types of pruning. Here is a really simple guide to pruning hydrangeas.
How to fix it: Find out when your plants need pruning – don’t just chop when you have time.
Insufficient fertilization OR using too much fertilizer
My interview with Neil Miller completely changed the way I grow roses. He explained that roses need more feeding 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, without flowers.
We had a big bag of fertilizer that someone gave me. Our puppy discovered it and tried to eat it, so I thought it would be a good idea to generally scatter it around the borders to get rid of it. I normally don’t use fertilizer except for certain plants. (See how the puppy proves his garden here)
My cosmos plants have grown green and lush with the extra fertilizer – but many have no flower buds on them. Sue says some plants – such as cosmos and geraniums – won’t flower if life is too easy for them.
I remembered last summer when I packed a large pot full of geraniums and tended to them very tenderly. I watered it and fed it. She had about two flowers. I have neglected geraniums in the past and they bloomed well.
How to fix it: Vegetables, roses and pots need extra fertilizer, but many other plants do not. So don’t just add fertilizer in the hope that it will improve flowering.
Check to see if the plant needs additional fertilizer – if you keep the soil in good condition, many don’t.
Watch a video on why your garden plants are not blooming
Watch an interview with Sue and a few more views of her garden in this video.
Pin to remember the common reasons why plants stop blooming
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