June 10th, 2018
Posted In: Gardening know how
Self-seeding plants are the key to gardening on automatic. The less you do, the more they grow.
And they’re free. You buy one packet of seeds or one plant, and get a lifetime of exuberant flowers.
Sometimes self-seeders even arrive in your garden without you buying anything at all!
I counted over 25 different kinds of self-seeding plants when I originally wrote this post. Now, six years later, most of those self-seeders are still filling my garden with free, beautiful flowers.
Most of these grow in a wide range of zones and climates.
And because self-seeded plants have chosen where they want to grow, they need very little care. You won’t have to fertilise or water them. You probably won’t even have to stake them.
All you need to do is pull them out if they stray too far.
This section of the main border is wholly self-seeded: alliums, euphorbia, rosa glauca and crocosmia…
Do I actually ever plant anything?
I promise I do. But without self-seeders, my garden would be much less vibrant. And I would have to spend much more time and money on it.
This year, self seeding flowers mean that I haven’t had to buy or grow any extra annuals to fill gaps.
What exactly are self-seeding plants?
When looking at plants that spread in the garden, ask yourself ‘is this a self-seeder or a clump-former?’ Clump forming plants spread outwards from the original plant, but they stay broadly where you planted them.
A self-seeding plant is one which plants itself by dropping seed. If you’re lazy about dead-heading, then self-seeders will turn to seed and drop the seed on the ground.
It will often pop up in a completely different part of the garden from where you originally planted it.
That’s because the wind or birds may also carry the seed, so the new plants can pop up from a neighbour’s garden – or even from quite a distance. I had always wanted some borage and one day it appeared. It has now self-seeded around the base of a rose, covering those bare stems.
Borage self-seeds itself in big clumps, with a soft grey foliage and a profusion of tiny blue flowers. Adored by pollinators. Borage is hardy down to minus 45C/minus 50F.
My two most prolific self-seeders are wild gladioli and euphorbia. Gladioli communis is hardy to minus 23C/minus 10F as is Euphorbia oblongata.
Some plants, such as day lilies, have all expanded from one or two tiny plants into huge clumps. But they don’t wander round the garden, establishing themselves wherever they see fit. So I don’t call them self-seeders.
Which plants self-seed in your garden can depend on your soil type as well as how good you are at weeding and dead-heading.
Do self-seeded flowers come back year after year?
It depends. I’ve found that some plants are very efficient self-seeders, but others perform less well.
And it varies from year to year. One year, I have lots of self-seeded amaranth. The next year, I often find just a few scraggly stalks of amaranth.
Aquilegias and eryngium are both defined as top self-seeders by Gardeners World, but I have planted one or two aquilegias. They have very gently self-seeded but I still only have a couple, and they’re near where I planted their parent plants. I wouldn’t call them a top self-seeding plant for my garden.
It’s the same for eryngium, which has also stayed where I planted it, without invading anywhere else.
We have clay soil, by the way, with some flint. And we roughly equate to a USDA hardiness zone of 9, with winters that rarely go more than a few degrees below freezing. However, our summers are not usually as hot as a USDA zone 9 – the average summer day’s temperature is rarely hotter than 25C/77F.
My very favourite self-seeder
Wild gladioli
One of our friends was born in this house in 1939. He remembers the wild gladioli in the garden when he was a very young boy. It’s likely that they were already well established by then as most gardening in the Second World War was growing for food.
Botanical artist Jane Elizabeth Giraud grew up in this house in Victorian times. And she painted wild gladioli.
So these wild gladioli have been in this garden for a hundred years or more. It’s their garden, more than it’s mine.
Gladiolus communis subsp. ‘Byzantinus’ to give wild gladioli its proper name. It comes from the Mediterranean but has been grown in Britain for centuries. In our front garden it lines itself up along the wall. My favourite self-seeder, because of its history. Hardy to minus 23C/minus 10F.
The best self-seeding flowers
Cerinthe major purpurescens (Honeywort)
After wild gladioli, my number two self-seeder is cerinthe. It’s an unusual looking plant, and people always ask ‘what’s that?’ But it’s no trouble at all.
I grew some cerinthe (Cerinthe major ‘Purpurescens’) from seed about fourteen years ago. They didn’t do particularly well, but the following year, they established two self-seeded clumps in the garden, and have thrived on total neglect ever since. Cerinthe is hardy to minus 45C/minus 50F.
Alliums ‘Purple Sensation’ and Christophii
These are the self-seeding plants I couldn’t do without. I find that both Allium ‘Purple Sensation’ and Allium Christophii self-seed vigorously. I originally bought 15 Purple Sensation about ten years ago, and now have around 50.
The tall lollipops are Allium ‘Purple Sensation’ and the shorter pale lilac fireworks are Allium Christophii. Seen here with self-seeders Euphorbia oblongata and the spiky leaves of Crocosmia ‘Lucifer’. Alliums are very hardy – down to minus 42C/minus 45F.
There was one Allium Christophii in this garden when we moved in 15 years ago. We now have around 80-100.
I particularly love this combination as both plants self-seeded themselves here. Allium Christophii knew it would look good with Rosa glauca.
Poppies
The common poppy or Papaver rhoeas is brilliantly colourful and so charmingly simple.
I’ve planted pretty lilac poppy seeds but this is what has come up. I think the lilac ones may have mixing with my reds…Common poppies (Papaver rhoeas) are hardy down to minus 50C/minus 60F.
Lychnis coronaria
Otherwise know as ‘rose campion’, this has cheery pink flowers and a nice grey felted foliage. Some of my lychnis has planted itself in a neat circle around a tree. It’s too close and isn’t particularly good for the tree, but I do admire the way it has synchronised itself.
This rose campion (Lychnis coronaria) may look sweetly shy and retiring, but give it an inch and it’ll take a mile. Lychnis coronaria is hardy to minus 37C/minus 35F.
Erigeron karvinskianus (Mexican daisies or ‘seaside daisies’)
I love seeing clouds of these growing out of walls and steps. Though I do have friends who don’t like them…you know who you are.
Seaside daisies with lady’s mantle, or – if we’re being posh – Erigeron karvinskianus with Alchemilla mollis. Erigeron is hardy to minus 23C/minus 10F.
Foxgloves
Where would a summer garden be without foxgloves? Here is a photo of the back border, which is actually full of plants which I planted. Except for the foxgloves, who kindly decided that I needed a bit more vertical interest.
The spires of foxgloves improve this border, most of which was actually planted. Although I keep digging up the Japanese anenomes – they’re spreaders, not self-seeders and would survive anything.
Foxgloves self seed themselves all round my garden. Some are white, some are pale pink and others have this deep rich pink. If you cut the central spike of flowers off once it is ‘over’, you’ll get more smaller spikes of flowers. Foxgloves are hardy to minus 34C/minus 30F.
Coriander
This is a surprise entry for this section. You are supposed to be able to grow coriander as a herb in Britain, provided you plant it late enough in the year to stop it bolting.
I have never managed to get more than a handful or two of the coriander leaves for the kitchen, but it flowers and self-seeds so beautifully that I think it probably works better as a flower for me.
Coriander grown from seed. It bolted but has since come back twice, and I rather love the flowers.
Self-seeders for foliage
My top self-seeders for foliage or greenery are:
Euphorbia oblongata
It’s unstoppable in its bid for world domination. Some of my other euphorbias, such as Euphorbia palustris, don’t self-seed or spread at all.
This Euphorbia oblongata knows that you should always plant yourself in threes….the spiky leaves between them are self-seeded Crocosmia, who also appear to have been reading about garden design and the importance of contrasting leaf shapes.
Mediterranean spurge (Euphorbia characias subs ‘Wulfenii’) is exceptionally long flowering – from early spring to mid-summer. It spreads vigorously around the garden and has a dramatic sculptural shape. Hardy to minus 17C/0F.
Alchemilla mollis
Lady’s mantle froths happily between pavers and pops up in beds. I have no idea where it came from. One day it wasn’t there, and then it was.
This Alchemilla mollis (also known as Lady’s mantle) has planted itself amongst some low-growing roses. Hardy to minus 37C/minus 35F.
Smyrnium perfoliatum
This is another vibrant early summer green that looks after itself. I bought three plants from Great Dixter over ten years ago, and now have two huge clumps. It’s exceptionally long-lasting as a cut flower and disappears completely around the end of June.
Smyrniums are becoming invasive in some parts, so it’s worth checking whether it’s invasive where you are. Search ‘is smyrnium invasive in (insert your area)?’
Smyrnium perfoliatum – a vigorous self-seeder for shade. It looks a bit like euphorbia and lasts a long time in a vase.
Self-seeding edibles
You can eat both marigolds and nasturtiums. I have known komatsuma, red sorrel and spinach to self-seed and be good to eat, and also rocket.
Parsley
Definitely my top self-seeding herb. It took a good year to get established from seed, and I was initially disappointed by its growth. But in its second year, it took off around the garden, where it serves as foliage, garnish and an ingredient for parsley sauce.
The parsley goes where it likes. Here it’s decided to share with a row of beetroot.
Self-seeding companion plants
It’s helpful if self-seeders can be useful. Marigold and nasturtiums are both valuable in the veg patch, where they help deter pests.
Marigolds
People can be snooty about these, and I do often pull them out, but their smell repels greenfly and blackfly. They also attract hoverflies which live on blackfly, so they are generally a good thing.
Marigolds in the rhubarb beds – they seem happy to grow anywhere in the garden, but I pull them out elsewhere. Marigolds are hardy to minus 45C/minus 50F.
Sculptural self-seeders
Sculptural plants are vital in any garden, and self-seeders can be wonderfully sculptural.
Angelica archangelica
It takes a couple of years to establish because it’s a biennial, but once it gets a cycle going, you’ll never have to give it another thought. Brilliant in May and June, collapses a bit after that, but you have to leave it or it won’t self-seed.
Angelica archangelica used as a temporary hat stand over a long lunch….
Crocosmia ‘Lucifer’
There was a patch of Crocosmia ‘Lucifer’ in this garden when we arrived fifteen years ago. It is now everywhere, but I do like it. Its seed-heads are wonderful, both in the vase and in the garden.
Crocosmia Lucifer with another sculptural self-seeding plant – verbena bonariensis.
Verbena bonariensis
This doesn’t self-seed quite as vigorously as I’d like, so I occasionally have to re-plant it. But it seems to need very little attention, and wanders about the garden, occasionally planting itself in a pot. It is hardy to minus 12C/10F.
Verbena bonariensis flowers on into the autumn as seen here at the amazing long border at No Name Nursery in Kent. It also looks good in frost in winter, so it has an exceptionally long season of interest. When you first plant Verbena bonariensis, plant lots. Then you’ll get self-seeders. If you just plant one or two plants, I’ve found the self-seeding results disappointing.
Sisyrinchium striatum (Pale yellow-eyed grass)
Sisyrinchium just appeared in the garden and it self-seeds readily. I think it adds some bright highlights to the border, but it can turn into a nuisance.
If it does, just pull it out. Most self-seeders are easy to pull out. And I always say that it’s easier to pull a plant out than it is to plant it.
This is so obliging that many people consider it a weed, but I love its sculptural creamy flowers.
The best self-seeding plants for shade
Angelica archangelica, foxgloves, smyrnium perfoliatum, lamium (dead nettle), primroses and Solomon’s seal all do well in shade. Solomon’s seal takes several years to get properly established, but I know have two generous clumps – from just one or two plants.
Primroses are such happy little self-seeders. They’re one of the first flowers as winter ends and are still pumping out blooms in early summer. Very easy care!
A trio of beautiful self-seeding plants that love the shade: Angelica archangelica, foxgloves and smyrnium perfoliatum.
Solomon’s seal now grows in two large clumps but it was not an overnight success. Patience is required, but not much effort. These plants were in a shady spot, and have gently self-seeded over around 10 years.
Cyclamen (Cyclamen hederifolium) and Sweet Woodruff (Galium odoratum) self-seeding together in a shady corner of my garden. The cyclamen have pretty white or pink flowers in late winter and is hardy down to minus 28C/minus 20F. The Sweet woodruff has tiny white flowers in spring. It is hardy down to minus 34C/minus 30F. A charming combination!
When NOT to allow self-seeding
Some plants do not make good self-seeders. In the veg bed, you won’t get any reasonable flavour out of anything that has self-sown from an F1 hybrid. That’s because an F1 hybrid has been specially created. Its seeds are usually disappointing.
However, heritage varieties of vegetable may self-seed, or it’s worth keeping their seed.
Similarly some garden flowers don’t come true from seed. My lavender self-seeds but I have been warned by the grower I bought it off that it won’t come true. He advised me to take cuttings rather than rely on self-seeders.
It’s also important to know what is invasive in your area. By ‘invasive’, I mean on an official list of plants that could do damage to your countryside if they escape into the wild. If plants grow too well in a particular climate or countryside, they can out-compete the local plants. And that means that local wildlife may not have sufficient habitat or food. This can be very expensive and difficult to clear up.
Every government has a listed of invasive plants. It’s usually illegal to sell or plant them in your area – yet the very same plants can be lovely garden plants in a different country or area.
So do an online search for ‘is (insert plant name) invasive in (insert your area or country)? Look for official government or university lists.
The one care tip you do need for self-seeders…
If you are an expert gardener, you can tell the difference between self-seeding plants you want and weeds at a fairly early stage. However, I’ve accepted that allowing such a vibrant mix of self-seeders means I also have more work with weeding, as the weeds do seem to get established early too. In this post, I’ve covered this issue with finding the balance between self-seeding vs weeds.
How and when you mulch can also affect which plants self-seed and how vigorously. Adding a layer of well rotted manure, garden compost or a wood chip mulch helps prevent weeds. It also breaks down to add nutrition to the soil.
However, anything that stops weeds will also stop self-seeders. I don’t find that mulching stops all self seeders, but it does stop some.
There are also lots of self-seeders in a wildflower meadow. Even if you only have a small patch of lawn, this post can help you create a mini meadow.
And read these posts if you want to save more money on your gardening or save money on garden design!
Shop my favourite gardening tools, books and products…
I’m often asked for recommendations, so I’ve put together lists of my favourite books, tools and gardening products on The Middlesized Garden Amazon store (Links to Amazon are affiliate, see disclosure).
For example, if you’re interested in self-seeding plants, you may also be thinking about making your garden more wildlife-friendly. I’ve done a post on What Makes A Good Wildlife Garden, and also put together some useful wildlife-friendly products like bird feeders, hedgehog homes and more on the Middlesized Garden’s Wildlife Friendly shopping list.
Pin to remember self-seeding plants:
And do join us every Sunday morning for more gardening ideas, tips and inspiration – see follow by email here.
Heidi says:
June 13, 2024 at 8:16 pm
Hi Alexandra, loved this post, my favourite self seeders in my garden are the globe thistle, snap dragons and wild violets. Also, currently getting strawberries everywhere! I think the birds are hinting at something!
Reply
Alexandra Campbell says:
June 15, 2024 at 7:49 am
I wish snap dragons self seeded here – they are so pretty!
Reply
Jeannie Meagher says:
June 8, 2024 at 1:50 pm
I have not had luck with a number of flowers you describe. Could I be doing something wrong? I’m in zone 9 also, but have hot/dry Sacramento summers.
Reply
Alexandra Campbell says:
June 13, 2024 at 12:39 pm
Hot and dry could certainly explain it, and also there’s quite a bit of variation from place to place. Some commenters have done better with plants than I have. It’s slightly tricky equating US and UK weather because we’re an 8 or 9 in winter, but probably only a 6 in summer. There are lots of plants that grow happily across all those zones, but they may not behave in exactly the same way.
Reply
Lynn Woods says:
August 11, 2023 at 11:54 am
Can you recommend a seed collection to prime a self-sustaining annual/perennial patch and when best to plant given we’re now into August? My ground area for this bed is about 8m x 4m. We’re not far from you, foot of N Downs escarpment so on chalk downwash, quite free draining, thanks
Reply
Alexandra Campbell says:
August 13, 2023 at 3:11 pm
I’m assuming you’re talking about self-seeders, but this varies so much from garden to garden and even year to year. Some years, one plant will self seed vigorously and another year it’ll be another. It’s an interesting question though – I’ve had a look at some of the ‘self-seeding collections’ and I’m not too impressed. I think I’d recommend putting together your own collection by buying individual packets of seeds of plants you like which are likely to self-seed, and then seeing which ones work best in your garden. All the plants in this post are worth trying – I hope that helps, with best wishes, Alexandra
Reply
Mishu says:
December 3, 2022 at 12:33 pm
You forgot Cosmos.
Reply
Alexandra Campbell says:
December 8, 2022 at 3:53 pm
Excellent suggestion, although I haven’t had much self seeding with them.
Reply
Gina says:
August 27, 2021 at 7:01 pm
Thank you.I find your posts and videos really helpful as a novice gardener.
Reply
Alexandra Campbell says:
August 30, 2021 at 5:08 pm
Thank you!
Reply
HENDRIKA BOSMAN says:
March 10, 2021 at 5:55 am
Do Salvia Sallyfun self seed?
Reply
Alexandra Campbell says:
March 10, 2021 at 3:41 pm
I’m sorry to say that I don’t know.
Reply
Emma says:
February 13, 2021 at 7:21 pm
So helpful, thank you – we have an awful problem with wild rabbits, but several of your suggestions I hope may be ‘rabbit proof’!
Our aquilegias do self seed… I love them and always think they’re like pretty ballerinas!
Such an interesting and helpful post, thank you.Reply
Jessie says:
June 16, 2018 at 2:29 pm
This is exactly the kind of gardening I can get on board with! Thanks for the comprehensive listing of plants.
Reply
Alexandra Campbell says:
June 18, 2018 at 1:56 pm
Thank you!
Reply
Evie Keith says:
June 15, 2018 at 7:42 am
These all flowers is so beautiful, I always want this kind of garden it looks so great.
Nice post keep it upReply
Alexandra Campbell says:
June 18, 2018 at 1:56 pm
Thank you!
Reply
Carol says:
June 10, 2018 at 2:22 pm
Thank you! I always look forward to your blog on Sunday!!
Reply
Alexandra Campbell says:
June 11, 2018 at 6:59 pm
Thank you!
Reply
Rhody says:
June 10, 2018 at 9:52 am
Your self seeding marigolds look an awful like Calendula. :-)
What Tagetes are they?
Cheers!Reply
Alexandra Campbell says:
June 11, 2018 at 7:02 pm
You’re right, they’re Calendula officinalis, or pot marigold, English marigold or common marigold…the tagetes are the Mexican marigold, African marigold…
Reply
Diana Hurter says:
June 10, 2018 at 9:06 am
Nothing witty or intellectual, just to say Thankyou. My daughter has just bought a house with her first proper garden so I am keeping a selection of your ideas for her, especially this one on self seeders. They will get her off to a flying start just from reading your bite sized chunks.
Reply
Alexandra Campbell says:
June 11, 2018 at 7:04 pm
Thank you! I hope she enjoys it.
Reply
Jan O'Donnell says:
June 10, 2018 at 8:31 am
I thoroughly enjoyed this post. You have given me so many planting ideas and I have clay soil too so that’s perfect! Your garden looks beautiful. Thank you !
Reply
Alexandra Campbell says:
June 11, 2018 at 7:06 pm
Thank you! The price of having alot of self-seeders is that I also have alot of weeds, but even they can be charming…up to a point. And I think we’re all getting a bit more relaxed about weeds as they can be so pretty too.
Reply
Catherine says:
June 10, 2018 at 6:46 am
Thank you for this, really interesting to know. I love the idea of letting the coriander flower!
Reply
Alexandra Campbell says:
June 11, 2018 at 7:04 pm
I wish I could claim that I had an ‘idea’ – it was sheer neglect but a little neglect is often quite good for a garden.
Reply