This guide comes courtesy of Florence Kennedy, the founder of Petalon, a flower delivery company that grows cut flowers on a regenerative flower farm in Cornwall.

She talked us through some growing basics so you can have colourful cut flowers in the garden and in your home.

For more top tips, check out Florence’s three cut flowers everyone should grow and follow @petalon_flowers and @bloomgardens_ on Instagram.

HOW TO PREP

Sun & Shelter

The first question to ask is: what is the sunlight situation? Ideally you want as much sunlight as possible. There aren’t many cut flowers that thrive in shade – though if that’s all you’ve got, aquilegias and foxgloves do nicely.

You also need shelter. Flowers don’t like to be too exposed to wind, which is tricky on a flower farm. But generally in built up areas like towns and cities, you’ll be alright because of neighbours’ fences and buildings. 

Using an existing border or bed

If you already have a flower bed in the ground or have a raised bed, all you need to do is make sure it is clear of other plants and completely free of weeds. If you’re lucky enough to have that, then simply rake the top layer of the soil so that it’s a fine, crumbly texture. Stick to raking lightly over the top layer, as the more you disrupt the soil, the more it can bring weed seeds to the surface to germinate and grow.

Raking it to a crumbly texture gives the seedlings an equal playing field to grow, so some aren’t getting submerged by clumps of soil or end up with rocks on them – it’ll give them equal access to the water and sunlight. If you don’t have a rake, don’t bother and just move on to the next step.

Add some compost on top of the soil, about 2cm deep, but you don’t have to be precise. And then add manure too. I use a sprinkle of either 6X Natural Fibrous Fertliser (which is a chicken fertiliser) or Marshalls Garden Organic Extra Fertiliser and Soil Improver – it’s expensive, but you only need a bit.

You can then sow the seeds directly into the border or plant young plants straight in. These can be seedlings you’ve grown in a greenhouse or on a window sill. Or they can be plug plants / seedlings you’ve bought at the garden centre or online.

Creating a new bed

If you’re making flower beds from scratch (for example, if you have a patch of grass you want to turn into a bed), start by covering it with a plastic sheet, tarp or anything that will block the light and some rain water. Make sure the cover is pegged or held down in some way. In a few weeks, everything underneath it will die. That makes it much easier to pull up all the weeds or grass roots. 

Keep it covered with your plastic sheet until you’re ready to get growing (ideally keep it covered over winter until spring). Then remove the cover and clear the ground of grass/weeds. 

Then lay cardboard across the whole area. That’s going to act as a weed suppressant for anything that’s still there. So, if it was a lawn, the cardboard is going to stop all the grass coming up again. Add a thick layer of compost and the manure we talked about in the EXISTING BORDER section. Pile the compost on top, about 15cm deep, and sprinkle in the manure.

It’s best not to sow seeds into this in the first year (though you can give it a try!). Instead, plant young plants, digging a hole in the top layer and breaking a little hole into the cardboard if you need to. The roots will find their way through.

Sowing seeds under cover vs direct sowing

If you’re sowing seeds indoors or in a greenhouse, this is called “sowing under cover”. Keeping seeds warm while they germinate and protecting them from pests and bad weather gives them the best start. Once they are strong seedlings, you can move them (transplant them) to a bigger pot or into the ground.

If you’re sowing seeds straight into the ground, this is called “sowing direct”.

You can do this in drills, which are straight lines you can mark out with a stick. Sowing in drills means you can instantly see which seedlings are flowers and which are weeds. And you can water the drill rather than the whole bed.

The nice thing about growing at home (not as a farm!) is that you don’t have to stick to straight lines. One idea is to make a hand print in the soil and then sow your seeds into the imprint, creating nice clusters of flowers that look more natural. Then you can stick a label in and know roughly what’s there.

Just remember the height of the flowers and don’t put a short plant next to a tall one, as the tall thing will block out the light. Put tall ones at the back of the bed and short things at the front.

WHAT TO GROW

Pick your colours

It’s very simple, but you should grow plants in the colours you like – not what’s on trend or what people recommend. You have to live with them in your garden and your house. My father-in-law can never get his head around some of our muted colours. He’s like, “But I want every colour there is in the most saturated version!”.

In the fields, we grow over 200 types of plants in every shade, but in my front garden, I just wanted blue. So I chose all blue flowers and it’s my favourite thing in the world.

Bear in mind the flowers should go together so they look good in a vase, but that’s very subjective. My best advice is to go for a tone, such as cool colours, warm colours, zesty colours. Or a limited palette, such as whites, pinks and purples.

Work out the timings

The next bit takes a bit of research, but I think it’s worth doing. You need to work out what flowers bloom when, because you don’t want everything up in June and then nothing for the rest of the year.

So in my blue patch, I have picked a flower that will be in bloom every month of the year – Iris reticulata in January, muscari in February, anemones in March and so on. These aren’t all classic cut flowers, but you get the idea – there’s always something happening in the garden and stems of things I can bring indoors.

[Download Bloom’s free PDF Flowering Times Calendar by clicking here. It’s a guide to which flowers are in bloom when.]

Grow annuals

For a cut flower patch, I would always recommend growing annuals. They are quick and easy. If you have other planters or borders, you’re probably growing some perennials, shrubs, grasses and bulbs, so you can pick from around the garden too, and focus your patch on annuals.

Annuals live and die in one year and generally split into two groups: cold hardy (these can handle frost) and tender (these cannot survive frost).

Tender annuals

Start sowing tender annuals in March. They’re quick to germinate and super easy to grow. If you’ve never sown seeds before, go straight in with the tender annuals. They are so fun and colourful. 

Sow them under cover and when they are strong seedlings, transplant them to your cut flower patch outside.

Tender annuals such as cosmos and zinnias are known as “cut and come again” plants, which means more flowers will grow back once you’ve cut a flowering stem.

Tender annuals for cut flowers

Sunflowers (Helianthus) Who doesn’t love a sunflower? There are so many cool colours now. I like the branching varieties [such as ‘Ruby Eclipse’] as they have smaller heads.

You can dictate how big your plant is going to be by how close together you plant it next to something else: the closer they are, the smaller they will be. If you have a few sunflower plants, keep them close together, about 30cm apart. With the branching ones, pinch out the tip (this means cutting off the very top of the plant) when they’re about 40cm tall. This will give you nice-sized heads rather than the whopping great big ones.

Zinnias These come in so many cool colours now. My favourite is Zinnia haageana ‘Jazzy Mixture’, sometimes called ‘Persian Carpet’. You get flowers in an amazing mix of colours: browns and yellows and burgundy. They’re unusual, but they go with everything. Sow these direct as they dislike being moved around.

Celosia These look like mini brains and are not everyone’s vibe. If you pick them early they look like coral reef fans.

Cosmos Everyone loves cosmos and my absolute favourite is ‘Apricotta’. It’s a dusty apricot colour with an almost violet sheen on it. It’s amazing. They grow quite tall and they’re nice to have at the back of a bed to create movement.

Hardy annuals

The amazing thing about these is you can sow the seeds somewhere protected under cover (indoors or in a greenhouse) in winter (rather than spring). And then plant out the young plants during a special window, which is 6–8 weeks before you expect the last frost in your area. 

For us in Cornwall, our last frost is about mid-April. They get planted outside when it’s still cold and they hunker down, and then you’re rewarded with earlier blooms than seeds sown in spring. 

With these, you can do what’s called succession sowing of the same seeds. For example, we sow hardy cornflowers in January and plant out early March. And we sow another batch in March and plant out in May. When some cornflowers are done, you get the next batch flowering. It also means if one batch doesn’t make it, you have more to fall back on.

You can also direct sow hardy annuals – sow them in the ground at the end of summer or early autumn when there’s still some warmth in the ground. 

Some of my favourites are technically perennials, but for cut-flower growing, we treat them as annuals.

Hardy annuals for cut flowers

Cornflowers (Centaurea cyanus) So many patterns and colours to choose from. They are the sweetest little buttons. ’Classic Magic’ gives you a range of beautiful purple shades.

Ornamental cress (Lepidium sativum) This is a perfect foliage and filler in arrangements, bringing lots of height, movement and delicacy. 

Field pennycress ‘Green Dragon’ (Thlaspi arvense) ‘Green Dragon’ pennycress is another amazing foliage filler with a lot of character.

Feverfew (Tanacetum parthenium) This is another great foliage filler.

Larkspur (Delphinium) This has lovely tall spires, but will need some support when it grows tall. You can use cut flower patch netting or make your own with twine.

Nigella The great thing with nigella is when the flowers finish you get the seed pods, which give fantastic texture to your bouquets and can be dried for winter. We do several successions of this, like we do with the cornflowers. It prefers to be sown direct in spring, as it doesn’t like its roots to be disturbed. Be aware: this self sows, so will come back without you doing a thing for a few years.

Calendula There are so many sunny shades to choose from, “Snow Princess” is a beautiful buttery soft yellow.

Poppies (Papaver) Probably our most popular flower for spring, Poppies are not for the faint of heart. They are tricky to germinate and can be a very fussy flower, so I’d maybe attempt these once you’ve got your training wheels off. 

Snapgragons (Antirrhinum) Hailed as one of the easiest annuals to grow, we have always found them really tricky! I think they actually prefer to be ignored and seem to do much better when left to their own devices. 

Sweet Williams (Dianthus barbatus) I know these are kind of old fashioned, but you can get some really lovely colours and they smell amazing. Sweet Williams are cut-and-come-again plants. Look out for a really unusual black one called ‘Sooty’. 

Scabiosa atropurpurea These flower for such a long time. And if you sow them in succession, you’ll have flowers for months and months. They are not completely hardy, but can take cold to about 0ºC.

Saponaria officinalis This is a great filler flower. It gives an airy, wildflower feel.

Phacelia tanacetifolia The bees love this! It has a smokey lilac colour and the shape is so unusual. It’s a great filler in a vase. It smells delicious, too. Direct sow this in spring.

And a couple of perennials

We don’t grow many perennial plants at Petalon right now, but it’s good to add a couple.

Dahlias I think dahlias are so fun. And there’s no harm in putting a tuber in and seeing how it goes. Even if it doesn’t grow well, you’ll still get a few stems, and unless you live somewhere very cold, it will come back the following year. It’s nice to have one bougie dahlia, like ‘Labyrinth’, or one of the dinner plate varieties for focal flowers.

Apple mint (Mentha suaveolens) I love flowering mint! We love to add scent to our bouquets and use lots of this. Be warned, mint spreads, so only plant it in a self-contained pot.

Scented-leaf pelargoniums The unusual shape of the leaf and the powerful scent of these geraniums is wonderful. They are tender perennials, so it’s best to grow in a pot so that you can move it inside as a winter houseplant. 

AFTERCARE

Pests

Everyone’s pests are different, so it’s hard to advise on every eventuality, but you do need to protect seeds and young plants growing outside. 

If you’re direct sowing, cover the seeds with a fine mesh sheet. This will stop the birds eating them before they’ve had a chance to germinate and grow. You can buy hoops and horticultural mesh netting to cover your seeds. You can do the same with young plants – the hoops keep the netting elevated above your seedlings.

Some people might be comfortable using a pet-friendly, organic slug and snail repellant. Some people will prefer copper rings or coming out each evening to pick the creatures off.

Deadheading

Deadhead all cut-and-come-again plants including cosmos and zinnias, especially if it’s been raining, as they can get brown and mushy. Deadheading means cutting off dead flowerheads before they produce seed. 

Feeding

We soak all of our young plants in a seaweed solution before we plant them out. That’s probably not necessary for home growers. But if you are planting out your seedlings and young plants, drop a bit of compost or manure into the hole before you plant them (I’ve listed a couple of manure fertiliser options in the HOW TO PREP section).

A note on arranging

Having different flower shapes – like spires, saucers, pompoms – brings a lot of interest and drama to a vase. But to be honest, I’m a florist and I would rarely make a full arrangement for my house. I use a vase with a narrow neck, because it makes it easy to make a few stems look great. 

Look around the garden or even out in the wider landscape for things you can add to your vase. This gives you more to arrange with alongside the flowers you’ve grown. It will bring different shapes and heights, so you have bits poking up or trailing down from the vase.

Look for floaty grasses for height, a sweet pea tendril for some movement, or a few stems of Nepeta (cat mint) for scent. I think that collecting odd bits from here and there to go with your annuals is the joy of bringing flowers into the house.