How do you grow sweet peas perfectly?
Well, don’t be daunted. It’s not that difficult. But you will need the following: healthy, viable seed, good soil conditions, good air circulation, good pest protection and the right location.
Here are some valuable tips from sweet pea expert Renee Shepherd:
• Always buy fresh, healthy, viable seed from a reputable supplier. Seed does not stay viable forever and sometimes people have failures because the seed is old and dead.
• Start seed early. You can start them indoors in March in a good soil mix and transplant them into the garden soon after they get their first set of true leaves and are only a few inches high. Or, you can plant seed directly into the garden in April.
• Sweet pea seeds do not need a lot of heat to germinate. Unlike summer annuals, seed will sprout at 55 to 60 F. Germination can take up to three weeks.
• Pick the right varieties for the intended locations: short, cascading varieties for window boxes and hanging pots; dwarf “knee-highs” for containers; taller, climbing varieties for growing up trellises, fences or vertical supports.
• There are things you can do to speed germination. Soaking seed overnight is a popular method, but never leave seed in water longer than eight hours. A better way, says Shepherd, is to take a pair of nail clippers and nick each seed. “Do it just enough to split the skin. You don’t want to tear a hole, but just make a slit in the skin to allow water to be absorbed faster.”
• Sweet peas require well-drained soil, excellent air circulation and at least six hours of sunshine. Pick your location carefully. They thrive best where they get morning sun and light afternoon shade.
• Don’t transplant seedlings deeper in the garden than they were in their starter pots. Sweet peas like fertile, well-drained soil. You can add well-rotted compost to the soil when planting.
• Protect your seedlings from birds, snails and slugs. This is a golden rule. “Birds can be a major problem,” says Shepherd. “If you have seedlings one day and none the next, it is probably due to predatory birds. If I didn’t use netting to protect my seedlings, I would have no sweet peas at all,” she says. Slugs and snails can also be a problem.
• Pick flowers regularly to stop seed pods maturing. The more blossoms you pick, the more the plant will produce.
- Get the best out of your sweet peas
- How to grow sweetpeas: fill your garden with amazing scent
- Growing sweet peas as cut flowers? – give them a suitable support
- My take on the cordon method – using fewer canes
- What you need
- How to build
- How to plant your sweet peas
- Sweet pea supports
Get the best out of your sweet peas
Roger sows his sweet peas in autumn and spring (or in January on the kitchen window sill). He does not soak or sandpaper his seeds (it is unnecessary in a temperate climate). Once germinated, he keeps them cool (they will tolerate -5C), so that roots develop well and the shoots stay firm.
The autumn ones flower from late May/early June, for around two months. The spring-sown ones flower from mid August to the frosts. You can, however, get them to flower right through if you are canny and the weather is with you. Hot, dry weather shortens their lifespan, but if they have some shade in the hotter periods, or if it’s a cool summer, they can perform amazingly. Inadvertently, by growing mine beside the yew hedge, I have achieved this.
As to pinching out when a few inches high, this is unnecessary: it gives rise to premature side-shoot development, not necessarily a good thing. If you want more, you could take soft cuttings and, with a bit of bottom heat and a polybag, have extras in a few weeks.
In terms of how and where to train sweet peas, Roger and Ursula agree that the wigwam shapes generally advocated are not ideal. All the growth generated from the bottom ends up concentrated at a thin area at the top. Stakes with a coarse netting (such as pig), set into the ground in a circle (perhaps 500mm/20in wide and 1.2m/4ft high) are better; or use bushy twigs of hazel or birch as pea sticks – anything with long stubble to cling on to. Bamboo canes are smooth, so unless netting is added, it’s a chore giving them a leg-up.
As we are all nervous about irrigation this summer, I inquired about the amount of watering needed on my grotty soil. Roger describes “ring culture” in his excellent book: it is similar to planting in a deep, bottomless pot filled with fabulous soil, on top of soil. If grown in good soil, you can usually get away with no watering once your sweet peas are settled in. Roger never feeds or waters, he just mulches and manures, and has won top honours at the National Sweet Pea Show using this approach. If you do feed, high potash (tomato feeds) are best, as nitrogen feeds encourage too much top growth. If you must water, do so in the morning. Sweet peas can suffer from bud drop – the buds turn yellow before opening, then drop. This is caused by high temperature fluctuations, and watering in the evening with cold water can exacerbate this. Mildew, another glitch, is discouraged by dry air, and watering in the morning helps (as did growing mine by a hedge, providing shelter from drying winds).
Another tip is to deadhead just as the flower starts to go over. The idea is to stop the plant putting energy into seeding. If you jet off on holiday, you may get away with stripping off all setting pods and old blooms on your return and kick-starting them with a good feed and water.
Finally, the best bit of advice, I feel, is Roger’s recommendation for the semi grandiflora varieties bred in the last 10-15 years. These often have better scent than even the old grandifloras, their flowers are bigger and the stems are longer, and they do not have the large, coarse leaves of the modern Spencer varieties. Like the grandifloras they have flowers all down the plant, whereas the Spencers tend to have colour mainly at the top. I am looking for a navy and white flower, and Roger recommends ‘Albutt Blue’, a semi grandiflora type. He also sells other species of lathyrus and rates the recently discovered Belin pea, Lathyrus belinensis, from Turkey. It is a subtle red and yellow and does not get mildewed.
As for my own efforts, my sweet peas bloomed like mad for four months and were, I admit, a picture. You get pretty fast at the deadheading, and it is a pleasant job with all that wonderful scent.
Life readers can choose from a large variety of sweetpea seeds from Telegraph GardenShop from as little as £1.39. Visit gardenshop. telegraph.co.uk/sweetpeaseeds
Grow your own sweetly scented sweet peas. They’re deeply fragrant, easy to grow, and make beautiful cut flowers.
Sweet Peas are one of the most deeply scented cottage garden flowers — they’re also extremely easy to grow. The more you pick them, the more they produce flowers so they’re a great choice as a homegrown cut flower. Once picked, a bouquet can last up to a week and during that time the flowers sweeten the air and add natural beauty to any room. When the bouquet needs refreshing, more blossoms will have conveniently blossomed on the vine. If you’ve not grown them before, here are six tips to get you started.
1. Select your variety
There is a dazzling array of types and colors on the market and sometimes a huge percentage of a flower seed catalog can be just sweet peas! For me, I usually grow ones I find for free at one of our seed swaps since they all smell gorgeous. On Amazon you can get this great mix of 50 Heirloom Sweet Pea Seeds. Popular named varieties include:
- ‘Painted Lady’ Sweet Pea — this is the original variety and highly scented
- ‘Spencer Ruffled’ Sweet Pea — big ruffled flowers
- ‘Windsor’ Sweet Pea — deeply coloured blossoms recommended by Floret Flowers
Sweet pea roots will appreciate the deeper growing space of these toilet paper rolls
2. Sow sweet pea seeds
Either direct into the ground or in modules. You can do this in autumn or early winter and overwinter the small plants or do it in spring. Autumn sown plants will come into bloom a few weeks before spring sown ones but you do need to keep an eye on them over the winter. Make sure they’re under cover such as an unheated greenhouse, that their soil remains moist, and that they’re protected from rodents and slugs.
Sweet peas, like garden peas, will appreciate a deeper growing space. Although ordinary modules will do, sowing seeds into root trainers or toilet paper rolls encourages stronger growth. As far as soil is concerned, sweet peas, like all legumes, love rich fertile soil rich in humus and nitrogen.
Planting out sweet peas after the last frost
3. Transplant well after the last frost
They like a lot of nutrients so it wouldn’t hurt to put them in an area dug over with compost or well-rotted farmyard manure. These flowers are great in open ground like a garden or backyard but they also do extremely well in containers. Just ensure that wherever they are they’re just kept well watered. Tip: keep a container near the door so that you’re greeted with beautiful scent every time you leave and enter the house. What a great way to begin the day.
Fruit cage as a sweet pea support
4. Give the sweet pea plants support
These plants are climbers so a wigwam of canes, a lattice of willow, or even an old ladder or other garden art will give the plants the foundation to grow tall and strong. Keep them tied in using garden string or similar or they’ll flop all over the place.
The photo above is a clever idea I spotted on a garden tour. It’s such a clever way to use the netting around the edges of a fruit cage.
Bamboo canes are inexpensive supports for sweet peas
5. Pinch out shoots
If you pinch off the top growing tip of the plant when it’s young it encourages side shoots and a thicker and more blossom-abundant plant. If you don’t pinch shoots out the shoots the plants will still grow. They just might be a bit less full than their manicured relatives.
6. Keep picking
Remember that the more you pick, the more flowers you’ll have. Flowers quickly turn into seed pods and once they mature the plant decides it’s done it’s job. You might not get as many flowers after this point but you will be able to save the seed for next year.
How to grow sweetpeas: fill your garden with amazing scent
If you plant your sweetpea seeds now, you’ll get bigger plants with earlier blooms on healthier root systems.
Gardeners in the southern half of the country have always grown them this way but, with spring often arriving earlier, Philip says many of his northern customers are changing now doing the same, so I shall join them.
An alternative – one I’ve occasionally succumbed to – is to buy ready-grown plants. And Philip’s website caters for that as well. Varieties are ready to order now and will be dispatched in March/April to plant in your garden. Watch out for slugs, though.
Next, it’s online to indulge in some shopping. With a mouth-watering choice, it’s hard to plump for just a few. The dwarfs and sprites seem unappealing and modern, scentless varieties are out. Many of the heirloom or Old Fashioned varieties are too short-stemmed, so it’s the Spencers for me. Developed from a single variety discovered by one of Earl Spencer’s gardeners at Althorp in 1899, these are the showiest and prettiest on the plot.
Think of sweetpeas and you imagine ruffles of pastel hues, but the colours I love are darker: the purples (such as ‘Dark Passion’ from lathyrus.com), the maroons (‘Cupani’ and ‘Almost Black’ from johnsonssweetpeas.co.uk), and the magentas (the perennial Lathyrus latifolius is the most vibrant). There’s even a lime green (‘Limelight’, from sweetpea-seed.com).
Seed company Mr Fothergill’s runs an annual sweetpea competition at Capel Manor College in Hertfordshire. Two years ago, the breeder Sydney Harrod stole the show with ‘Valerie Harrod’, a huge pink Spencer with good scent and the biggest, pinkest flowers. Last year, his ‘Heaven Scent’, with unbeatable fragrance and pale salmon flowers, was the prize-winner. Both varieties are available from Mr Fothergill’s.
Bring your plants out into the garden in April, plant them in fertile, moisture-retentive soil and build a frame for them to climb. Mine hold fast to a row of tomato spirals that screens my seating area from the rest of the garden (and all the jobs I should be doing), where I can lounge and inhale their fragrance. Hazel wigwams and chicken-wire screens also make efficient supports. Make sure the soil is deep and fertile, and water your plants in well. Pinch out the leading shoots, nipping the stem above a set of leaves to develop strong plants, and pick each flower as it blooms. The more you pick, the more you’ll get.
Sweetpea top tips
For bigger, better plants, sow six seeds to a one-litre pot or use deep root trainers.
Don’t soak seeds; leave them on damp kitchen paper overnight, then nick any that have not swelled.
If you want sweetpeas in pots, grow Old Fashioned or Semi Dwarf varieties in as big a pot as possible. Feed well with seaweed or tomato fertiliser.
Sweetpeas like plenty of root room, moisture and a sunny spot.
Keep picking; as soon as seeds are produced, they’ll stop flowering.
Johnson’s Sweet Peas (01795 420 330; johnsonssweetpeas.co.uk)
Mr Fothergill’s (0845 371 0518; mr-fothergills.co.uk)
Owl’s Acre Sweet Peas (078 4000 8030; sweetpea-seed.com)
Roger Parsons Sweet Peas 01243 673770; rpsweetpeas.co.uk)
For information, see lathyrus.info and sweetpeas.org.uk
Sweet Peas in Pot
Don showed how easy it is to pot up some dwarf sweet peas for an impressive result. Sweet pea seeds are traditionally sown on St. Patrick’s Day (March 17), but in cool climates they can be sown in August and September. At this time of year sweet pea seedlings are also available in punnets.
- dwarf sweet pea seedlings, such as ‘Bijou’
- bamboo stakes (1.5m high)
- potting mix
- large pot
- plant ties
What to do
- Check that the pot has enough drainage holes in the bottom, and then fill it with a good quality potting mixture. (Tip: potting mix drops down with time, so compensate by adding a bit extra.) Place the stakes into the potting mix (at a slight angle) about 10cm from the edge of the pot (leaving enough room to plant the seedlings).
- Place the stakes about 5cm apart. Draw the stakes together at the top and tie with string. Plant one sweet pea seedling at the base of each stake. Attach the plants to the stakes with plant ties.
Dwarf sweet pea ‘Bijou’
Don used ‘Bijou’, a dwarf sweet pea that reaches a height of around 60cm. The colourful, fragrant flowers are as large as those of the tall varieties, and are borne on 20cm stems. ‘Bijou’ sweet peas are ideal for pots, window boxes or unstaked as a groundcover.
Caring for sweet peas To grow well, sweet peas need plenty of sun (at least six hours per day). Don’t use too much fertiliser (particularly high nitrogen fertiliser) or the plants will produce lush green leaves but very few flowers. Prolong the display by removing spent flowers. Do not overwater.
‘Bijou’ sweet peas are available from nurseries and garden centres, and cost around $4 per punnet. 1.5 metre bamboo stakes cost about $4.50 for a packet of 10.
Growing sweet peas as cut flowers? – give them a suitable support
Design for easy-to-make string cordon on cane frame
Tendrils of nearby plants can distort and bend flower stems
I love growing sweet peas on wigwams in an ornamental bed. Bamboo tripods and obelisks create height and structure in a flower bed and when festooned in fragrant sweet peas the effect is undeniably stunning.
However, when I started growing sweet peas in greater quantities for cut flowers I soon discovered the tripod or obelisk structure compromised the quality of the flowers.
Plants on an obselisk grow upwards and inwards, eventually converging at the top in a tangled mess. The ingenious tendrils of the sweet pea reach out and grab whatever they can for support. Where the tendrils wrap around a nearby flower spike, the stem can be bent and curled in the process.
I decided that I would start growing sweet peas in my vegetable patch, and that I needed to attempt to grow each plant more vertically and more widely spaced from its neighbours. It’s possible that it’s been done by others of course, but I developed my own take on a cordon method which I’ve set out below with useful photographs.
If you are trying to decide which varieties to grow for cut flowers you may also be interested to read my article on choosing the perfect bloom for you. Click here for my article on sweet pea varieties including some stunning pictures of my favourites for scent, colour, pattern and even the show bench.
A slection of choice sweet peas including ‘Nimbus’, ‘Night Sky’ and ‘Wiltshire Ripple’
My take on the cordon method – using fewer canes
It is easy to twist string around a sweet pea seedling – after which it will grow straight upwards
Professional growers and exhibitors for show tend to grow sweet peas as cordons – straight upwards and usually one plant per bamboo cane. The advantage of this is that each plant can be suitably spaced, won’t interfere with its neighbours and can easily be inspected for spent flowers. The cut flower grower’s enemy is flowers going to pod. Seed-set compromises flower productivity.
As I grow 50 or so plants a year I decided that investment in 50 new individual canes was beyond me, as was the ability to store so many canes.
My solution was to build a structure which used fewer canes and could support vertical strings up which the plants could be trained.
One major advantage of string is that it is very easy to train the plant upwards. Sweet peas are fairly robust, but can bend or even break if roughly handled. Tying stems to canes is fiddly, whereas it is very easy to gently twist a taught string around the growing stem.
What you need
To create each 2.4 metre long section of support frame you will need:
- 8 2.4 metre bamboo canes
- A big ball of gardening string
- Sharp knife or scissors to cut string.
This year, to support 50 plants, I built three 2.4 metre sections, connected together in one long line. This runs along a thin strip in between a line of asparagus and the edge of a raised bed and is an excellent use of a narrow space.
How to build
Bamboo tripods set a cane’s length apart
- Start by pushing three bamboo canes straight into the soil in a triangle.
- Gather the the canes together at the top to form a tall tripod. I start with a clove hitch over the top of one cane and then loop the string round each cane in turn a few times before tying the two ends of string back together.
- Lie a cane along the ground from the first tripod to gauge where to site the second tripod and repeat the steps above.
- Sandwich a cane horizontally between the crossing tops of the two tripods. If this is not firmly wedged in place, tie on with string.
- Secure a second cane horizontally just above ground level. This will need lashing to one of the vertical canes of each tripod. I used a method called square-lashing as this is very strong.
Square lashing is a good technique for securing a horizontal cane to a vertical one
- Take your spool of gardening string and place a pencil through the middle. Secure the end of the spool to the bottom cane at one end of the structure them, holding the pencil at both ends, run the string up and over the top horizontal cane, back to the bottom and continue unspooling to create a zig-zag of string along the length of the structure. Cut the string and secure at the end
- Don’t worry if the strings aren’t fully taught across the length of the structure. It’s difficult to achieve as canes are rarely perfectly straight and it can be difficult to keep the string tentioned. The sweet peas will climb regardless.
How to plant your sweet peas
- Prepare your soil by digging in some homemade compost along the line you want to plant. I added granules of chicken manure too to give the sweet peas extra oomph.
- Space your sweet peas 10-15cm apart along the base of the structure. Dig a deepish hole with a trowel, tease the sweet pea from its pot and plant securely.
- There is usually a gap between the sweet pea and the start of the strings. If this is the case I place a few twigs around the plants to support them until they reach the strings
- Once the sweet pea reaches the string it will probably start climbing up of it’s own accord. If they flop, grab the string just above the growing stem and twist it gently around.
- Once they get established, the sweet peas should need no further help and will scramble upwards giving you a long harvest period of strong straight stems.
Sweet pea ‘Price Edward’ growing strong and straight from a string cordon
Sweet pea supports
Last week Danny set about making a series of sweet pea supports for the kitchen garden – something for the sweet peas to scramble up when they’re planted out in a few weeks time, at the beginning of April.
He used coppiced hazel – 8 foot in length, choosing ones with lots of twiggy growth on that could be used to weave the structure together and create a better aesthetic overall. Bamboo and willow are good alternatives.
To create support that’s loosely in the shape of a wigwam, you’ll need eight lengths of hazel. Push each length into the ground in the shape of a circle, eight inches deep, a foot apart and 2 1/2 feet across each way. Firm them in around the base and pull them in together at the top and secure with twine.
Weave any twiggy bits in and out of one another, a loose woven effect that will give the sweet peas something extra to climb up.
Before you plant your sweetpeas out, wind a length of string around the base – roughly eight inches off the ground, something for them to cling to as they start their ascent.
Sweet peas can be prone to fungal infections leaving flowers and leaves mottled and flecked with white streaks. To prevent any spores from previous years affecting this year’s crop, Danny will mulch the beds with a thick six-inch layer of mushroom compost.
Sweet peas can withstand some frost, so this year we’ll be planting them out at the beginning of April and will give them a helping hand for the first couple of weeks with a liquid feed high in potassium – Tomorite or comfrey juice.
Plant them to the side of each stick (Danny plants to the right) rather than inside – one sweetpea per stick, eight in total.
As they begin to grow, tie them in by wrapping additional lengths around the support at intervals.
And water. Ideally, you want to water them in the morning, if possible, rather than later in the evening, as cold spells at this time of year can result in bud drop. Deadheading is the key to prolonged flowering, as well as picking. The more you pick, the more they’ll flower.
Danny will be hosting monthly garden workshops in the potting shed from the end of March focusing on seasonal jobs to do in the garden. As numbers are limited, you’ll need to ensure you book in advance. Please visit our events section for more information.