April is traditionally Sweet Pea planting month in South Africa

ISweet Peas Dwarf Mix. Picture courtesy Nu-leaf NurserySweet Peas Dwarf Mix. Picture courtesy Nu-leaf Nurseryn this article you will learn about the romantic history of sweet peas, and everything you need to know about growing and caring for these fragrant winter and spring flowering favourites. Read more below.

Perhaps because of their long history sweet peas could be called “old fashioned”, but gardeners and breeders alike know they are as lovely and rewarding as ever, and new, ever more enchanting and  fragrant cultivars are continually released.

Sweet peas, also called “Pronkertjies”, are lovely cut flowers, spreading their heady scent throughout the garden and home, and the more you pick them, the more they bloom. They are available in almost every conceivable colour, except for yellow and are so easy to grow they are suitable for children’s gardens.  All they need to flourish is full sun, rich soil, and regular feeding and watering. It’s no wonder people have been romancing the sweet pea for hundreds of years.

Sweet peas reside in the genus Lathyrus in the legume family Fabaceae, and are native to the eastern Mediterranean, including southern Italy, the Aegean Island region, Sicily, and Cyprus. A Sicilian monk, Francesco Cupani (1657 – 1710), who was also a renowned naturalist and botanist, was so enamoured with the sweet aroma and simple but beautiful blooms of wild sweet peas he carefully documented the plant, and thus became the first known botanist to do so.

Sweet peas. Picture Sebastian Crump from flickrSweet peas. Picture Sebastian Crump from flickrHe probably also gave it the scientific name Lathyrus odoratus, as in 1692 he became the first Director of the botanic garden at Misilmeri, where the plants were classified in a system of taxonomy called “binary nomenclature”, or simply put, a two-term naming system given to all species of living things, with each name composed of two parts, both of which use Latin grammatical forms, although they can also be based on words from other languages. This system was later made standard by Carl Linnaeus, who is called the "father of modern taxonomy".  A good example of this system is the Sweet Pea.  Its scientific name “Lathyrus odorata” derives from the Greek word “lathyros” for pea or pulse, and the Latin word “odoratus” which means fragrant.

Cupani’s romance with the sweet pea did not end there as he recognised the breeding potential of this fragrant bloom and started growing sweet peas in the gardens for breeding purposes. Because his work put him in contact with many other famous botanists, like all keen gardeners, he sent seeds to plant collectors and botanical institutions around the world, including those in England and Holland.  One recipient, a botanist at a medical school in Amsterdam later published a paper on sweet peas, which included the very first botanical illustration of Lathyrus odoratus. To this day, what is called the “Cupani” Sweet Pea, with its heady fragrance and beautiful blooms, remains a popular garden variety.

Click here to see Google images of the ‘Cupani’ sweet pea.

Cupani also documented one called “Painted Lady”, which also remains one of the very best heirloom types, and the most highly scented sweet pea you can grow. Its bi-coloured pale pink and darker pink-flowers also appear earlier than other sweet pea varieties.

Click here to see Google images of ‘Painted Lady’

Some of the seed sent to Britain in 1699 went to a man called Dr Robert Uvedale (1642–1722), of Enfield, in Middlesex, but from these only a few new forms of sweet pea appeared. In 1793 the seedsman John Mason, of Fleet Street in London described five varieties, including white and scarlet types, a black-flowered form that was probably maroon, and a purple variety that was most likely from the original Cupani wild type introduced from Sicily in 1699 by Francis Cupani.

The romance between plant breeders and the sweet pea continued, and a Scottish nurseryman, Henry Eckford (1823 –1905) created many of the sweet peas we still grow today. He worked as a gardener until 1888, then, at the age of 65 he set up his own nursery at Wem, in Shropshire, to dedicate the rest of his life to improving and expanding the limited selection of sweet peas then available. His work resulted in greatly increased flower size and a much larger variety of flower colours. He perfected the breeding of his “Grandiflora” sweet peas, which were such a great improvement over previous varieties they turned the sweet pea from a relatively unknown wildflower to one of the most popular flowers of the Victorian era. As reward for his hard work, Eckford was granted a Victoria Medal of Honour by the Royal Horticultural Society, and as they say, the rest is history.

By today’s standards, Eckfords Grandiflora group of sweet peas may be considered to have relatively small flowers and short stems with three, sometimes four flowers to a stem, but these heirloom seeds are still sought after for their flowers and wonderful, strong scent.

Click here to see Google images of Henry Eckford’s sweet peas. 

The mutation of truly large sweet pea flowers occurred in the 1900’s at Althorp House in West Northamptonshire, where gardener Silas Cole grew and bred many of Henry Eckford's grandiflora varieties. To his delight, one of his plants threw up huge, bright pink flowers with gorgeous, wavy petals, and most importantly, still retained its lovely scent. He named it “Countess Spencer” and exhibited it at the National Sweet Pea Society's first show in 1901, at the Royal Aquarium in Westminster, London, where it created quite a stir. The Royal Aquarium and Winter Garden was sadly demolished in 1903.

Everyone went mad for this frilly, flamboyant, scented flower and even more work went into expanding the range of the so-called “Spencer” sweet pea types that they gradually became available in almost every colour but yellow, and many of these varieties are still grown today.

Click here to see Google images of Spencer sweet peas.

The world famous Unwins Seeds Company was formed by William Unwin in 1903 by first selling sweet pea seeds, and in 1914 his son Charles, who also had an interest in sweet peas, joined the business. William and Charles bred lots of these new varieties, and had also found a frilly form which William named “Gladys Unwin” which was widely used as a cut flower for the Covent Garden market, and eventually this sweet pea became the basis of Unwin's Seed Company. 'Gladys Unwin' proved to be more stable than Cole's 'Countess Spencer', so William released and marketed it as “Countess Spencer Improved” and she was a great success.

Unwins Seeds was bought by Westland Horticulture of Dungannon, County Tyrone in August 2004, but Unwin sweet peas remain popular with gardeners and are still available today.

Click here to see Google images of them.

Henry Eckford's breakthrough also inspired many other hybridists who moved on to what was called "stripes" and "flakes".  A stripe sweet pea had a darker edge colour to the rest of the petal, called a "picotée edge".  A flake had no picotée edge, but rather displayed ‘flaky’ colouring on both sides of each petal. These were all the rage in the nineteen twenties and thirties and are having a big revival now in many parts of the world, with varieties called “Ripple” sweet peas, with interesting names like, 'Wiltshire Ripple', 'Blue Ripple', and the almost-black, 'Nimbus'.

Click here to see Google images of the stunning 'Ripple' Sweet Peas.

Grandiflora sweet peas can be broadly split into two groups, the ‘Antique Heirlooms’ are the older heritage varieties, many dating back to the turn of the 19th century, and the ‘Modern Grandifloras’ with their large flowers, and lots of them, coupled with the long stems of the Spencer types, and the bonus of the fantastic scent from the original 'Cupani' sweet pea, it is impossible not to fall in love with sweet peas!

In the past few decades, there have also been sweet pea developments, regarding the size of the plants themselves, and besides the traditional climbers, we have dwarf varieties for containers, and medium-sized ‘Knee-high’ climbers to make hedges, and we even have early and late flowering types.

Today sweet peas are available in a mind-blowing selection of single and mixed colours ranging from almost black to pink, blue, lilac, purple, red, white, and all the shades in-between. In fact they are available in almost every conceivable colour, except for the ever elusive yellow.

Sweet Pea Bouquet. Image by utroja0 from PixabaySweet Pea Bouquet. Image by utroja0 from PixabayIn the Garden & Home:

Once you have grown sweet peas successfully in the garden there’s no going back, and you’re sure to save space for them every season. They are so easy even children love growing them, and the seeds are large enough for even the tiniest of fingers to handle. Ensure that children are supervised when planting the seeds as they are poisonous.

The biggest joy of growing sweet peas is picking large bunches to fill your home with their delightful scent and vibrant colours. They only last about five days in the vase, but are well worth arranging in uncomplicated bouquets.

Sweet peas are available as climbers which can be grown anywhere they have some support, knee-high’s are great in the middle of a winter and spring flower border, and dwarf varieties are great border plants and fabulous in pots, window boxes and hanging baskets, so there’s no excuse not to have some sweet peas, even in the smallest of gardens.

Sweet peas go well with many winter and spring flowering annuals and bulbs, the choice is yours, so be inspired to create your very own little piece of paradise.

Cultivation/Propagation:

Sweet peas grow well throughout South Africa, and are generally pretty hardy to frost. However, in extremely cold regions, and where the weather remains cool during spring and early summer, the late flowering varieties are sown, or trays of seedling are planted out in spring to flower in early summer. In the winter rainfall regions they are wonderful water-wise additions to the winter and spring garden. In areas with hot or humid summers, the key to growing sweet peas is to purchase a variety that will bloom before the summer heat sets in. Look out for varieties that say ‘early flowering’ or ‘early multiflora’.

Picture courtesy Sebastian Crump from flickrPicture courtesy Sebastian Crump from flickrSweet peas are easy to grow but it is good to remember that they are hungry plants that love rich soil with regular feeding, and as much sun as they can get. They also look best if planted in a spot protected from strong winds. The seed is generally sown in autumn, and is best sown directly into garden beds when the temperatures are between 13 and 20°C, but trays of seedlings can also be planted out.

Prepare trenches for the climbing varieties a week or two before planting or sowing by digging a trench about 50 to 60cm deep and 30cm wide, adding lots of compost and well-rotted manure to the soil. Also dig in organic 2:3:2, and bone meal or superphosphate; and if your soil is acid add a light dressing of agricultural lime.  If you have some wood ash (not charcoal), this is also excellent dug into the soil.  Put the soil mixture back into the trench, forming a long mound in which to sow your seeds. Water the trench well and allow it to settle before planting. Dwarf sweet peas need not be planted in trenches, but prepare your soil, and care for them as for the climbing varieties.

Sweet peas also grow well in pots as long as the soil is rich and well-drained. Remember that potted plants will require more regular watering than those growing in the ground, so check the pots often, and don’t forget to feed them regularly, or use a slow release fertiliser in the soil at planting time.  

Climbers need support and the support must be erected before sowing or planting. Investing in a sweet pea net or fairly fine netting of sorts which can easily be attached to a row of posts is really worthwhile. These nets can usually be stored for use next season, or they can be used in summer to grow climbing green beans. Sweet peas growing up netting will easily attach with their tendrils, reducing the time spent having to tie them up.  You can also make a wigwam using four tall dowel rods, or bamboo, and tie the netting around them. Even long branches trimmed off of trees would work.

To speed up germination soak the seed overnight in tepid water before sowing. Many gardeners have better germination rates if they lightly nick the seeds with nail clippers before soaking. Plant at the depth indicated on the seed packet (usually about 2 to 3cm deep) and 10 to 15cm apart for the climbing varieties, or 15 to 20cm apart for the bushy ones. This plant needs ‘elbow room’ for proper air circulation and to ensure the roots don’t get too crowded, so check the seed packet to ensure that your spacing is correct.

If you’re planting climbers around a structure like an obelisk or tee-pee, plant 2 seeds about 5cm apart next to each stake, and when the shoots are big enough, remove the weaker of the 2 seedlings. 

Water thoroughly after sowing, keeping the soil moist but not soggy, and the seeds will germinate within a week or two, depending on the soil temperature, and will take 16 to 20 weeks to flower, depending on the variety.

To encourage bushy growth, pinch back your plants when they are about 15cm tall. Keep up the pinching throughout the season when you see vines looking a little leggy, or if you want to increase the bushiness of your dwarf plants. Pinching back the plant is easy, just pinch off the stem tip and new leaf growth right above an established set of leaves, using clean shears or the tips of your fingernails. Deadhead faded flowers and cut away any emerging seed pods regularly to prolong blooming and keep your plants from going to seed early.

Another way to prolong the blooming season is to fertilise regularly and to keep on picking the blooms – the more you pick, the more they bloom! Feed every 2 weeks during the growing season with a balanced, water-soluble fertiliser for flowering plants.

Sweet Pea PurpleSweet Pea Purple

Established sweet pea plants will go to seed more quickly if the soil is allowed to dry out completely, so water deeply in the morning once or twice a week, or as needed, depending on your local climate and weather conditions.

Seed can easily be saved from the previous year's plants, although not all varieties reproduce exact replicas of the parent. Remove the mature seed pods from the plants and put them in a paper bag to dry out. Once they are dry the pods can be popped open to release the seeds, and stored in a cool, dry place.

Problems, Pests & Diseases:

Sweet peas do not suffer from serious pests and diseases, and because they are grown in the cooler months, insect activity is at a minimum. However, as the weather warms up in spring watch out for common summer pests like aphids, leaf-miners, and red spider mites, which can be treated with an insecticidal soap or neem oil. Early spring rains will bring out the snails and slugs, so keep an eye out for them too.

If plants are incorrectly spaced, or don’t get enough sun, mildew can be a problem. Address this issue by thinning the plants out and applying a fungicide.

Warning:

The seeds of sweet peas are mildly poisonous, containing lathyrogens that, if ingested in large quantities can cause a condition called Lathyrus. Symptoms of Lathyrus are paralysis, laboured breathing, and convulsions. Always supervise children and pets in the garden, discouraging them from chewing on plants.