Oh Sweet Pea – the Queen of Annuals – with scent and colour divine

In the world of today the sweet pea has become a favourite flower amongst gardeners, florists and just about anyone else who likes the charm of fresh cut flowers in their homes or gardens. Their rich, sweet scent, large variety of colours and common place abundance have given them a high status in consumer markets as they have consistently been voted as one of top types of flower for growing at home and for using in cut arrangements.

History of the sweet pea

Their popularity goes back along way and the flower has seen many mutations during its spread around the globe. The sweet pea was originally a native of Sicily and southern Italy and in the 17th century was only to be found in Southern Europe. In those days the flower was very small and had a very powerful fragrance which made it a popular gift amongst the locals. It was a climbing vine that could grow to be about 6 - 8 feet tall and would be covered in bright purple and maroon flowers. The stories tell us that the sweet pea made its way into modern horticulture when, in 1699, a Sicilian monk by the name of Franciscus Cupani sent some seeds to a doctor he knew in Enfield, England and a highly respected botanist - Caspar Commelin - living in Amsterdam.

The sweet peas natural attractiveness ensured it was well received and it was studied intensely in the early 1700’s. Just 30 years later there were already mutations in colour as horticulturalists began to experiment with deliberate cross breeding of the natural variations. Since that time, the number of species has grown enormously with variations in colour, scent and growth type.

The original is now usually known as the Cupani or Cupani Original. There are also other early writings which refer to pink and white varieties that came from Ceylon and blue toned South American varieties called Matucana, however these seem to be derived from cultivated plants and probably first appeared in the 1850’s and 1920’s respectively.

Throughout the early 1900’s the demand for sweet peas grew dramatically as the quality of the flower was improved by new methods of cultivation. In California, huge areas of land were used to grow the flowers and the seeds were mostly sent to Europe – about 450 tonnes of them per year! Eventually this lead to the formation of the National Sweet Pea Society in Britain and ever since the flower has been a regular favourite at flower shows around the country as it becomes ever more refined.

The sweet pea family

Kingdom: Plantae (Plants)
Division: Magnoliophyta (Flowering plants)
Class: Magnoliopsida (Dicotyledons)
Order: Fabales
Family: Fabaceae (Legumes)
Subfamily: Faboideae
Genus: Lathyrus
Species: There are over 160 different species

All sweet peas belong to the genus Lathyrus, with the common sweet pea known as Lathyrus odoratus. One may not think it to look at them, but belonging to the pulse family they are relatives to the chickpea and green pea. Don’t go trying to eat them though – they can be very poisonous in sufficient quantities.

Generally there are three main types of sweet pea, the dwarf, the summer flowering and the winter flowing (always grown in controlled environments for cut flowers). And as well as the mutations in colour and scent many types now grow in low bushes instead of on the vine.

Growing sweet peas

There are a huge amount of sweet peas that are grown commercially both for use in the cut flower industry and because it a honey plant and the source of an essential oil used in perfumery. However it is incredibly popular amongst home gardeners too, as it is very easy to cultivate.

Sweet peas are an annual that are grown from seeds and grow best in cooler, mild climates. They like to grow in a rich, well drained soil and they grow better if they are planted in a different, but always sunny, patch each year. They are normally planted at the very end of winter or early spring and should bloom throughout spring and summer.

Once the planting location has been chosen, the soil has been dug over, and compost added if necessary, the seeds can be planted. Sweet pea seeds are very small and often wrinkled in appearance, weighing in at about a tenth of a gram. An expert can use the look of the seed to predict what colour the flowers will be.

Usually the seeds are soaked in water the night before they are planted;1 this helps them to germinate faster. The seeds should be planted about an inch under ground and about 3 inches apart. Once that’s done they will need a good thorough watering. It will normally take about 3 weeks for them to begin to sprout, during this period they shouldn’t be given to much water.

The growing sprouts are very attractive to all sorts of animals, from pigeons to mice to slugs, so you should make sure that you have a method in place – such a net cover – to prevent your entire bed from being eaten in one sitting. As they get older they are also prone to some pests such as aphids as well as certain bacterial diseases.

If they are of the climbing variety, they will need some type of trellis for support (bare in mind that some species can grow up to 10 feet tall), otherwise they can be left to their own devices, however the bush type may need to be thinned out when each plant reaches about 4 inches high. Once they begin to flower they should do so for the entire season if taken care of properly – this means lots of water – otherwise the flowers will soon fade away and probably won’t come back. Good mulching will help a lot, especially in warmer climates. They benefit from dead heading and there is a wealth of other cultivation techniques to make them produce better flowers.2

Once the flowers are cut they do not usually last long at all – perhaps 2 days at most – unless they are specially treated. The plants tend to produce more flowers when they are slightly root bound, this makes them excellent choices for pots, window boxes and hanging baskets.

Sweet pea titbits

  • Much of the early genetics work at Cambridge University was done with sweet peas as the guinea pig.*
  • Despite the magnificent range of sweet pea colours you’ll never find a yellow one. Early expectations of being able to breed a yellow sweet pea by conventional means were already fading rapidly by 1915. The search is still going on today – yellow variants have been produced but they have no scent.
  • Sweet pea flowers naturally self pollinate while still in bud. This means that the colour and scent of the flowers are essentially redundant as the flower has no need to attract insects or other pollinators.
  • The name "sweet pea" is believed to have first been used by Keats who studied at Enfield. He wrote:

    Here are Sweet Peas on tiptoe for a flight,
    With wings of gentle flush or delicate white,
    And taper fingers catching at all things
    To bind them all about with tiny wings.

  1. heyoka says rather than soaking, you can take a small nick out of the seed casing.
  2. and don't let them produce seed pods, or they'll stop with the flowers.


  • Owl’s Acre Sweet Peas - http://www.lathyrus.com
  • The garden helper - http://www.thegardenhelper.com/Lathyrus.htm
  • Bartleby.com - http://www.bartleby.com/65/sw/sweetpea.html
  • Garden guides - http://www.gardenguides.com/flowers/annuals/sweetpea.htm
  • Sweet pea classification - http://encyclopedia.thefreedictionary.com/Lathyrus