Growing Container Sweet Peas
The trend toward smaller gardens has become prevalent, and there is a growing desire to grow vertically and use containers adventurously. Have you thought that you do not have room for sweet peas? Plant breeders have come to your rescue! There are now wonderful single-colour container sweet peas, as well as varieties with splashes and stripes. Some will trail in profusion or form thick bushes that will fill a large pot or tight areas in your garden. This is very handy if you live in a windy spot. Some sweet peas will happily climb and not exceed 90 cm in height. So, yes, even if you only have an apartment balcony, you can grow sweet peas.
Consider growing a tumbling or trailing sweet pea. ‘Electric Blue’ (Lathyrus sativusazureas) is a deep azure blue with a pink throat. It’s very prolific and an early bloomer. The yellow species Lathyrusluteus will bloom a bit later. Last year mine were quite outstanding tumbling among dark blue cascading petunias.
Bushy sweet peas do just that: grow in bushes without support. The Villa Roma series bush sweet peas are single colours, with the easiest to find being ‘Scarlet’ and ‘Navy Blue’. ‘Cupid’ is an old, popular standby now available in many colours. The Minuet series is exciting, with splashes and speckles of colours. Minuet ‘Orange’ bloomed early in June last year and Minuet ‘Dark Blue Splash’ bloomed soon after. The Sprite series features lovely pastels; Sprite ‘Lavender’ has won many awards in England.
Intermediate sweet peas will climb 90 cm up a support in a nice large pot. Jet Set mix from Suttons Seeds will brighten up a bare spot in the garden or a pot on the deck with a brilliant show of single bright colours. ‘Theresa Maureen’ is a softer pink and lilac or cream, and ‘Turquoise’ is quite fabulous. All these sweet peas provide lovely bouquets for the house, but do not have the straight long stems of the Showbench varieties.
All sweet peas need rich, deep soil. They do not do well in shallow or hot soil, so invest in the biggest pots you can afford. This is a flower that needs consistently moist soil in pots with good drainage.
Container sweet peas do not require the pinching back technique used to create branching for other varieties. If you do it, you will severely delay bloom. Carefully tie tall plants to supports when there are six pairs of leaves. As they begin to bloom, deadhead regularly by snipping the flower off at the base of the stem. Do not pull off faded blooms, as this will cause damage to the entire plant.
In order to have June blooms, start seeds indoors in late March to early April, in 20 cm deep pots. Sowing in regular starting packs will result in roots curling up and around, and they will spend the rest of the summer trying to disentangle themselves. All peas like to germinate in cool soil. Decent light and a temperature no higher than 15 °C are required. A higher temperature will result in weak and stringy seedlings.
Depending on the weather, by mid-April your plants can be placed outside in a cold frame. Protect them from extremes; a shade cloth is essential to protect them from both frost and burning sunshine. Plant your sweet peas outside in May. They can tolerate quite a bit of frost, but when the weather gets too cold, bring your pot back inside for the duration of the cold period.
Following these guidelines will allow you to look forward to blooms in June. Then you will be cutting and cutting flowers throughout the summer. Enjoy!
To learn more about seed starting and the Calgary Horticultural Society, visit our website
www.calhort.org. Join us online for Think Spring! on February 11, 2023. Launch the gardening season with the Society.
Diana Calder, the “Sweet Pea Lady”
Calgary Horticultural Society