Diggers Sweet Pea Trials
As with all our vegetable trials, the only way to get decent information on varieties and how they perform is to grow them ourselves under the Australian sun.
Sweet Peas have been a constant in our seed catalogue since Diggers began listing cottage flowers more than 35 years ago. Australia had a preconception that our hot summers would not allow for warm season sowings, but our trials (conducted 10 years ago), highlighted that Sweet Peas can be sown twice a year, giving gardeners up to nine months of deliciously fragrant flowers.
As with all our vegetable trials, the only way to get decent information on varieties and how they perform is to grow them ourselves under the Australian sun. Through our close connection with the world-renowned garden plant breeder, Dr Keith Hammett in Auckland, we sourced 26 varieties and so set about growing a field of flowers. Many of these varieties are listed by Diggers today.
Initially we were curious to look at different flower colours, forms and levels of fragrance, but after speaking with Keith about different sowing timings and the potential to extend the flowering season by using successional sowings, we incorporated a few different sowing times to observe the impact on flowering.
Many of you will be aware of the folksy tradition of sowing your Sweet Peas on St Patricks' Day (March 17th), and while this is a great reminder, there is actually scope to sow Sweet Peas anytime in both autumn and spring.
In our trials we divided up the various sweet pea varieties into two groups based on the daylight hours required by each variety to initiate flowering. The two groups were classified thus:
Short-Day, or winter-flowering types that initiate flower in 10 hours of daylight (the Australian Early varieties are this type). These will flower in the short-day months either side of winter, with flowering times determined by the sowing month.
Long-Day, or spring/summer flowering types that initiate flower in 11-12 hours of daylight. These will flower through the warmer months whilst the day length remains greater than 11 hours in the late summer and extends beyond 11 hours in the late spring, with flowering times determined by the sowing month.
Sweet Peas sown in autumn grow slowly through the winter when the soil and air are cold; however, when sown in spring, rapidly get to size and flowering time.
And while they seem fragile and love the English weather, we also saw that beneath the Sweet Pea's delicate appearance lies a tough constitution that can withstand our southern summer heat, with our spring sown trials shaking off 42°C heat in early January to repeat flower happily through to February.
The below chart shows sweet pea flowering times.
Sweet peas for your area
Click on your zone below to see what sweet peas you can sow.
Tip: When viewing your sweet pea zone, use the filters on the side under Seeds to sow by month to help you plan!