How to grow Great Sweet Peas

Author: JM   Date Posted:25 February 2018 

Enjoy the sweet, spicy fragrance of Sweet Peas

How to grow Great Sweet Peas main image How to grow Great Sweet Peas image

Our desire to grow particular plants in our gardens is often motivated by sentiment, it certainly is with me when it comes to growing Sweet Peas. I  was given my first bunch of Sweet Peas by Mrs Flanagan , my  kindly grade one school teacher,  who had observed  my interest in gardening and continued to nurture it with similar acts throughout my first year at school. I was fortunate also in being invited each spring into our elderly neighbours garden where my mother and  I would stand in awe, breathing in the intoxicating fragrance of a wall of Sweet Peas growing on her tennis court fence.  The scent of Sweet Peas has remained  evocative of my childhood  ever since.

Each year as I am planting our own display, on rather more modest trellises,  I am transported back to that simple time.


In our climate of extremes it has been a bit of trial and error to discover the best time to grow Sweet Peas but for most of the country sowing time is traditionally St Patricks day ( March 17). Sweet Peas like to establish their root system over an extended cool period which in  all but the southern mountain areas, like ours, is winter. As long as there are long stretches of open sunny weather over the winter months Sweet Peas are quite tolerant of a few frosts.

The original Sweet Pea is said to have originated in Sicily where summers are hot but winters cool and  mild  and as Sicily is basically one big chunk of limestone this also accounts for the Sweet Peas' preference for alkaline soil.

Both of these points are key to success with these sweetly scented annuals and both are the exact opposite of our own  prevailing conditions but this has not deterred us.


For our March sown crop we choose the sunniest north facing site  we have which conveniently is in our kitchen garden where the house provides wind protection on the west and south sides. The trellis is erected in the middle of the hedge enclosed garden so as to maximize the winter sun it receives.

Our spring sown crop is grown here also but closer to the wall of the house where the afternoon shade it provides keep the roots cool and the flowers protected .



It's hard to find the time for the thorough soil preparation which is essential to ensure  success but somehow we  manage to fit it in -  maybe not every year but certainly every second year. It is really is the secret to growing  strong deeply rooted plants that will produce long flower stems with good floret count.  Whilst the Victorian idea of double digging a trench for just about every crop every season has been all but abandoned when it comes to Sweet Peas it does make a difference. We did this this year and the results have been spectacular. They love to get their roots down deep before making their top growth  and the more vigorous the early growth the longer your cutting season.



Soil temperature is very important when it comes to Sweet Peas. By positioning your trellis where  they will enjoy afternoon shade the season for Sweet Peas can be extended well into summer. This has been very effective for our Late-spring sown plants which are still in flower now in March.


We prefer to start our seeds in tubes in one of the glass or shade houses, when doing this we are assured of having a full contingent of young seedlings to plant out. We do not soak the seeds as is traditionally advised but the tubes are kept evenly moist whilst on their heat bed. If you are sowing directly  I think it a good idea to soak the seeds as it probably does speed things up a little.

We sow our seeds in good quality (sifted) potting mix to which has been added a handful of lime, and our own mix of organic fertilizer. We sift our own potting mix as we have found the various seed raising mix just that little bit too fine for our needs. Tamping down the seed-raising mix really well is very important not only for germination but for later on during the transplanting stage - the root ball will hold together better.



When the seedlings are 6 inches high or so we remove the tip  to encourage bushy plants with better root systems.



 Consistent moisture is essential , particularly in the early stages and we have found drip hoses a terrific way of delivering this with the bonus that later on there is no water  damage to the flowers from sprinkler. We place three lines on top of the trench , plant two rows of young seedlings between them  and then just mulch over  with stable manure to  disguise the plastic. This method, used by championship growers in Britain has made a significant difference to our growing success.

Erecting Trellis

Whilst we get around to erecting a beautiful wooden trellis/ pergola with removable netting  we make do with bamboo canes ad netting, this looks a bit tawdry before the vines have got a go on but it does the job. Fine plastic netting means that the little tendrils are not burnt on hot days during summer but in most gardens Sweet peas are long gone before that sort of heat.


We haven't got around to setting up the liquid feeding through the dripper lines yet so in the meantime we still go along with a watering can of Seasol and Fish emulsion when we think of it over the summer. I would like to say it was every fortnight but the truth is it is somewhat less disciplined than that and  any number of times during the growing stages helps immensely. Once the vines are about half way through their flowering we stop the feeding and concentrate on dead-heading  so that buds continue to be produced. If let to set seed flowering drops away surprisingly quickly.

Choosing Varieties

Our experiments with early flowering varieties has yeilded little in the way of earlier flowers, this is due, I think, to the open skies of Australia with plenty of light reaching the plants even in winter. The main choice then is between Grandifloras and Spencers. Grandiflora varieties do have the edge when it comes to perfume but they are not as frilled in shape or as  long in the stem as the Spencers and as both these attributes are important when it comes to Sweet Peas a s a cut flower I think the Spencers win every time.

Choosing colours is very personal and much depends on whether the effect you going for is for the garden or the house. In the garden stronger coluors show up best as the subtle ombre effects of many pastel varieties becomes lost in strong light, but cut them and bring them into the house and everything changes. The delicacy of their shaded petals  immediately becomes more obvious as you arrange them in their vase.

Of the many varieties available our favourites are:


High Scent ( April in Paris) Anniversay                       
Mollie Rilstone Frolic
Leamington Gwendoline
Charlies Angel Kippen Cream
Princess Elizabeth Old Times


 Even though the blue varieties are said to have the strongest perfume  the delicate colours of these varieties blend beautifully together and their perfume will scent a whole room.


Sweet Pea bouquet using  April in Paris , Gwendoline, Frolic and Anniversary

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