Cool Season, Hardy Flowers to Sow in April
In our southern position, there are MANY flowers, for cutting and general garden enjoyment, that perform better sown in autumn. Hardy annuals either require cold stratification or simply germinate at cooler temperatures. Often the plants require a period of cold temperatures, to flower prolifically. And they also cope better with, if not enjoy, cooler temperatures.
Both daylight and temperature are triggers for many plants and seeds. As growers, we can take advantage of the coolness of autumn and winter to germinate and grow hardy annuals.
One indicator of whether you can autumn sow hardy annuals is how reliably they self seed in your garden; if you have cerinthe, poppies, sweet peas, larkspur, calendula and/or cornflowers popping up, you should try Autumn seeding. And if the long range forecast is for a warmer than usual spring, sowing in Autumn ensures a winter transplant date and a long harvest period for these cool loving flowers.
If your winter season is especially wet or your location has a winter weed issue, it is also possible to sow most hardy annuals from mid June - mid August. We cold stratify the seed first and also ensure to sow early enough that the plant experiences the vernalisation period necessary to flower.
LARKSPUR
Larkspur are one of our favorite late spring/early summer spires. They are fantastic cut flowers with a long stem length and a two week vase life. We love them arranged by themselves or in combination with pale foliage and lime green flowers, roses, peonies, bells of Ireland, poppies, celosia, zinnias. With an array of colours, they are quintessential cottage garden flowers occupying herbaceous borders for centuries and much sought after by floral designers.
We have written about how to sow and grow larkspur including direct sowing and transplanting instructions READ MORE →
POPPIES
Breadseed poppies and shirley poppies are both easy to grow hardy annuals.
We have written about both including direct sow and transplanting instructions READ MORE →.
SWEET PEAS
The elegance and fragrance of sweet peas in the spring - summer garden captivates and enchants many gardeners, florist and bouquet customers. Prized for their delicate blooms and intoxicating fragrance, they are easy to grow and mix well in the herbaceous border and into cut flower production.
We share timing, sowing and transplanting methods and much more… READ MORE →.
CERINTHE OR HONEYWORT
With its truly unusual colour, containing silver, green, purple and blue all on one stem, and lovely nodding heads with little bell flowers, this easy to start annual mixes well with other flowers. Cerinthe is cold and frost hardy and will readily self seed.
NIGELLA
Delicate foliage becomes densely covered in buds that open revealing white, multilayered petals surrounding sea anemone like stamen and an interesting seed pod. The flowers have with a great vase life and add a whimsy to bouquets. See More…
CALENDULA
We cannot help but smile on the gloomiest of winter days when we see the bright faces of calendula. It shines in winter and will readily self seed providing endless cheery blooms which are edible! Calendula are also great cut flowers.
CORNFLOWERS
One of the first annuals to bloom in the spring, withstanding cold temperatures and producing abundantly for weeks from a single sowing , cornflowers are easy to grow! A wonderful cut flower, attractive to beneficial insects and edible, it is a dependable, cool hardy annual!
VIOLAS AND PANSIES
We adore the gorgeous faces of violas and pansies in winter. With their nodding heads and blazes of colour, sown now you will have blooms in late winter! Another edible flower that adds colour and flavour to an assortment of winter salads, desserts even cocktails!
We have made a simple one page sheet of what to sow and transplant in April which you can view or print!
There are many more hardy annuals including (but not limited to) ammi, snap dragons, borage, bupleurum, clary sage, fever few…
AND, if you live in a frost free area, you can also sow strawflowers and didiscus now. They are considered half-hardy annuals as they are really only hardy into the few temperatures just above freezing. In climates with frosts in late autumn - early spring, sow these indoors 6-8 weeks before the last frost date and transplant after the danger of frost has passed.
We highly suggest Cool Flowers: How to Grow and Enjoy Long-Blooming Hardy Annual Flowers Using Cool Weather Techniques by Lisa Ziegler