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Sowing Wildflower Seeds

Published in Organic Gardening Magazine - February 2006

Slowly, winter is receding behind us and all thoughts are on spring ahead.  It is probably still pretty cold and damp wherever you are but if, like me, you are itching to get started on a new project, February is a great month to look at sowing a range of wildflower seeds to enhance your garden and its wildlife potential.  Furthermore, many wildflower seeds need to experience frosty weather before they will germinate – a process known as vernalisation - and there is no better way of achieving this aim than to allow Mother Nature to do her work.  If, in late autumn, you didn’t get around to sowing your cowslips and primroses for a grassy bank somewhere, or tufted vetch for a hedgerow bottom, you still have time to do this before spring arrives.  As our climate continues to change, February is often the coldest month of the year and a perfect time to get this important job under your belt.

But why has this strategy evolved in some species?  Seed dormancy is an interesting and complex subject and clearly it is of great advantage to a species to have the ability to survive in the soil for great lengths of time.  The oldest seed known to have germinated, after being found in an archaeological dig near the Dead Sea , is a palm seed from a tree long thought to have been extinct.  Carbon dating confirmed that it was 2000 years old, and yet still viable.  None of our native wildflowers can quite live up to that amazing seed, but it is known that the common field poppy can remain dormant for many years, only springing back to life after a period of cold weather and exposure to sunlight after years in the dark.  Seeds truly are amazing structures.  The majority of species that have developed this strategy for survival usually have very tough seeds coats and tend to be species that produce relatively few seeds, although the poppy is just one of the exceptions to this vague rule. 

wildflowers seeds

The vetches, which do require vernalisation, may only have ten seeds in a pod – very few in comparison with the number that may develop in the seed pod of a red campion or greater knapweed.  Making sure that seeds germinate in an environment that is not hostile to tiny seedlings is important to the survival of any plant, so strategies to ensure this have evolved in many species.   By coming to life after several periods of cold icy weather, there is every chance that growth will continue, although the vagaries of the British weather can leave a lot to be desired!  It is always best to sow wildflower seeds, especially those of perennial plants, in seed trays or pots, rather than directly into the ground.  Having them in pots or trays ensures that you can keep a careful eye on them, and with those species that germinate over a period of time, you can prick out the seedlings when they are large enough to handle, thus making more space for the latecomers.  To sow, firm peat-free compost gently into a small seed tray or pot and sprinkle your seeds as evenly as possible on the surface.  Cover with a thin layer of horticultural grit and water carefully.  Now place your seed trays outside where they will catch the full force of any cold, frosty weather.  Keep a watchful eye on them, watering gently if conditions are dry, but don’t expect to see any seedlings until March or April.

Some seeds have spectacularly tough seed coats.  Many species within the vetch or pea family fall into this category, and sainfoin Onobrychis viciifolia, with its stunning pale pink spikes of flowers is a case in point.  The large, rather beautiful seeds have a rough, pitted surface and their edges are spiked.  Two winters may be necessary to break down the seed coats of this species, so scarification (rubbing the seeds with sandpaper) as well as vernalisation, is needed to get them started, unless you are prepared for a long wait.  Other useful wildflowers in the vetch family that provide nectar and pollen for insects and seeds that small mammals enjoy, include the narrow leaved everlasting pea Lathyrus syvestris a rather special and unusual climber with subtle pinky-brown flowers, meadow vetchling Lathyrus pratensis a plant with clinging tendrils and bright yellow flowers, and of course the versatile tufted vetch Vicia cracca suitable for including in a meadow, rambling through a hedge or training up trellis or wigwams.

tufted vetch and meadow cranesbill

The wild geraniums also benefit from being sown this month as they too germinate more reliably when subjected to a good cold spell.  Their germination is variable and if you sow twenty seeds of meadow cranesbill Geranium pratense with luck you will have ten germinating in April, another three in May and then an odd one every now and then.  This can be frustrating to the gardener who is used to everything coming up at the same time, but to the wildflower enthusiast, these ‘extra’ seedlings seem to come as something of a bonus when they are least expected!  Geranium seeds can also be scarified before sowing for a bit of extra help. 

The range of native cranesbills suitable for garden cultivation is brilliant, with plants suitable for every garden location - sun or shade, meadows or rockeries.  The meadow cranesbill is perhaps the best, its pure sky blue flowers enhancing a grassy area for several weeks in the early to mid summer, but hedge cranesbill G. pyreniacum is a favourite of mine, having subtle mauve flowers smaller than those of its meadow cousin.  Primulas are well known for their temperamental nature where germination is concerned.  How many pots of cowslip seeds Primula veris have been confined to the compost heap because they did not germinate after a spring sowing?  If only these were kept until the following spring, there would be cowslips galore for every lawn!  The same is true of course of primroses and other members of the Primula family.  Sow now for hundreds of seedlings in a month or two.

cowslips

There are many species that benefit from this harsh treatment but the last major group amongst the perennials is the bulbs.  The two most commonly grown native bulb species in our gardens are snakeshead fritillary Fritillaria meleagris and bluebell Endymion non-scriptus.   Growing these from seed is fun, but requires great patience.  First a period of vernalisation is required before germination will take place, but then maybe four or five years of growth before flowering size is reached.  A labour of love, but worth it in the long term.  Knowing a little about the germination requirements of the seeds you are planning to grow really does reap rewards, both financially and from the amount of satisfaction you’ll get from producing your own wildflowers using the method that nature intended.  Get sowing now for a garden full of wildflowers this summer.