Sowing Wildflowers in Spring

We sell more wildflower seed in Spring than in late Summer, which is odd. To be fair all the books say you can sow in April / May or September / October - or - to be more accurate, when the soil is warm and not dry.

We're beginning to rethink our advice and thinking of suggesting people consider the late summer / autumn window much preferable to spring. In the short term it's not a great commercial message, but in the end I think our customers will thank us for it. 

It used to be that the only disadvantage to sowing in spring - which after all - is not what what nature intended - was that some seed will just sit in the soil. Some wildflower seed needs to be exposed to long periods of cold to germinate. The best known of these is Yellow Rattle, Rhinanthus minor. We are bombarded with requests for seed at this time of year, but it should only be sown from August to December using freshly harvested seed. The seed has limited viability, so any sown now is going to show poor results next March. We make a point of selling all our stock as quickly as possible.

This is frustrating, particularly as many of the direct harvest mixes we sell include a goodly slug of it, and the seed isn't cheap. Sow a meadow mix now which includes it and no (or limited) Rattle will appear next year, so it will need to be oversown in September. An expensive and tedious exercise.

There's another, and increasingly important reason, why I'm beginning to think sowing in late summer or early autumn is a better idea.

I'm not sure what the record books will say, but apart from the recent weather being cold - too cold for wildflower seed to germinate - it has also been incredibly dry in Somerset at least, after a period of extreme rainfall. These are terrible conditions to seed in. I have a number of seeding projects to do locally and the seed is languishing in our store until we see some rain and warmth. Not only is there the issue of germination, but the soil is difficult to work at the moment too.

Dry Marches aren't new - Chaucer knew about them over 600 hundred years ago:

When April with his showers sweet with fruit
The drought of March has pierced unto the root...

What does seem to be changing is that these droughtlike conditions are persisting until late Spring. We've seen nothing of April's showers sweet with fruit in these parts; our soil (below) is cracked, cold and thirsty.

The time to seed could eventually come much later than the text books suggest, as dry springs have been something of a feature of our weather over the last few years. Unless you're sowing cornfield annuals, there's no harm in sowing in June if it's wet - much better than sowing in a hostile April. 

Some areas of the UK are experiencing particularly challenging weather, and not just for wildflowers. We are already saying to buyers of our bare root plants in East Anglia and some of the Southeast that they should get their new hedges and trees in the ground in November and December. Low rainfall after that means higher failure rates for February / March plantings.

Hostile weather also impacts on growing new stock in the nursery and seed yields. Poor growing conditions mean more expensive and smaller plants, and less seed.  

I'm sure these changing conditions are related to climate change. It's making sowing and planting increasingly challenging, and we have to adapt to that if we want to conserve and increase the number and diversity of our native plants in the landscape.