It’s blossom time in California. The hills and valleys are turning white and pink in the almond growing regions as 750,000 acres of almond trees burst into bloom at the same time. These beautiful blossoms have just a few short weeks ahead of them when they need to be visited by a bee. Without bees there would be no almond crop. But in a natural environment bees would exist in the area all year round and once the pollen on the trees had gone they would move on to other blossoms and flowers. Where all the land is given over to almond trees and nothing else, they would have nothing to feed on for the rest of the year and would not be able to survive. For this reason bees have to be imported in to do the job. The number of hives required has increased every year, as more and more acres of almond trees are planted. This year 1.6 million hives are converging on California from all over the US. These bee keepers can also travel to other regions to hire out their hives for crops such as apples, but there is nothing on the whole planet to compare with the size of the almond operation.

The blossoms are delicate – they are out too early in the year to have any leaf protection. It gives the trees more time to produce the nuts but the evolutionary downside is that the weather can damage the blossom. Also delicate however are the bees themselves. Cold or wet weather will inhibit bees from doing their work. Any temperature less than 17 degrees celsius keeps bees inside their hives, and so does rain. This ‘bee activity’ is closely monitored by the growers as the bees need perfect conditions to pollinate all the blossom. Anything less than perfect will reduce the almond crop.

At the height of the blossom period when all the trees are fully in bloom, there will be a window of about 48 hours where maximum pollination can take place. The weather may be glorious and sunny at midday for instance, but if there was a cold start to the day and the bees did not begin emerging from their hives until 10am, then what appears to be a great day for a picnic to the rest of us, may actually have represented a loss of one or two crucial pollinating hours to the grower. This is why they watch the weather and the bees so closely at this time of year. A lot is at stake. The crop last year was worth nearly $3bn dollars to the growers. In recent years the biggest threat to this critical time has been the collapse of many bee colonies.

There was a point a few years ago when 25% of hives were lost and the threat of collapsed colony disorder (CCD) began to look devastating. The danger of CCD has not passed, and the mystery has not been solved. But it is well known that when a new class of pesticides was introduced (neonicotinoids) the problems began, and in areas where these have now been restricted, the bees have recovered.  Meanwhile, for the growers of almonds in California the next few weeks will be crucial.