Pollination at Yarra Valley Cherries

September is always a challenging time on the orchard, to decide when to bring the bees in for pollination. This year, we judged the buds were coming into blossom in the first week, so we gave Tom our bee supplier a call.

He arrived at 5am on Tuesday 7th September and unloaded 60 beehives which he placed at various locations throughout our orchard. With our 20,000 cherry trees, that’s about the right number of hives to optimise successful pollination.

Tom had just driven his bees down from Shepparton (moved through the night) where they had been pollinating canola for the previous couple of weeks. Before that, they spent a month up on the Murray working the pollen on the almond blossoms.

Canola is a very rich food source for bees. It’s full of protein and thus has good nectar. The food availability is so abundant in the canola that by the time they come down to our orchard in the Yarra Valley they are jumping out of their bodies!

When bees have consistent nourishing food sources, they breed, and the eggs that the queen lays take 21 days to hatch. She can lay up to 3,000 eggs a day!

That pretty much means that the young bees are being hatched whilst they are on our orchard here in Seville.

Hives

Every hive is home to between 30,000 and 50,000 bees. With an influx of the new baby bees hatching, some of the hives can become over crowded, which then causes part of the colony of bees to swarm out, and find another place to live. This can often be on big gum trees on the property.

That’s when we need to give Tom a call to tell him that he better bring over some new hives so that he can collect the swarming bees and secrete them back into a new home.

Tom’s bees have a mixed breed heritage. Their roots are from Italian honey bee stock, but their genetics extend across other European honey bee varieties, which he believes are the best hybrid vigour for our climate.

After a few days pursuing food from our cherry blossoms, the bees start to recognise that the food supply in cherry blossoms doesn’t replicate that of canola. Cherry blossoms look beautiful, but they aren’t rich in food, and don’t have a lot of nectar, so the bees aren’t making any surplus honey whilst they are here on the orchard. They just make enough to feed the hive and the new brood of bees which are acquiring sustenance.

Even though they are not banqueting, they are doing a great job in pollinating our trees. They move from flower to flower, collecting pollen from the stamen, and picking up the nectar in the cup of the flower. They collect the pollen and store it on the back of their legs with their saliva, and then transport it back to their hive.

It’s this logistics success in transferring the pollen from one flower to another in their quest for food that pollinates each of the flowers that creates our cherries.

Working Hours

Bees are pretty selective about when they work. If it’s below 12°C, they won’t stay out of the hive for long. Between 12-16°C, they start to move out further from the hive, and above 16°C they are really adventurous, travelling up to 2kms away from the hive.

They are not early starters either. They commence working outside the hive around 10am and are back in the hive by 4pm. However, that doesn’t mean that they are having a rest for the balance of the day. They actually only sleep for around 2 hours each day. The rest of the time they are cleaning up the hive, looking after the young bees, feeding, and undertaking general housekeeping within the hive.

When the temperature reaches the high 30’s, the bees won’t work outside the hive. Their role is to keep the hive cool, which requires them to go and collect water for the hive, and then marshal themselves into platoons both in and outside the hive entry.

They then flap their wings in unison to create a cool breeze that goes into the hive, pass across the water that they have brought in, and pushes the hot air through the other hive exit.  It’s nature’s way of evaporative cooling!

During these high temperature days, bees can transport up to 5 litres of water a day into the hive.

The bees head off next week, and are moved to a richer food source than cherry blossoms. They will likely spend the next few months enjoying the flowering gums, eucalypts and wattles which are native to our area. They can leave however, knowing that they have done good work to provide us and you with our cherry crop for this summer.

Regrettably, many of them won’t be around for us to thank – in the summertime these bees will only live for 2-3 months before they are exhausted from all the flying (buzzing around).  That’s why they need to go back to a richer diet to rebuild their strength and vigour, to assist in the production of the next batch of baby bees.

When you taste our amazing cherries this year, spare a thought for Tom and his bees which have done such a great job. We couldn’t do it without you Tom!