blog

Follow our progress running the nursery, watching wild bees, keeping honey bees and creating our own bee-haven in south Oxfordshire

The 'June gap' - a tough time for bees?

borage honeybee.jpg

The 'June gap' is as strange phenomon which appears to occur in the UK and some other countries.  This term refers to a period when there is a sudden reduction in the amount of pollen and nectar around to feed honeybees (and, presumably, other bee types too but much harder to monitor their food intake and brood production quite so closely).  This is an problem for bees because in May, the colonies of many bee species are growing rapidly. Honey bees will be reaching peak colony size and bumblebees will have thier workers out in force. The flowering times of plants follow the following pattern:

  • During spring: in addition to many early flowering herbaceous species flowering there are vast volumes of pollen and nectar produced from trees and hedges.  To put this into perspective a single mature lime of willow tree will yield the same amount of bee food as an acre of wildflower meadow.
  • Then in May, if your bees are rural types, the rapeseed flowers bringing a serious glut.
  • But come June, all of that is over, and the grass is now long suppressing most wild flowers.
  • Then by July a variety of tall herbaceous species find ways to push up through the grass and once again we have flowers through to September. Also at this stage late flowering fruit species such as brambles come into thier own.

But why is there less flower in June? It doesn't make much ecological sense as you would imagine that some species of plants would evolve to take advantage of the reduced competition for pollinators.

I am not totally convinced that the June Gap exists in the UK  - or maybe not every year  - and is really just beekeeping folklore to explain years when honey yeilds are poor.   The weather will affect the times when plants flower and can make the gap greater or smaller. Also, some plants will be in flower - just less.

Here are some of the best garden perennials that do seem to still flower through this period so if you have a chance to plant some the bees will be greatful:

- Most of the hardy geraniums including the native geranium pratense, Veronica spicata, helenium 'Sahins early flowerer', nepeta mussinii, centaurea montana. (see plant for more)

-  Lots of herbs; thymes, coriander, rosemary and, best of all borage (pictured above)

and..... if you have an area for seed Phacelia which will flower for 6 weeks right at the time the bees need it.

 

Echium vulgare: one of our 'top 5' plants for bees

iStock_000013467717Small.jpg

This is a one of our top 5 plants for bees; a native that is so dramatic it looks exotic.

Also known as Vipers Bugloss, Echium Vulgare, this native British biennial is a member of the boraginaceae family and,  along with its cousin, borage, it is a massive source of nectar for bees and a great generator for honey.  From June through to September it produces tall (4ft/120cm) spiky spires of deep blue flowers that attract the full range of bees. It is particularly special for bees because it continues to produce nectar throughout the day and for abut 3 months; so you will even see bees on it in late afternoon when other flowers have dried up.

The vulgare (common) species  is not a plant you will ever see in garden centres and I think this is probably because the leaf rosette looks really ugly before the flowers come.  But from those scruffy leaves suddenly comes a spire of wonder. It grows wild in the chalk downs where it thrives in well drained soil and although it is a biennial but it will  self seed in poor dry ground; I recommend sprinkling some sand or grit under it to improve seed germination if you have nice garden soil.

We sell echium vulgare

Bee plants - the trial plot in June

The idea of the bee-plot is the design a planting scheme that will ensure continuous flow of nectar and pollen throughout the season. So naturally when choosing the plants for this trial plot I was quite determined to make sure that I had a range that would ensure flowering right through the 'june gap'. Up till the first week in June this was going well but now most of the earlier flowering plants have almost finished and the next batch are still to bloom. It think the very warm spring weather had some bearing on this as it accelerated the flowering of the poppies and geranium pratense.  And now it is much cooler than expected. The borage is just beginning to flower but the agastache and monarda are not quite ready.  The only thing really flowering happily is the oxe-eye daisy which may not self seed when everything else gets established.

I think that there will be lots of  flowers by the end of the month so hopefully this is just a two week lull.  All the same, it shows that the trial was necessary and I now know what to adjust in the design.

Plants for bees - perennial geraniums

Geraniums are not often top of the lists of plants for bees but I think they are under-rated. Geraniums are a real stalwart of any herbaceous border. The extensive range starts blooming in April with the Phaeums and keeps going right through to August with the Oxonianums which repeat flower for a very long time.  But, as with all garden plants, they come from the wild and in the UK we have two very common native geraniums:

 

1. Pratense (bloody cransbill) - a tall willowing blue flowered plant that you commonly see with its head above the grass flowers at the edges fo the road and

2. pyrenaicum - a low growing, creeping variety with masses or small purple flowers

Both flower from end of May till end of June and hence provide a regular reliable source of  'June gap' nectar and pollen.

All the geraniums (with the exception of a few cultivated doubles) have an open flower which is perfect for all types of bee.

If they are planted in a big clump then you will see a variety of bees on them. Thier flowers are not packed closely together and so honey bees might find them an inefficient source if its only a single plant if there is competition nearby.  However, if other flowers are scare in June then the reliable geraniums will be most welcome.

 

 

Phacelia - good for lots of different bee species

We are finding that this plant is really good for many different types of bees. Here are results of our brief study: Our phacelia plot is about 24 square meters and we first studied the bee activity  in June at midday in full sun for about 20 minutes.  We then continued observing for more types of bee at various other times of day for 5 minutes at a time.

Bee density: approximately 9 bees per square meter when in full sun, 5 per sqm at when overcast - the difference being reduced numbers of honeybees when its cloudy.

Bee diversity: & species observed, most of them repeatedly:  honey bees were the most common (but our hives are only 50 meters away)but we also saw the following:

 

 

 

 

 

 

 

 

  • buff-tailed bumblebees
  • red-tailed bumblebees
  • early bumblebees
  • brown banded carder bees
  • common carder bees
  • field cuckoo bumblebees
  • tree bumblebees
  • garden bumblebee (just one)
  • hairy footed flower bee (just one)

Quite a haul!

Observed behaviour:

The honey bees were purely collecting pollen but most of the bumblebees were after the nectar.  The latter have to push their faces past the forest of stamens to get into the small centres to the petals.

It was quite common to see multiple bumblebees in a single flowerhead but the honey bees will not go near a flower that has any other bee on it.

The pollen is dark purple/blue and makes the bees legs look like they have a plaster  on.

Growing phacelia

We  cast the seed on the surface in a rough patch of cleared earth in our field. Then we totally ignored it and left it to fight amongst the native weeds and grass.  It has faired well with this treatment and represents just over half of the vegetation in the plot.

Plants for bees - phacelia with blue pollen

This plant is a great one for bees and so easy to grow in really rough ground.

I am generally all about planting perennials for bees so that you have a guaranteed sources of nectar and pollen every year but there are a few annual crops which cannot be ignored for their bee-value.  Phacelia is one of them.  It provides masses of blue pollen for honey bees and nectar for lots of other types of bee (see http://www.rosybee.com/?p=345  for our observations on types of bee).

In several countries (US, Germany) it is grown as a green manure to enrich arable land. In the UK is is sometimes included in the mix for game cover but I have not seen it sold for crop rotations although I have seen it sold as a green manure in small packets in garden centers - presumably aimed at allotment holders. It doesnt seem to have any product other than its humus benefits..........and its masses of pale purple flowers.

My sister gave me a 100g packet she picked up in Germany and we had a patch of field going spare not far from our bees.  So, having rotivated to break it up a bit I liberally chucked the seed around, raked it over roughly and then ignored.  In spite of it being the driest spring on record and having to compete with well established weeds, it has come up thickly and now (first week June) is just beginning to flower.

As part of the plant trials I will be observing how it performs for the following questions:

1,  how attracted the bees are to a clump 3mx8m?

2,  the flowering timing - will it fill the 'June gap'?

3, after flowering will it self seed and continue to compete against the couch grass and thistles?

My observations are that the bees of all types love it and this is a fabulous 'June gap' filler. However, being an annual, you do need to sow it in freshly prepared ground every year.  For a selection of perennial plants that will reliably flower every year and support bees, go to the rosybee plant range.

Bee plants - the trial plot in May

What a change! To look at the bee-plot now you would never know it had only be planted last September.  I did pack the plants in closer than I would normally recommend but it is now almost completely filled out. The succession of flowering is also going well with the Oriental Poppies and the Geranium Pratense picking up from the Doronicum and Erysimum.

The self-seeding section also appears to be working with the Borage beginning to power up through the Mysotis as it is ending its month of flowering.

This May has been a good few weeks ahead of normal so I am anticipating the 'June Gap' might be early too.  In the general area, the rape is over as are the Hawthorn and most of the flowering trees.

The Elder is approaching full bloom right now but after that comes the tricky time for bee nutrition and so I am hoping the bee-plot will pass the test supplying pollen and nectar in the gap.

Look out for Junes update for find out if it does!