Bee part of the Ivy League!

Author - Francis Ratnieks Bees Wildlife

The ‘LASI’ team at the University of Sussex has been carrying out pioneering research on honey bees and other insects around Brighton, revealing some fascinating stories to share with local people. Ivy is one of the few plants that blooms in the autumn (from early September to mid-November), although most people don’t even know that ivy has flowers! Have a close look at mature climbing ivy (which has oval leaves) and you will see masses of small yellowy green petals – ok, they’re not obviously attractive! Few appreciate that ivy is the most important source of nectar and pollen for insects at this time of year, a critical period to gather energy before winter sets in. Our studies of autumn pollen loads collected by honey bees shows that 80% come from ivy, and most is nectar rather than pollen. Of course ivy is in no way a rare species, in fact it can be found almost everywhere in both town and countryside, hence its abundance makes it available to a wide range of pollinating insects. bee2 Spend a moment observing flowering ivy in the late autumn sunshine and you will undoubtedly see Honey bees and other insects such as Red admiral butterflies (preparing to over-winter or migrate south), Holly blue butterflies, hover flies (mimics of bees and wasps, but lacking a narrow waist) and wasps (rather scarce this year). Rarer species to look out for include the Hornet hover fly (Britain’s largest) and the Ivy bee, a new species to our shores with beautiful brown and blond stripes that is a bit smaller than a honey bee. Have a look at this slide show to enable you to identify insects on ivy. bee1 Whilst ivy is sometimes unpopular with people, as many think (wrongly) that ivy kills trees, it really is worth its weight in gold for wildlife. It not only provides berries and nest sites for birds, but is also almost singlehandedly keeping autumn insects topped up with nectar and pollen, including our declining honey bee populations that play such a vital role as pollinators of our food crops. So, before you tidy up your garden before the onset of winter, spare or at least delay if you can cutting back all of the ivy, so that wildlife can prosper in your backyard and beyond. Francis Ratnieks Professor of Apiculture & Head of the Laboratory of Apiculture & Social Insects (LASI) University of Sussex October 2014

Comments

  • I have had to replace a fence, and had to cut back the ivy to get at it. Now it has not matured enough this season to flower. I want to keep it cut back, but want density and flowers (wrens used to nest in it, and it always buzzed with bees at this time) but how do I manage it’s height and still get it to mature? Any ideas?

    25 Oct 2014 12:35:54

  • Andrew Jordaan:

    I love bees and nature. I also love trees and watch the ultimate destruction by ivy on a regular basis.
    I whole heartedly disagree that ivy will not kill a tree.

    28 Oct 2014 18:36:44

  • Rich Howorth:

    Thanks for your enquiry, Rob.
    It sounds as if you your ivy is regrowing from a mature root stock, but as yet the plant has not progressed from the climbing juvenile stage to the mature flowering stage.
    If you can, you need to allow it to reach this stage, after which you can cut it back – as late in the year as possible (e.g. December) every 1-2 years. The pruning action will actually then stimulate further dense growth of flowering stems.
    Regards – Rich Howorth, Biosphere Officer

    30 Oct 2014 12:38:04

  • Rich Howorth:

    Thanks for your interest, Andrew.
    The effects of ivy on trees is a subject of much public debate!
    As one of our few native climbers (epiphytes) in Europe, from an ecological perspective ivy generally adds significant wildlife interest from its dense foliage for nesting birds and almost unique late flowering for insects’ nectar and pollen, notably honey bees prior to the winter.
    Ivy is not a parasite on trees, but uses them for support to grow on which adds to their weight load and the ‘sail effect’ in high winds. There are thus some effects on an individual tree’s growth and potentially long-term survival, however these are generally considered to be outweighed by ivy’s additional ecological value.
    Some further views on this topic can be found here.
    Regards – Rich Howorth, Biosphere Officer

    30 Oct 2014 13:01:59

  • Andrew Jordaan:

    Thanks for your reply Rich. Reading one paragraph from your response below:
    “ There are thus some effects on an individual tree’s growth and potentially long-term survival, however these are generally considered to be outweighed by ivy’s additional ecological value.”

    I don’t consider the long term survival or the ultimate destruction of a tree to be to be outweighed by any human’s attitude to whether ivy has ecological value. I find this kind of approach to be dangerous.
    Having said that I did go straight to the comments section that you suggested in your link. The first comment I came to is listed below and well worth taking note of. Kind regards Andrew

    “It depends on the level of growth. I have rarely seen a tree that has a heavy infestation of ivy that hasn’t been affected in some way. I am a botanist at a science education centre. We manage a 60 acre old growth urban forest used for teaching. Over the past 15 years, English ivy has invaded about 2/3 of the forest and the quality of the tract has definitely deteriorated. The heavy weight of the ivy has pulled down weaker trees and suppressed growth or caused thinning in many of the formerly vigorous trees. We have public “ivy pulls” on one Saturday each month. I can’t even begin to guess how many tons of ivy we have removed. We’ve resorted to using herbicides also, something that was previously never done in our forest. We are trying to re-establish some of the native plants that were choked out. I get ill every time I see English ivy being sold at garden centres. There are much better, less invasive ground covers.

    30 Oct 2014 17:28:02

  • Rich Howorth:

    Hi Andrew
    The difference in perspectives essentially comes down to what humans consider to be of value: every individual tree, or the wider ecosystem of plants and animals that they are a part of.
    It should be noted that the comment that you quote relates to North America, where European ivy is undoubtedly causing a problem as an introduced species, rather than in Europe where it is part of our native woodland ecology and should be valued as such, as you will see from the following comments in the link to the discussion forum.
    Regards – Rich Howorth, Biosphere Officer

    03 Nov 2014 16:48:38

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