There has been much in
the media recently about the effect a few cool, wet summers have had on UK butterfly
populations. Surveys carried out by the organisation
Butterfly Conservation have revealed that even our most common
species, including the garden favourite the small
tortoiseshell, have declined dramatically in some cases to the
point of causing concern about their long term survival.
Those most at risk are butterflies that already have small
populations in isolated locations such as the high brown
fritillary, species whose requirements are very specific
including the black hairstreak, or butterflies on the very edge
of their natural range, the swallowtail being an example.
Changes in our butterfly populations occur all the time but a
decrease of 45% in the number of small tortoiseshells is cause
for much concern. Other figures from the survey reveal huge
decreases in numbers of migrant species such as painted lady
and clouded yellow.
As wildlife gardeners
we are used to the idea of providing nectar for everyday
insects. Many common nectar feeding insects - especially honey
bees and bumblebees - pollinate our fruit, vegetables and
flowers and it makes sense to welcome them to our gardens for
that reason alone. These beneficial insects along with
hoverflies, ground beetles, ladybirds and lacewings have been
elevated in their status over the last few years and are now
seen by most gardeners as useful creatures to have around,
which they certainly are. Butterflies however are a rather
different story! Die hard allotment holders and less well
informed gardeners will still persecute butterflies (and
of course moths) on the grounds that they eat everything in
sight, their caterpillars nibbling away at leaves of precious
plants - a quite erroneous assumption.
But as numbers
continue to decline, is simply providing nectar enough to help
our native butterfly species? As gardeners who see the
wildlife around us as an important part of the garden
ecosystem as a whole, what can we do to help to reverse the
loss of some of our most beautiful native insects?
The British Trust for
Ornithology and the RSPB regularly release figures which show
that garden bird feeding and the provision of nest boxes has
helped our native birds. Perhaps we can apply a similar logic
to helping our garden butterflies. Growing the usual
butterfly nectar plants is a good start, but encouraging
breeding is the most positive action we can take. So how do
we go about this? Is a nettle strewn garden the logical
conclusion to this idea?
First of all, useful
as nettles are to some species of butterfly, there is a common
misconception amongst the uninitiated that ‘leaving nettles
for the butterflies’ is the only thing that one has
to do in the garden to help these insects. As with so many
aspects of providing for our local flora and fauna, it’s not
as easy as that! Small tortoiseshell, red admiral and peacock
butterflies do all lay their eggs on nettles and the
caterpillars therefore eat the leaves, plus comma and painted
lady will sometimes use them although they have other
preferences – comma prefers hops and painted lady, thistles.
Leaving a clump of scruffy nettles in a shady place – under a
tree or behind the garden shed - will be of little use to
butterflies.
Other insects (including some species of ladybird) will use
nettles in this sort of situation, but butterflies are
creatures of warmth and light and they like their nettles in
warm, light situations! Nothing but the sunniest, warmest spot
in your garden will do and fresh young nettle leaves are
preferred. Living in a rural location I don’t intentionally
leave any nettles for breeding butterflies in my garden as
there are masses in the fields all around me. But inevitably they
find their way into the garden and I keep an eye on them for
butterfly activity, but most of those that grow in the shady
parts are composted.
However, our nettles,
whether you want to grow them deliberately or not, cater for
only five of the twenty or so species that you could attract
to your garden. The larval food plants of these species are
a lot more attractive and easier to handle than the stinging
nettle, so set your sights on helping some of the most
beautiful of our native insects – the stunning orange tip,
elegant ringlet, dazzling common blue, and wonderful butter-yellow brimstone.
The orange tip is one
of the ‘white’ butterflies and has declined considerably (26
%) in recent years. This was a butterfly of wet meadows,
laying its eggs on the spring flowering lady’s smock,
sometimes known as cuckoo flower. This delicate plant with
its pale mauve flowers was once a common sight in country
meadows along with cowslips and in some locations the snake’s head
fritillary. Its other larval food choice is hedge mustard,
also called jack-by-the-hedge. This useful wildflower is edible,
imparting a lovely hot garlic taste to salads, or it can be
cooked. This is easy to grow at the base of a hedge, or
lady’s smock will thrive in a damp patch next to a pond. A
further, very attractive alternative is honesty which the
orange tip will use in the absence of the other species. Useful in any wildlife garden, honesty’s violet
flowers, which also provide nectar for the adult butterflies,
are followed by the familiar ‘moon penny’ seed pods containing
seeds so large and nutritious they will keep greenfinches
entertained for ages.
Brimstone, the yellow
winged harbinger of spring, is another easy butterfly to
encourage to breed. This insect is more particular than some
others in terms of laying its eggs and only the two species of
buckthorn, purging and alder, will suffice. These are easy
little shrubs to grow: alder buckthorn prefers damp acid soils
and purging is happier on drier lime rich substrates. The
female (cream coloured) brimstone can detect the scent of this
plant from some distance. Buckthorn can be tucked into a
hedge or grown amongst other shrubs. If there are brimstones
in your area, they will find it.
The blue butterflies
are a group of tiny, bright winged insects that in general
live in quite specialised habitats, but the common blue is
relatively easy to encourage to gardens if its larval food
plants are available. First choice is bird’s foot trefoil,
which is easy to grow at the front of a border, in a scree
garden, on a living roof or in short grass. Bear in mind
though that if you plant it in grass you will not be able to
cut it for a couple of months in the summer. If this sounds a
bit too problematic and you have a pond, try growing greater
bird’s foot trefoil – a plant of boggy meadows and waterside
habitats. The common blue will use it just as readily and
it’s a lovely plant to enhance a wildlife pond.
Lastly - the elegant
ringlet. Strangely this butterfly actually increased in
number in my garden last summer, possibly due to the weather
and the timing of its breeding
season. This lovely butterfly, together with meadow brown,
gatekeeper, large and small skipper and several other species
all deposit their eggs on native grasses and their
caterpillars feed on the grass leaves. Only meadow
grasses will do
for them, so leave some long grass in a sunny corner and see
what happens.
Helping butterflies to
breed, just as we have aided garden birds such as blue tit and
great tit, house sparrow and robin with carefully designed
nest boxes, could well make a difference to butterfly numbers
in the future. Many common birds now rely on our gardens for
food and shelter. Maybe as conscientious wildlife gardeners,
we can do the same for some of our most beautiful
butterflies. If you plant both nectar plants and larval food
plants you could expect twenty or more species of butterfly to
visit your garden instead of just a handful.
Growing Nettles
Nettles need to be in a sunny and sheltered spot for
butterflies to use them. Make sure there are young fresh
leaves by cutting them back in April and don’t get your hopes
up! Nettles in gardens are not often used by butterflies
although other insects will use them. Butterflies seem to
prefer larger patches in the countryside.
Plants for breeding
butterflies Try growing lady’s smock, garlic
mustard, bird’s foot trefoil, native fine-leaved grasses such
as the fescues, wild sorrel (for small copper), honesty and
buckthorn.
Make
a small meadow
Leaving an area of
grass in your garden uncut could encourage the butterflies
that use native grasses as a food plant. Even better, take up
an area of turf and sow a native grass mix. Even without any
wildflowers this will still make a good habitat for wildlife
and may attract meadow brown, gatekeeper and speckled wood
which are the brown butterflies that most commonly visit
gardens.
Don’t forget nectar
flowers Buddleia, Echinacea, catmint, sedum,
Michaelmas daisy, scabious – there are butterfly nectar plants
for every garden. Do a bit of research to find out what’s
best for your soil.
Why
butterflies don’t do well in wet weather
There
are several reason why butterflies don’t thrive in poor
summers. Firstly they can’t fly in pouring rain which means
there are fewer chances of mating and laying eggs, and equally
important is that both eggs and caterpillars are prone to
fungal diseases in damp conditions, meaning that the next
generation is much reduced in numbers. |
