The Mid-Summer Butterflies in your Garden

Hopefully since March or April there have been butterflies in your garden, flitting between your flowers, feeding on the nectar on offer and providing you with a great deal of interest.  The last few summers have been widely reported as being poor for butterflies and that’s not at all surprising.  Extremely wet weather or cool summers make life difficult for all stages of the butterfly’s life cycle but especially the larval and pupal stages.  Caterpillars do not like wet conditions as they are prone to fungal diseases when vegetation is damp and pupae may fail to hatch in a cool humid environment.  This can mean that numbers of our summer butterflies vary tremendously from year to year.  There is little we can do when numbers are low  except ensure that we have provided plenty of nectar for the adult insects that have made it this far.  But this might be a good time to put a little thought into ensuring that our gardens are good habitats in which butterflies can breed and set up home, rather than just to do a bit of nectar-shopping.  It is all too easy to forget that the beautiful coloured-winged insects we are seeing in our gardens now are just one phase in a complicated life cycle, and in order to help their numbers increase again we need to ensure that all stages of that cycle are accommodated in our gardens, even if that means a few chewed plant leaves!

I’m sure the butterfly life cycle was something we all learnt about at school, possibly involving tending a few ‘cabbage white’ caterpillars to enable us to see at first hand one of the miracles of nature.  I can still remember the astonishment I felt at seeing a pristine white butterfly emerging from a pupa, which had previously been a rather grubby caterpillar!  It’s a transformation we all take for granted but it is none the less a complicated process.  The change between egg and caterpillar, pupa and adult winged insect has many chances to go wrong.  In fact research on these creatures has estimated that only two eggs in a hundred reach that final life stage.  Compared with the success rate of forty per cent survival of blue tits from egg to adult in their first year, butterflies really do have a hard time of it.  Even the ‘cabbage whites’ deserves a break when the odds are so stacked against them.

Mid summer should see a good number of different species in your garden even if numbers of individuals are low.  Most of our spring butterflies species should have bred successfully by now - the early peacocks, small tortoiseshells, brimstones and commas have hopefully completed a single life cycle.  If you are seeing these insects around your flowers this month they will be second brood adults.  These butterflies are noticeably less battered and more brightly coloured than the spring individuals which may have torn and ragged wings – spending a long winter outside has many drawbacks.  The early insects were the lucky few that successfully survived the winter cold by hibernating in sheltered nooks and crannies, deep in ivy against a fence or wall or maybe in your garden shed.  On emergence their first instinct is to find nectar and their second is to breed. A female brimstone will seek out the leaves of the native buckthorn shrub on which to lay her eggs and nothing else will do.  She can detect the scent of these plants from some distance.  Peacocks and small tortoiseshells place their eggs on fresh spring nettle growth, preferably in a light sunny spot and the comma too will choose nettles, although in my garden they always use wych elm as an alternative. 

All these familiar early breeders will have been joined now, hopefully, by many other native species plus their numbers will have been augmented by the migrants that visit us in the summer from the Continent and Africa.  These include the red admiral, painted lady and sometimes the clouded yellow, a wonderful bright yellow butterfly that occasionally arrives in great numbers.  It seems extraordinary that such apparently flimsy insects can travel such great distances but they often travel here via warm southerly winds apparently sometimes moving at quite high altitudes.  On sunny days on the south coast however, it is possible to see red admirals arriving low across the waves – quite an extraordinary sight.  There is growing evidence that rising temperatures are increasing the likelihood of the arrival of yet more species from more southerly climes, plus some of these migrants are managing to successfully spend the winter with us.  Red admirals are now quite frequently seen in the early spring months suggesting that they are sometimes able to survive our winter weather, especially in the south, by hibernating in the same way as the small tortoiseshell and peacock do.

At this time in the summer the only garden butterfly we are unlikely to see is the orange tip.  This species only has one life cycle per year, the adult emerging in April or May.  However there should be plenty of others around feeding on their favourite nectar sources. 

In mid summer there is not much we can do about the natural reasons for t low survival rates of our native butterflies – the vagaries of the British weather take their toll every year - but we can do much to give butterflies a helping hand by providing nectar and more especially, larval food plants.  It is surprisingly easy to accommodate the food plants of many of our native species but I would tend to avoid nettles in the garden.  By and large they are plentiful in the countryside (especially where heavy doses of nitrogen fertilisers are used) in hedgerows and on waste ground even in cities.  In the garden they can take up a great deal of space and need to be in a protected sunny spot for the red admirals, peacocks and small tortoiseshells to deign to use them.  Keep that sunny spot for a relaxing bench!  However, many of the other larval foods can be added to borders, planted under hedges or, if you have a meadow area, will grow (or already exist) in that long grass. 

Most of the smaller common garden species can be catered for easily.  Orange tips and green veined whites will both choose sweet rocket (Hesperis) and honesty if the wild lady’s smock is not available.  These all flower at just the right time to provide nectar for the adult insects, and food for their caterpillars.   Both common and holly blue could be around your garden.  They will be looking for bird’s foot trefoil and the flower buds of ivy respectively (holly is the food plant of the earlier spring brood).  If you see small blue butterflies flitting about at the top of an ivy covered wall this month, they will be holly blues.  Of the other smaller native butterflies, small copper and the large and small skippers are likely to be garden visitors if only occasionally.  The small copper lays her eggs on sheep’s sorrel, an attractive plant which can be added to a meadow area.  This wildflower is doubly useful - try the leaves in a cucumber sandwich for a refreshing lemony tang!  Hairstreaks sometimes pop up in more rural gardens, especially those with elm suckers in the hedgerows round about.  The white letter hairstreak once thrived on the leaves of these wonderful trees, now ravaged by Dutch elm disease, but a much-reduced population of this gorgeous little butterfly can still be found.  The brown argus is increasing and lays her eggs on the leaves of dove’s foot cranesbill, a common lawn flower.

But a meadow is the key to increasing the number of butterfly species that will breed in your garden.  Our wild, fine leaved native grasses are the larval food plants of the meadow brown, ringlet, speckled wood, marbled white, wall brown and gatekeeper, plus the skippers mentioned earlier, all of which will visit and breed in gardens.  The wall is now sadly much in decline and marbled white is more likely to visit a rural garden but the others will appear in most locations if long grass is available for them to breed on.  A fully-fledged meadow is not essential as long as long as the grasses are fine-leaved native species such as the fescues and timothy and are left uncut for the whole of the summer.  Cutting should only take place at the end of September, and the grass left at a height of approximately 5 cms or more.  Plug plants of larval food plants can be added in autumn or spring, plus some good nectar plants including knapweed, scabious and oxeye daisy.

Something as simple as adding honesty to your borders or the base of a hedge, or creating an area of long native grasses with bird’s foot trefoil, sheep’s sorrel, dove’s foot cranesbill, and some nectar plants, could help our butterflies survive another wet summer.


© Text and photographs Jenny Steel 2017