Brimstone & Buckthorn
A couple of months ago I spotted a brimstone butterfly (gonepteryx rhamni). With its light yellow open wings, it is rumoured to be the origin of the word butterfly ‘butter coloured fly’. The one that visited us is likely to be the female being pale green.
On reading about it I found out that its larvae (caterpillars) eat only common buckthorn (Rhamnus cathartica) and alder buckthorn (Frangula alnus) so where are they? Of course the butterfly could have just been passing through. I’ve not seen these plants locally but would love to know if anyone knows of any in the area?
Both of these plants look pretty similar to dogwood (Cornus alba). Common buckthorn are not a particularly showy shrub / small tree that has black berries on about now. Alder buckthorn grow slightly larger to about 6m and have smaller berries that start off white / green, then red and mature to dark purple / black.
The adult brimstone butterfly is attracted to purple nectar food sources and after building up its resources on plants such as thistle, selfheal, knapweed, scabious and wild marjoram will prepare for winter hibernation amongst thickets of ivy and bramble, so I’ll be mindful of this when gardening over winter.
Ivy’s a good one to mention actually, it has two distinct phases of growth. Its first phase is known as juvenile and this is when the characteristic lobed leaves and climbing habit occur. Left a little longer, however, and the plant matures into its adult form that takes on a shruby nature, is non-climbing and has oval leaves. Only when adult does ivy flower and fruit. The small yellow / green flowers are pretty insignificant looking and appear in dome shaped clusters, but don’t underestimate the value of these as a great late food source for pollinating insects from September to November with bees, hoverflies, wasps and late flying butterflies buzzing and fluttering all over it.
In November as it transitions from flower to berry and on into December and January it supplies valuable fat rich food for birds such as thrushes and blackbirds, the more mature the ivy the more flowers and berries it will supply! Not to mention the habitat that it provides for bats, overwintering insects, birds and small mammals.
We have two native ivy’s, common ivy (Hedera helix) which is widespread across the UK and Atlantic ivy (Hedera hibernica) that is found more on the west coast of Britain and in Ireland. They’re pretty hard to tell apart especially as there is a lot of hybridisation between ivy’s but common ivy generally has 3 to 5 lobed leaves and Atlantic ivy 5 to 7.
So if you have a nice mature flowering and fruiting ivy that needs a trim, it might be a good idea for this butterfly and other wildlife to wait until spring and watch out for a brimstone in February / March as they are often one of the earliest to take flight after hibernation.
Photo by David Duarte Crespo
