Blanket bog plants
The fascinating plants of Iveragh.
When I walked onto a living, growing blanket bog for the first time, it looked dry and crisp in the August heat. Making my way in from the margin, my boots became wetter, and I noticed the undulating character of the bog up-close. It’s full of pools, cushion-like mosses, and hillocks with all sorts of sprigs, fronds and flowers on display. I knelt by a pool to admire the ruby colour of a Great sundew growing from a clump of Sphagnum moss - bleached white in the sun. I hadn’t seen this carnivorous plant on Iveragh before. But while my attention was turned, my feet sank slowly, imperceptibly, deeper and deeper into the bog. Feeling my weight suddenly, I pushed a hand into the ground to regain stability, and it too disappeared through the vegetal crust, my knuckles feeling the wet blackness below. Jumping to my feet, the bog around me startled and shivered as though also surprised – sending out waves across the blanket bog. I rested for a moment on a drier patch. A bee whizzed passed on its high-speed coiling flight, shaving just above the sweet-scented bog myrtle leaves beside me.
At a glance, bogs can appear dull, beige and barren. However, a closer look at the plants living on them will reveal that they are anything but that. This article will look at some of the plants that live on Iveragh’s blanket bogs and the fascinating adaptations that allow them to survive in this complex environment.
Blanket bogs, as the name suggests, are blankets of bog of varying thickness (over seven meters in places) that cover the landscape. They formed over thousands of years from the accumulation of dead plant material that that could not decay fully in the waterlogged conditions. Blanket bogs can be seen almost everywhere on the Iveragh peninsula but globally they are a rare habitat. To learn more about how the blanket bogs of Iveragh formed, their importance, and where to find them, see this page.
The challenges faced by plants on the bog
The plants which colonised the boggy ground thousands of years ago came from a range of habitats. They came from mountains, heaths, lake margins, fens, and marshes, all making new homes on the blanket bogs of western Ireland. Arguably the decline of these ‘mother’ habitats in Ireland today means that blanket bogs act as refuges for these species - many of which are endangered.
Most ordinary plants can’t grow on blanket bogs. These habitats are low in nutrients, like nitrogen and phosphorus, which aren’t readily released from organic matter in the waterlogged and acidic environment. The plants that grow on blanket bogs have fascinating ways of surviving and thriving in these conditions. In addition to their natural beauty, it is these highly varied adaptations that the plants have evolved to get around these challenges that make them stand out against the crowd.
Blanket bog plants
Sphagnum mosses are synonymous with the peatlands of Ireland. They are small, cushion forming plants that grow low to the ground. There are 24 native species of this moss group, ranging in colour from greens to reds and browns. They occur mostly in the damp depressions of the blanket bogs where they manage to live on the tiny amount of nutrients contained in rainwater.
While Sphagnums do not play as pivotal a role in blanket bog growth as they do in raised bogs, they are still abundant and influence the bog in interesting ways, for example, they make the bog more acidic by exchanging ions with the surrounding bog water in their search for calcium and potassium.
The Sphagnums are famous for their ability to absorb as much as 20 times their dry weight in water. Because of this and their mildly antiseptic nature, the moss was used as a surgical dressing during World War One. The ‘Society of United Irishwomen’ had depots for collecting and processing Sphagnum moss in Valentia, Kells, Waterville, Caherdaniel and Sneem.
Where the essential nutrients of life are in low supply, plants often form strong relationships with micro-organisms.
Western gorse (Aiteanngaelach) or furze as it is known in Kerry, is an example of this. It is a short, spikey plant with needle-like leaves and is famous for its profusion of yellow flowers in late summer and autumn. It forms an association with bacteria in its roots to capture nitrogen from the air and make it available to the plant. The high nitrogen content (a building block of protein) of the plant is one reason why it was processed into an animal feed in the past. Western gorse was also used to dye wool yellow.
Bog myrtle (Raideog) is another plant that gets nitrogen from a close relationship with bacteria in the soil. This access to nutrients allows it to grow abundantly in very wet sections of Iveragh’s blanket bogs. The most notable and exciting thing about finding this plant is its smell. At all times of year, a crushed leaf or bud will reveal the familiar, yet uniquely floral scent of the plant. This plant is used to make a natural insect repellent as well as adding a pleasant smell to soaps. Its flowers appear early in spring and are a brilliant crimson and bronze colour that glisten against the low sun.
There are three main species of heather that will be found on your journey around the Iveragh peninsula. These are Heather/Ling (Fraoch mór), Bell heather (Fraoch cloigíneach), and Cross-leaved heath (Fraoch Naoscaí). These can be distinguished by their leaves and flowers. The leaves of Ling heather are scale-like and sit tightly against its branches, Bell heather leaves are more needle-like and sit in whorls of three around the stem, while Cross-leaved heath leaves are again needle-like but this time occur in groups of four - a cross shape - as the name suggests. These plants get even easier to tell apart when the flowers appear in the second half of the summer and into autumn. Heather flowers have four separate pink petals while both Bell heather and Cross-leaved heath have pink bell-shaped flowers of 5-6 and 7-9 millimetres long, respectively.
Bees, bumblebees, and honeybees all visit heather flowers to feed on the precious nectar and pollen that they provide. The life of thrips like Ceratothrips ericae are very closely associated with this plant, with the wingless male thrips spending their entire lives inside a single heather flower.
Heathers bolster their nutrient supply by trading essential nutrients with fungi in the soil. These fungi can release nutrients locked up in the peat that the plant cannot access. This inter-species transaction occurs within the roots of the heather plant, where a coiled-up mass of fungal mycelium (the fungi root equivalent) exchanges its acquired nutrients for carbon from the plant.
Purple-moor grass (Fionáin) is everywhere on the Iveragh peninsula. It is a grass that can reach heights of up to 1.2 meters and can form obvious tussocks, especially where heavy sheep grazing occurs. It prefers drier sections of the bog where it is very competitive with other plants. Purple-moor grass gets its name from the purple colour of its tall flowers that appear in late summer. In Kerry it is known as Fionáin, meaning fair or blonde, referring to the colour it turns the landscape over the winter. The reason it turns blonde over the winter is an adaptation that it has for conserving nutrients. It pulls nutrients out of the green leaves and into swollen “bulbs” at the base of the stem for storage between growing seasons.
Lousewort (Lus an ghiolla) is a fascinating little plant that begins flowering in spring. At around 10 cm tall, you would easily miss it (or step on it!) if it didn’t have pink flowers to grab your attention. It comes from a family of plants that are semi-parasitic, i.e. they steal some of their required nutrients from other plants. They do this via their roots which latch onto those of neighbouring grasses and rushes. This is how these plants have evolved to survive in the low nutrient conditions. Other members of this family such as yellow rattle and eyebright can be found in meadows around Iveragh - where their parasitic activity plays an important role in supressing grasses and increasing overall biodiversity.
Heath milkwort (Na deirfiúiríní, meaning sisters) is another nice flower to be able to recognise due to its frequency on the bog and its flowering period that stretches from spring until autumn. Heath milkwort is a low growing plant with narrow sword shaped leaves and purple to blue flowers.
A constant companion on walks around the Iveragh from spring to autumn is Tormentil (Néalfartach). Its ankle height yellow flowers have four petals which are somewhat heart shaped. The plant is very high in tannins, especially the roots, which were used in the past for tanning leather. Tormentil was also used as a treatment for colic after boiling it in milk. I don’t know what the dosage for this is and so do not recommend it.
Purple moor-grass, Lousewort, Heath milkwort and Tormentil are all absent from the raised bogs of the midlands but are commonplace on the blanket bogs of the Iveragh peninsula.
I think of Bog asphodel (Sciollam na móna) as the lighthouse of the bog. Their bright yellow flowers can be seen from afar and let you know where you are. The flowers appear on the bogs of Iveragh in late summer and turn amber as autumn sets in and they release their seeds. The flowering stalks turn brown in winter as energy is passed underground to its fibrous roots. It prefers the drier sections of blanket bog. There is some folklore suggesting that grazing on bog asphodel depletes the calcium in animals leading to weaker bones. The Latin name for this plant is Narthecium ossifragum and means ‘bone-break’ - however this association may also come from the calcium poor environment as a whole that the plant is found in.
There are two types of Bog cotton (Ceannbhán) on the Iveragh peninsula. The quickest way to tell these sedges apart is by the number of seed heads on the plant. If it has a single tuft of white downy fluff (seeds) then it is most likely hare’s tail bog cotton; if it has many tufts, it is most likely common bog cotton. Yellow flowers in spring precede the conspicuous white tufts that appear in May and June.
These two species operate in quite different areas of the blanket bog where they both contribute greatly to peat growth. Common bog cotton prefers wetter bog, while hare’s tail bog cotton much prefers the drier areas of the bog where it forms tufts that are thought to be able to live for up to a hundred years. Common bog cotton will penetrate the bog as deep as a meter in search of nutrients, with its hollow stem pulling oxygen down into the anoxic depths of the bog. I recall on one occasion searching for the base of a bog cotton stem, pushing my arm down into the peat - following the stem carefully - amazed that I couldn’t find where it ended.
Bogbean (Báchrán) is an aquatic plant with stunning flowers that bloom from May until July and easily rivals the Kerry lily in its beauty. It can be found in shallow bog pools but can also be found growing around lakes and other slow moving water bodies. A kayaking trip in Lough Currane would allow sight and smell of these flowers. Interestingly, bogbean seeds float, and so can travel by water before growing into a new plant somewhere else.
The bog orchid (Magairlín na móna) is found growing in damp sections of the bog, among sphagnum moss species. At only 12 cm tall and being green in colour, they could easily be missed if you weren’t looking out for them. They are pollinated by midges - yes, those small pestering insects have a use after all! With only a handful of these plants found on Iveragh in recent years, it is certainly rare. It is also endangered and legally protected, so if you find one make sure to record your sighting with the National Biodiversity Data Centre.
Of all of the above ways that the plants of Iveragh’s blanket bogs have evolved to survive in low nutrient environments, none captures the imagination quite like those that trap and eat insects (insectivores). Iveragh has two common and striking examples of insectivorous plants that you will come across on your travels.
The first insectivorous plant is Large-flowered butterwort (Leith uisce) which flowers spectacularly in late spring and captures small insects using its sticky pale green leaves - that form a rosette close to the ground. The stunning purple flower is over 3 cm long and seems almost out of place - a gem - against the black, wet peat from which it grows. The leaves contain as many as 10,000 sticky enzymatic glands per square centimetre which trap and digest insects to obtain essential nutrients, the curled leaf margins rolling over to secure its prey.
Dr Reginald W. Scully, who wrote ‘The Flora of Kerry’ in 1916 had a very high view of this plant, saying that “no one … who has seen its groups of deep violet flowers … will deny its claim to be considered the most beautiful of the Irish flora”.
The Large-flowered butterwort has an unusual distribution. It is found on Iveragh and other parts of southwest Ireland but is absent from the UK. The next place you will find it growing is in Portugal and Spain!
A squelchy stroll across a blanket bog in May will reveal the tiny Round leaved sundews (Drúchtín móna) stretching out their leaves after the cool winter. These plants can be found from spring until autumn. The leaves have crimson tendrils, glazed with a sticky secretion used to catch insect prey. Once captured, the whole leaf tightens like a fist around the insect and the digestion begins. This process can take hours and when there is only a husk remaining, the leaf unfolds, the insect blows away, and new sticky secretions are released. Somewhat unsurprisingly, the flowers of this insectivorous plant are mostly self-pollinated. I suppose you can’t trap and devour insects regularly and expect efficient insect pollination!
Purple spoonwort liverwort
One fascinating find on the bog is the Purple spoonwort liverwort, or Pleurozia purpurea as it is known in Latin. This small plant appears in damper sections of the blanket bog and looks like an alien worm colony when shining, plump and fully hydrated.
Royal fern (Raithneach ríúil) is the tallest fern native to Ireland. It is a stunning and luxurious spectacle that can be found on the lowland blanket bogs of the Iveragh peninsula. A real meaty fern with thick fronds, it forms a striking pose in the wetter parts of the bog - being very common on the Knockeenawaddra and Pound loop walk near Portmagee (www.ecomuseumlive.eu/iveraghwalks). In autumn it produces a central brown spike of powdery, rusty coloured spores that blow to new parts of the bog to form ferns anew.
Believe it or not, trees are also associated with blanket bogs. Birch and willow trees can be found growing along the margins of bogs, along stream gullies or on the drier hummocky sections within the bog.
Downy birch (beith chlúmhach) is far more common than the other native, silver birch (beith gheal) and can be distinguished by the presence of hairs on its leaves and twigs. Birch is so common on the Iveragh peninsula that many place names such as Glenbeigh, Rossbeigh and the River Behy are derived from the Irish ‘Beithe’ for birch. Birch supports hundreds of insect species and forms close associations with fungal species including Amanita muscaria, the mushrooms that can be found growing around the base of birch trees in Autumn.
Willow trees also love the damp margins of blanket bogs. You’ll commonly find a gnarled eared willow (crann sníofa) or a creeping willow (saileach reatha) lying prostrate over the undulating peat. Both producing yellow catkins in spring - a very important food source for insects early in the year.
In the past, Scot’s pine colonised open bog during periods of drier weather, however, native pine woodlands are rare in Ireland today.
This article has described the broad diversity of plants that can be found living on Iveragh’s blanket bogs. These plants may however be found in other habitats too! For example, you might find individuals growing beside a lake, up a mountain, or on a farm, but they are all found in profusion on our humble bogs.
Blanket bogs cloak vast swathes of the Iveragh peninsula, from coastal slopes and valleys to rocky mountain plateaus. The colours on display in the bog change across the year and there is always something new to spot. In this article, we’ve seen the myriad ways that blanket bog plants cope with the harsh challenges they face growing on the bog - be it catching insects for essential nutrients, using hollow stems to transport air down into the depths of the peat, or parasitising a neighbouring plant for resources. This diversity of adaptation and form make them such a fascinating group to go out and explore.
Listen in to a recording of an online lunchtime talk by LIVE Project Knowledge Gatherer Calum Sweeney, which took place on 12th May 2022. Join Calum on an illustrated journey through some of Iveragh’s most fascinating plants.
Learn about Iveragh's unique blanket bogs, how they shape the Irish landscape and culture and are vitally important for biodiversity here: What is a blanket bog?
Devoy, R., Cummins, V., Brunt, B., Bartlett, D., Kandrot, K. (2021) The Coastal Atlas of Ireland. Cork University Press, Cork.
Feehan, J., O’Donovan, G. (1996) The Bogs of Ireland. University College Dublin, The Environmental Institute.
‘Bellamy’s Ireland: The Wild Boglands’ by Dr David Bellamy.
‘The Wildflowers of Ireland’ by Zoë Devlin, book and website
Irish Peatlands Conservation Council website
Wildflowers of Ireland website
Article and photos by LIVE Project Knowledge Gatherer, Calum Sweeney, except
*Bog bean photos by Anna Kellagher.