“Fierce mild” my neighbour said when commenting about the weather. While this is an Irish-ism that simply means very mild, it struck me as particularly apt, in that this mildness, while very welcome to us humans in the autumn, can have a fierce effect on our native flora and fauna.

The Spindle Tree comes into its own in October

It’s true that up now we have had a wonderful long, mild autumn. Warm sunny days, perfect for long walks looking for wildflowers, have lured us outdoors and convinced us that this will last forever.

From the top: Corn Spurrey, generally finishes blooming in September; Red Campion – by now we expect to see the empty seed pods, but along with them there are a few flower heads still blooming

And the wildflowers are certainly hanging in. I’ve seen lots that would normally be over by now, but who find a sheltered spot and bloom merrily away for our enjoyment. It’s been lovely, and I can’t help wishing it would last well into November. But the truth is that an unusually mild winter is not good for our plants.

Rose hips – seasonally correct; but look at the branches, are they starting to bud?

The factors that cause winters to be milder than usual are many and complex. Forecasters appear to be conflicted as to whether Ireland can look forward to winters in the coming decades that are shorter and milder than average or longer and colder. Both scenarios pose problems for plants and insects and therefore for those of us who depend on the health of our pollinators. And that, actually, is all of us.

Found on the same south-facing slope; Top: Musk Stork’s-bill – it should have finished flowering in July, but it’s found a sunny spot and is still blooming; Bottom: Red Dead-nettle can bloom well into November 

While it’s impossible to extrapolate from recent weather experiences to talk about long-term trends, a mild autumn can show us what can happen when temperatures vary from the norm. We already know that our springs have come sooner than they used to fifty years ago (two to three weeks earlier!) but we have also seen an increase in average temperatures in the autumn, which can lead to prolonged spells of mild and sunny days, such as we are experiencing at the moment.

Ragged Robin is a spring/summer flower and it’s a little worrying to see it blooming this late

Mild temperatures in the autumn can trick flowers into thinking that it’s spring, and time to wake up and grow. Trouble is, there’s bound to be a cold snap sooner or later and the fragile bloom will freeze and it won’t bloom again when true spring arrives.

This Long-headed Poppy and Common Ramping-fumitory are blooming late, especially the Poppy

Our native and naturalised plants have adapted to our ecosystem, including our climate, and any disruption to that has to be, in turn, adapted to. But this takes time – centuries, millennia even – for many organisms: the rate at which our planet is warming may not give them the time they need to make that adaptation.

Sweet Alison, rare in West Cork, on the same sunny slope as the Musk Stork’s-bill and the Red Dead-nettle

That’s all a bit doomsday, and I’m never inclined to embrace the most alarmist predictions, but whether related to global warming or not, a mild autumn can a problem for wildflowers. Flowers that appear in late summer and normally bloom into September and early October are still nodding away in the fields and hedges this year, and that’s lovely to see.

Common Chickweed – this one blooms all year round!

What’s not so great is that I have seen a few spring/early summer flowers too, long after they should be asleep. I can only conclude that they have sensed that it’s time to produce their one and only set of buds and that the first deep frost will probably kill them.

A lovely lilac-coloured variety of Sea Rocket, still in full flower at Barley Cove

A longer growing season also provides opportunities for insects and fungus that would be kept in check by colder weather to predate on plants. Plants that arrive from warmer climates, whether by accident (hitching a ride on a long-distance freight truck, or hidden in nursery stock) or design (imported for garden use) can start to reproduce once our climate catches up to the conditions they have been bred for. A good example of this is the snowy white egret – it only arrived here 20 years ago!

Little Egret; Russian Vine at Rossbrin Cove, an unwelcome invasive species

A fierce mild autumn is lovely, and we are certainly enjoying getting out and about on our favourite walks and our various explorations. But it’s time to cool down now – for our flowers’ and insects’ sake and ultimately for our own.

I love the colour that the bracken turns at this time of year

The good news is that a north wind arrived yesterday and suddenly it’s chilly. Good news for the wildflowers, that is. Not so great for us – we will miss those sunny walks!

Beautiful West Cork in October