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16 October 2017 I admit to being slightly surprised on my walks over the weekend by how much autumn colour there was despite the mild weather we have been having. I suppose there were a couple of cold nights at the start of the month, which may be what has triggered the latest wave.

Most of the tinting is happening on trees and shrubs that are normally early to turn. Notably you can see quite a lot of yellow on lime and hawthorn. Some hawthorns in fact have not much foliage left, and the same is true of blackthorn and crack willow.

We are also finally seeing some colour on wild cherry, though not perhaps as much as one would like. Common as a street tree and also fairly frequent in the countryside, cherry can produce gorgeous gold and pink tints - it is one of our most colourful autumn trees. It doesn't always do so, however, and can lose all its leaves without producing particularly bright colours. For the most part it seems to be doing that this year, but some in my locality are starting to perk up a bit.

One of the joys of autumn is you notice individual species in this way - species which pass unnoticed for the rest of the year. Another example is field maple, our only native maple and differentiated from all the others by its small leaves. It is a very good value tree in autumn producing bright yellows (and very occasionally golds) and sometimes tinting in patches in a most attractive fashion (photo). Though it can make full grown trees, it is often seen as a hedgerow or understorey plant and in autumn seems to be everywhere: much more common than it appears to be the rest of the year.

All of these I might expect to be tinting fairly early on, but there are some signs of bigger things to come. There are some golden leaves on beech and oak, both trees that don't fully turn till towards the end of leaf fall, though no sign yet of any big mass turning. I have also seen some Norway maple (photo) showing significant tint, and even more surprisingly hazel (photo). The latter is often one of the last to still have leaves, so it seems a bit early in the process for it to be starting to turn. But then there are other examples of trees that tint early yet last till the end of leaf fall - sweet chestnut (photo) being one that comes to mind.

I still hold to my cold nights theory, however, and am looking for a sudden turn in the weather - a shift of the wind to a cold direction, a heavy frost, to get us into the final phase of leaf fall. With subtropical air bathing the south east as I write this, that doesn't seem particularly imminent.







27 September 2017 You might have noticed that there is quite a bit of autumn colour in trees and hedgerows now, but it does not necessarily mean it will be an early autumn. It is not at all unusual for there to be this much tinting in late September, but we have a way to go before the final push, the time when all the remaining foliage turns, producing the best autumn colours. Typically that does to happen until well into November.

I have never been able to get a satisfactory answer as to what triggers leaf tint - what makes it happen in one place or time and not in others. One would think there would be a succinct explanation somewhere on the web, but if one exists, I have never found it. Clearly day length and average temperatures have an effect - as the days shorten, leaves turn. But if that were all, then the timing of leaf fall would be fairly easy to predict. Instead it varies considerably from year to year.

One or two factors can be identified, however. Mild, wet, grey Septembers and Octobers do not make for good colours, while sunny days and cold nights definitely do. I have read that the reason New England gets such good autumn colours is partly because the US has some highly colourful tree species, but also partly because it has stable, sunny autumn weather.

Speaking personally I think you have to add in the effect of unexpectedly cold nights. This theory was expounded to me in woodland near Leighton Buzzard by a passer-by one year - that a sudden drop in nighttime temperatures to the low single digits sparks an uptick in autumn colour about ten days later. I have found that works more or less (though if I am honest, not infallibly).

It matters when the cold nights occur, however. If they are in late October or early November, they can trigger a mass turning of remaining foliage - the kind of conditions that produce the best colours. If they occur in September, only some trees and shrubs turn. Typically these include hawthornblackthorndog roselimes (especially ones planted in streets), birch and hornbeam. Apart from hornbeam, all these are showing good colour in places at present.

I stress "in places": and also that by good colour here I do not mean that the trees are fully turned, only that they have reasonable numbers of tinted leaves. Having said that, I have seen some blackthorn and hawthorn that are not only fully turned but whose leaves have gone that lovely gold or maroon colour that they usually only go later in the autumn. Limes too can have a big "frosting" of yellow leaves. But on many trees - birchoaksycamore - you get tinted leaves scattered among the green ones - a flecked effect. Some species - eg elder and ash - only yellow slightly before shedding, or even shed green leaves. You can see this happening right now.

Whatever, the tinted leaves fall and then the remaining foliage continues green until the next cold night (or whatever trigger they respond to). In this way autumn can be rather stop-start. If it is mild at night for the next two weeks then we might well be looking at the green woodlands and hedgerows around us and wondering what happened to autumn. Or it might turn out to be an early autumn after all: nature delights in confounding me.



19 September 2017 March and September have a lot in common in nature terms. Weatherwise, changeable October is probably a better twin for March, but when it comes to flowers, insects, butterflies, both March and September are transition months. In March it can still be very wintry but hints of spring are everywhere. In September you definitely feel it is no longer summer, but it is not quite autumn yet either.

In both months, sightings of flowers, insects or butterflies are occasional rather frequent. You can walk for ages in the countryside and see nothing, but then you turn a corner and see something interesting.

For example, in the past week, while on an otherwise mostly butterfly-free walk, I walked down a sheltered valley and found a buddleia bush - with just a few flowers left on it - that was a positive riot of them. There were at least six red admirals, a small tortoiseshell and a peacock, and two green-veined whites. Nearby I saw one of the very few small coppers I have seen this year, a couple of specked woods, and both of the other common white species (small and large white). It was like stepping back a month.

It is the same with flowers. My practised eye walks down paths and lanes at this time of year and sees whole stands of knapweed or hemp agrimony or hogweed that would have been in full flower three weeks ago but are now desiccated and brown. But just when I have concluded that all flowers are over for another year, I turn a corner and see something still blooming away - some common fleabane, maybe, or some redleg.

My eye is also drawn to the ordinary flowers that one barely notices when all is ablaze in summer. Red clover or daisies lining paths. Dandelions and hawkbits on short grass. Dribs and drabs of birdsfoot trefoilYarrow.

Whether these are survivors from the summer or new growth is an interesting question. I mentioned a few weeks ago that dandelions definitely have a second season in September. You can also see some creeping thistle and ragwort in flower (probably hoary ragwort at this time of year) which definitely are young plants that have grown from seed produced earlier in the summer. In urban corners chickweed undergoes an autumn revival of sorts. Alkanet reappears on rural verges near houses.

With other plants I am less sure. I used to categorise white deadnettle as one of these autumn 'come agains', but I have now concluded it can crop up at almost anytime from March to October. The same is true of smooth sow thistlegroundsel and shepherd's purse in urban corners and herb robert on shady verges. Meanwhile flowers such as common mallowwild carrotfield scabious and black horehound are more like hangovers from the summer, ones that have just flowered a bit later than their peers.

Whatever, some flowers continue to be found until surprisingly late in the year. I used to think September was the end of them but then realised some lasted into October. Each October I swear I will pay attention and record the last flower I see in the year. But sometime in November I forget to look. Perhaps there is always something in flower somewhere in any month of the year. I have not tested that theory properly yet, though.





13 comments:

Em said...

Somewhere on this site you have written that it is perhaps sterile to spend time identifying birds, plants etc but I don't think so. I think it helps enjoy the rich diversity of what is there and appreciate the differences and variety in nature.

Peter C said...

I am glad you think so, and definitely agree!

ramblinros said...

Thank you for interesting nature blog
Found a new-to-me spring flower on Saturday
Spring Beauty - Claytonia perfoliata syn Montia perfoliata -
the stem is surrounded by a curious cup-shaped leaf
Was walking on the North Downs Way eastwards immediately after the Watts Gallery - very sandy -
up a slight rise and then the plant was on both sides of the descending path
for about the next 100m, and then no more
https://www.flickr.com/photos/ramblinros/13649168915/

Peter C said...

Nice observation, ramblinros! I have seen this plant once or twice and I do mention it in April Verge and Field Flowers (http://nature-and-weather.walkingclub.org.uk/search/label/April-verge)….

"Also in the wierd category is spring beauty, a plant of sandy soils which has tiny white flowers in the middle of large round leaves."

…….but it is a rather rare thing to see, so I am glad to hear of your sighting.

PeteB said...

On polling day 7 May I went for a long tramp over the South Downs starting in Lewes and eventually finishing in Eastbourne. At the start of my walk (Book 2 walk 25c Lewes to Glynde) I had just left the golf club car park and started on the path past a water trough where a herd of cattle were drinking and grazing when to my surprise I saw what I am sure was a single red? deer hind grazing with the cattle (it was too large to be a roe or fallow deer). The animal was frightened by my presence and seemed to try to hide among the cattle! I had my camera phone but did not want to start unsettling the cattle and I had a long day ahead so pressed on with my walk. The only deer I have seen before on the South Downs were fallow deer in the flat water meadows. I have never heard of red or sika deer on the South Downs and a web search has revealed nothing. Quite a sighting !

Peter C said...

A very interesting sighting, I agree. Of course, historically red deer were present throughout England but I had always understood that now they only live in places such as Richmond Park. The only other place I have once thought I saw one was in the Lake District. Perhaps you should report this sighting to some relevant association or other. I am not quite sure which. (If it was a butterfly or bird or flower it would be easier to think of suggestions!)

PeteB said...

Did walk 3.20 Sevenoaks to Wesaterham today after bailing out of it early on Sunday because of violent storm. Bluebells already showing well at Ide Hill and should be at their best in 2-3 weeks which seems a bit earlier than usual? Fields still pretty waterlogged in the morning but after lunch at the Cock Inn terrain and woodland trails much drier.

PeteB said...

Did walk 3.20 Sevenoaks to Wesaterham today after bailing out of it early on Sunday because of violent storm. Bluebells already showing well at Ide Hill and should be at their best in 2-3 weeks which seems a bit earlier than usual? Fields still pretty waterlogged in the morning but after lunch at the Cock Inn terrain and woodland trails much drier.

Anonymous said...

I'm glad to learn that Yellowhammers have been detected on the walks this summer (considering their numbers have declined rapidly). I saw some on the Pewsey/Avebury walk recently. They were in a quiet country lane, flanked by tall *all important* hedgerows. I haven't seen this species for years. E.

Peter C said...

I have read that their numbers are declining, but I have to say I hear them quite a lot in the south east. They like hedgerows on farmland but are also heard up on the downs. A lovely song so I hope they don't decline further.

Sandy said...

Fantastic blog - I was particularly interested in the 19 September one about late-surviving flowers. I started noting down flowers still out in Nov/Dec a few years ago - e.g. 24 spotted on 3-4/12/2014 and 27 on 19-20/12/2015. It was astonishingly mild then of course. I don't seem to have any notes from last year but maybe I wasn't out walking at the right time. Look forward to comparing notes later in the year.

Peter C said...

Thanks for your kind comments. Glad you find it interesting.

December 2015 was indeed the weird mild one when all sorts of early spring flowers and even blossom started to come out. But some flowers in early December are not unusual. Before writing the blog I should perhaps have checked my own December Flowers page which lists several. See http://nature-and-weather.walkingclub.org.uk/2011/12/november-hedgerow-and-flowers.html

Peter C said...

I don’t know why the link in the last post says November in its url. But go to the main blue button menu above the Nature Blog and click December and you will find the page I mean.

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