Contrary to popular myth I don’t spend my days wandering happily around the arboretum looking at trees but grab opportunities as they arise between less glamorous jobs like business planning and budget reviews. Today I had just an early window of opportunity and decided to retrace the route of my first autumn blog almost a month ago. The colour is now really intense and widespread with hotspots like Acer Glade at their peak.

All around Circular Drive acid-loving plants such as azaleas, witch hazels (Hamamelis) and Enkianthus are putting on a great show.

Of the latter genus, the less common E. perulatus on Duke’s Cut path is a showier autumn star. Its bright scarlet leaves always seem to outshine those of E campanulatus (yellow to red leaves) that can be seen in many parts of the Old Arboretum and Willesley Drive.

At the very northern end of Savill Glade, leaning over the path, a young snowdrop tree (Halesia Carolina) can be seen. Most of its leaves are gone but the pear-shaped, 4-winged fruits are still there.

I took a few general shots as I walked around to give an impression of the level of colour. The pair of weeping Japanese maples near Duke’s Cut Gate were doing their usual firework impersonation and Colour Circle just needed a Victorian carriage and party of picnicking Holfords to complete the picture!

Two interesting trees just beginning to colour were ginkgo (Ginkgo biloba) and (at last) the group of dawn redwoods (Metasequoia glyptostroboides) at the western end of Pool Avenue.

My most surprising encounter was with some impromptu leaf-art! I love this and can’t help wondering who the anonymous artist is.

Like much of this week, today was very murky and my pictures show that. But the forecast for the weekend is for colder, brighter conditions and my advice would be to get here soon while leaves last!

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It is the group of Euomymus oxyphyllus along Loop Walk that signal to me that autumn is on the way as they tend to start colouring in September.

“It was at this season that Sir George and Lady Holford especially loved to have their gardening friends with them, and the ‘colour parties’ have for many autumns past been an institution at Westonbirt.”
(Trees & shrubs at Westonbirt, 1927, AB Jackson)

Archive image of Acer Glade

My main job is to manage the information on our current collection of specimen trees and shrubs – what are they and where are they.

This information is made available to the public via the interactive map.

Along with a team of volunteers we try to keep the specimens labelled.

I occasionally work on our reception desk and get a short spell of being asked ‘What will the autumn colour be like?’ and ‘When is the best time to come?’

Our general rule of thumb is that the best time is the last two weeks in October and possibly into November.

Can I put together what I know from the information I am sent from the Met Office and the information in the Westonbirt archives to help answer these questions?

The Holfords no doubt knew when to invite their gardening friends as the Westonbirt Visitor book for 1922 shows.

Westonbirt Visitor book for 1922

The first three signatures Bean, Balfour and Jackson were definitely important ‘tree’ people. And the dates 17 -19 October would tie in with the thoughts of the ‘curator’ Mr W J Mitchell on the best time for autumn colour.

Mr W J Mitchell: centre back in this picture

W J Mitchell noted 16 October as the on average the best time for colour and was constantly wondering what affected the colour. The general feeling being that sunshine was a factor. Following a hot dry summer:

“The autumn coloring of 1928 was exceptionally good but disappointing in that they last so short a period. The opinion was generally expressed that they were probably quite a week earlier
than is usual. Sunday October 7^th was undoubtedly the best Sunday …One other tree I must specially mention that is Parrotia persica, they were so good we called it a Parrotia year.”
(Mitchell notebooks 1927 to 1947)

Archive photograph of Parrotia persica on Willesley Drive

Parrotia persica in autumn leaf

The leaf colour can range from yellow to purple with all the ranges in between.

What might this year’s weather forecast?

We have wide variety of plants at Westonbirt from different parts of the world. So it is likely that they will tolerate and even thrive in different types of weather.

W J Mitchell notes that Parrotias (Persian Ironwood) like the sun but Cercidyiphyllum (Katsura) and Acers on the whole prefer wetter conditions.

So this year I would expect good colour from the Acers and not so good for the Parrotia.

From what I have seen so far individually the Acers have been glorious particularly the reds. Follow Director Simon Toomer’s blog to see how these are doing.

One thing I look out for as autumn progresses is the larches in Maple Loop. They have done their job of providing gentle shade for the Acers and give a splendid display themselves as the leaves turn to yellow.

Japanese Larch

“Autumn 1939. Because of the dull summer we did not anticipate a very good season for the autumn colouring this year, but on the whole it has been magnificent”

“Autumn 1946. The earlier colouring trees and shrubs like Acer saccharum, rubrum japonicum ver: vitifolium, prunus Sargentii
euonymus oxyphyllus and planipes were exceptionally good this autumn, … there was quite a fine show, but quite a fortnight later than usual. The dull summer, wet August and September was the cause of this. Frost was negligible with the exception of one or two mornings in October and there was a fine show of colour until well
into November.. On the 6 Nov: the colouring was extraordinary for what we think so late in the season. In fact in some notes I made on this date, the whole place was still quite beautiful and much colour remaining. On the 10^th of Nov: Acer Davidii …was a mass of yellow and Acer Maximowiczii a mass of tangerine, a fascinating shade and wonderful. The old trees of Acer griseum just starting to turn.
(Mitchell notebooks 1927 to 1947)

Acer Davidii

Given that we are probably generally later now due to a general rise in temperature, we might expect the colour to run well into November. But that depends on the wind and frost.

But what about other times of the year?

Spring

In fact my favourite time here is the spring with all the different colours of the new leaves. Like those in Lime Avenue:

Lime Avenue

“Acers, cercidiphyllums- In their spring state to me thy are as beautiful as in Autumn, the Many and varied shades of delicate greens, bronzy reds and purples are always very much admired and justly so. No other family of trees or shrubs can approach the Acers in spring,”
(Mitchell notebooks 1927 to 1947)

Japanese Maple collection

What might the future impact of this years’ wet weather be?

The warm and dry April and the subsequent rain has meant that rhododendrons in particular have put on good growth.

A good example being the Rhododendron smirnowii planted this year along Circular.

 The seed for these plants were collected in Turkey by our propagator Penny Jones in 2005. Also in the same area is Rhododendron ‘Daphne Millais’ propagated by layering.

“Summer 1936 proved to be the wettest July at Westonbirt since a record has been kept 1888. … moisture loving plants found it very much to their liking and such things as rhododendrons and conifers simply revelled. The maples also found it to their
liking, they made exceptional growth, and if we get a good autumn for colouring they should be very fine.

The rhododendrons and azalias also enjoyed all this moisture immensely, especially the atmospheric moisture and made marvellous growth. A fine autumn to ripen this growth and they
should be a sight next spring.”
(Mitchell notebooks 1927 to 1947)

So we could be in for a splendid spring in 2013. Fingers crossed for a mild winter.

“Spring 1937. The idea, which for so long has been prevalent, that a sunless summer would be followed by a flowerless spring, has been proved this year to be quite incorrect. Yet the spring of 1937 was as floriferous as the spring of 1936, which was preceded by a very hot and dry summer.

So another of the old ideas has been proved a fallacy. Some day some interested scientist will perhaps discover for us what essentials are needed, other than sunshine and ripened wood to produce floriferousness the following year, we have always thought these two essential, that they are not necessary has been proved to the hilt this year.

The ornamental cherries have never flowered more freely …but the most spectacular thing of all was Davidia Involucrata …it has never flowered with such prodigality before, and the name of the Ghost tree which one sometimes hears it called was this year an appropriate one, as it appeared almost ghostly in its whiteness.

 The Azalias were masses of bloom and very much admired. It will probably be years before the Rhodos and Azalias flower with the freedom they have this year, .. Magnolias were grand and lasted for weeks.”
(Mitchell notebooks 1927 to 1947)

Davidia Involucrata

Main Drive in the Holford era used to be called Rhododendron Drive. I can imagine Sir George taking one of his visitors, even a royal one, for a drive around the arboretum.

Main Drive

“14.5.44   Their Majesties Queen Mary, Queen Elizabeth and the 2 Princesses, Princess Elizabeth and Princess Margaret came today. The azaleas were at their best and some of the earlier rhododendrons were also very fine The Magnolia above Ponting’s Box, was magnificent and very much admired by the Royal Party.”

A Royal visit to Westonbirt

Not all the colours at Westonbirt are provided by the flowers. Sometimes our visitors bring us some.

A visit to Westonbirt by Awaz Utaoh

And sometimes we add our own…

Treefest, August 2012

Useful links
Find out more about autumn at Westonbirt
Use the interactive map
The history of Westonbirt Arboretum

For today’s blog I decided to headed up Willesley Drive to see how some of the trees I looked at last week had changed. We’ve had a few cold nights so I was expecting quite a bit more colour and that was certainly the case.

 
Close to the old craft shelter (you’ll see this marked on the map in your Autumn Guide), a mature hickory stood out from the woodland behind. All over the arboretum, the bright yellow leaves of the hickories have lit up during the week.

 
To the south of the drive, just before the entrance to Sand Earth, the young paper-bark maple (Acer griseum) was just beginning to turn its usual bright red. This is a truly all-year-round species thanks to its rusty red flaking bark that looks particularly fine on a sunny late autumn or winter’s day.

 
I took a dip into Sand Earth to look at some of its unusual species. Almost immediately I was confronted by the spectacular sight of a cherry birch (Betula lenta) in full autumn colour with the sun streaming through the foliage. I later saw others in the link and all of them were at about the same stage.

 
Further into Sand Earth I spent a few minutes trying to photograph a young golden larch (Pseudolarix amabilis) as it was buffeted by the strong breeze. Tripods are great things but not much use when the branches are waving around – excuse the shake! This rare deciduous conifer from China really lives up to its name with its whorls of golden needles.

 
Tree work around the arboretum produces a lot of woodchip and the tree team use it to mulch both young and mature trees. As well as suppressing weed growth and protecting surface roots, it creates a nutrient source for a wide variety of fungi. After damp weather (and we’ve had plenty of that) these mulched circles often become fungal ‘carpets’. I took this picture of young puff balls just about ready to waft their spores on the breeze.

 
Crossing into Palmer Ride I came upon a young maple showing spectacular colour. Acer diabolicum gets its strange name from the fact that the winged fruit have little horn projections – hence the devil or diabolical reference. Trees of this species are either male or female (not both) but in any case this individual is too young to fruit. I have seen and collected it in Japan in forests around Mount Fuji where its colour is as intense as any of the maples.

 
From Palmer Ride I took a short cut back through the coppice woodland. The native shrubs including spindle and wild dogwood were putting on quite a show of their own but the thing that really caught my eye were the bright ruby berries on the guelder roses.

 
Just before reaching the valley bottom gate on the edge of the Downs, the dank mossy trunk of an old oak can be seen providing a home and source of nutrition for sulphur tuft fungus. This species takes advantage of dead wood and can provide a useful clue to decay in the trunks of old trees, particularly where they are close to busy paths or buildings. This one is in a quiet location and can go on providing a valuable habitat for fungi and a host of other deadwood species.

So where are we on the colour ‘thermometer’?  It’s not at peak intensity yet but is certainly advanced enough to make a trip well worth while. For the next two weeks it’s going to be truly gorgeous. Let’s hope for more good weekends!

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Keep an eye on autumn colour and share your images of this autumn at Westonbirt on our Facebook page

After a glorious weekend of sunshine, I stepped out into Silk Wood on a dull, overcast afternoon to take the leaf colour temperature. 

The relatively calm and mild weather over the last week has meant that the leaves are turning in a steady drift rather than a sudden rush.

The Persian ironwoods (Parrotia persica) are probably the most prominent species at the moment with the large clump in the valley bottom standing out like a beacon as you walk down the slope towards Waste Gate.

The beeches on the Downs are also developing tawny outlines as their outermost leaves are the first to turn.

Just inside Waste Gate the clump of red dogwoods (Cornus alba) are just beginning to turn with some stems well ahead of the rest.

On the opposite side of the path a tupelo (Nyssa sylvatica) has burst into colour with another bright ironwood in the background. I love the colour and shape of these trees though the former tends to be disappointingly shorted-lived.

Cherries tend to be under-rated when it comes to awarding the prizes for autumn leaf colour. They also vary greatly from one year to the next and I certainly didn’t expect this damp cool summer to suit them. However, this Sargent cherry (Prunus sargentii) on Waste Bank was certainly confounding my prediction with gorgeous shades of orange and pink, even in the dull light.

Further down Waste Drive at the junction with Broad Drive stands one of autumn’s most reliable extroverts. This mature Cappadocian maple (Acer cappadocicum) is half butter yellow and half green. The leaves don’t hang around long once they turn and leave a ‘pool’ of yellow around the trunk.

Maple Loop is warming up nicely but most Japanese maples are still green. The picture I took from close to Oak Avenue shows some trees turning but within most of the loop the colour is less advanced.

At the junction of Broad Drive and Willesley, I had a close look for the illusive fruits of the bladder nut (Staphylea x coulombieri) that grows there. The strange 3-chambered ‘bladders’ blend in with the leaves and it takes a while to get your eye in.

Along the edge of Willesley Drive you can see two yellowwoods (Cladrastis kentukea) from South Eastern USA.

Their name describes the colour of their wood but could equally apply to the leaves. In the early stages of colouring they take on a delicate green-yellow variegation that picks out the structure of the leaf veins.

One tree I had expected to be colouring was swamp cypress (Taxodium distichum). We have a number of these deciduous conifers in the Concord Glade area and all are remaining resolutely green! Perhaps by this time next week they will be on the turn.

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It’s a week since my last autumn blog and I took another walk around today to see how the colour is progressing. Things have certainly moved on a quite a bit but as always, the eye tends to focus on the trees that are colouring while all around them most are still showing little sign. I really like this time when trees are still full of leaf but with the first signs of autumn around the edges.
 

One thing to remember is that at this time of year it’s easy to mistake signs of stress or illness for early autumn colour. Many of the earliest turning Japanese maples for example are actually suffering from honey fungus or other ailments. Leaf blotch on horse chestnut caused by the fungus Guignardia aesculi likewise can look like early colour but the tell-tale yellow band around the brown blotch gives the game away.

In Colour Circle I was greeted by the beautiful sight of the red-yellow combination of Persian ironwood and Amur cork tree (Phellodendron amurense). The former is a very old tree possibly dating back to the Holford era.

On the opposite side of Colour Circle, the group of Katsura trees is largely green still but one or two individuals are beginning to turn – this one has turned butter yellow but elsewhere in the arboretum you can see the usual sweetshop mix of purple, red and gold.

I’m always fascinated how some species change colour very irregularly with both green and coloured leaves simultaneously on the same branch. The rare Acer pseudosieboldianum from Korea often does this. Shame it doesn’t have a more spellable common name!

Another rare maple, this time from Japan, is Acer nipponicum. The species is not particularly known for autumn colour but this one close to Victory Glade stood out from the green crowd.

And now for surprise of the day: The handkerchief tree (Davidia involucrata), best known for its spectacular late spring flowers can sometimes conjure-up an interesting combination of autumn tints. I can’t describe these adequately so I won’t try!

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Keep an eye on autumn colour at Westonbirt on our Facebook page

Not wanting to miss out on the first signs of autumn colour, I ventured out of my office for a stroll round Circular Drive today to see what I could see.

These are early days with most trees showing little or no sign of autumn.

Those species that are turning tend to be natural early colourers or those that haven’t enjoyed the weather conditions this year and have decided to ‘pack up and leave early’.

Spindles are always early to colour and this year is no exception.

Many of the winged spindles (Euonymus alatus) are already looking a bit sparse and bedraggled, displaying a distinct lack of colour sense with a combination of orange fruit and bright crimson leaves.

Skulking in the shade close to the northern end of Sir Georges Walk and overlooked by most passers-by lives the arboretum’s best example of Disanthus cercidifolius.

I’m always amazed that nobody has come up with a common name for such a lovely shrub. I was drawn by the colour of its Judas tree-like leaves (hence the name), already turning deep wine-red. If you look hard you can also see the small spidery flowers.

One of the surprises on my walk was to see the epaulette tree (Pterostyrax hispida) showing both yellow leaves and the dried remains of its summer flowers – perhaps even more epaulette-like than ever.

And for rarity of the day, Sinowilsonia henryi takes a bit of beating. Not usually considered an autumn stunner, this plant was backlit by the low afternoon sun and made me think again about what I have always thought to be a slightly dull species.

I will be taking regular strolls through the arboretum during the autumn season and will report back on the state of play: the stars and the also-rans, the slow burners and those that come and go in a flash.

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Keep an eye on autumn colour at Westonbirt on our Facebook page

As the summer draws to an end, I always start to think about our annual planting programme.

Each year we add around 300 new trees and shrubs to the collection, the vast majority of which will have been grown here at Westonbirt in our very own Propagation Unit.

Finding a suitable location where a particular plant will hopefully be happy ever after, soil and light etc…, is always an enormous challenge. But to complicate matters, I also have to consider the role every new planting will play in our historic landscape. Ensuring that the ‘picturesque’ style, for which Westonbirt is best known around the world, will be enjoyed by the next generations takes a lot of careful thought.

The other day I happened to be thinking about good places for autumn colour around the arboretum, and began trying to imagine which trees will put on the best display this year.

This brought home just how important it is for me to get these new specimens in exactly the right spot, as very often it is the variety of foliage, colour and shape of the surrounding trees that really enhance our most visually pleasing autumn favourites.

I have gained huge respect and admiration for the foresight of the arboretum’s founders, Robert Stayner Holford and his son Sir George, as it is their original layout that continues to produces such spectacular scenes throughout the seasons.

The Arboretum Landscape Plan begins with this quote from R S Holford’s obituary in the Wiltshire and Gloucestershire Standard (27 February 1892): “…the wonderful collection of trees and shrubs for which Weston Birt is so famous in the botanical world, were formed by Mr Holford … and will be a lasting memorial, not only of his wide knowledge, but also of his almost unerring taste as a landscape gardener.”

It will soon be time to enjoy the autumn in full glory, for yet another year.

Images, L-R: Westonbirt’s new propagation unit; Westonbirt in October 2010; Robert Stayner Holford

Useful links
Keep an eye on autumn colour at Westonbirt on our Facebook page
Find out more about Westonbirt’s picturesque landscape

Autumn is a spectacular time of year at Westonbirt. This photo-packed blog will take you through the weekly highlights of what’s looking good and where. Photographs featured here have been taken in the few days prior to publication. Visit the Forestry Commission website for more information about what’s happening at Westonbirt during autumn.

This week will be the final Autumn Colour Watch Blog for 2011. That is not to say that there is not any autumn colour to see – the oaks are still clinging to most of their leaves as I write, as are many of the Persian ironwoods and Euonymus. But autumn is certainly past its height now and thoughts here are turning to winter and our Enchanted Christmas event.

In the Old Arboretum, there are some interesting plants still hanging onto their leaves. Pictured above are Acer pectinatum ssp. maximowiczii, (which doesn’t conform to our idea of the palmate leaves of most maples), Enkianthus perulatus, and a Japanese maple which has still got green tips on the leaves.

Over in Silk Wood, Maple Loop looks surprisingly unchanged at first glance – there are perhaps a few more bare branches, but as you can see, there are some lovely yellow, orange and red leaves still glowing in generous abundance. We will have to see how this situation progresses, as so far we have avoided the frosts that will probably bring this display to an end.

Bare branches, however, do not mean an end to bright colours in the arboretum. The interim period between autumn and winter offers some interesting contrasts – a tree in full leaf acting as a backdrop to another that has completely dropped its leaves – and gives the spotlight to plants that might be less noticed during the rest of the year, such as the glossy red stemmed willows that you’ll see in the car parks. These continue to provide welcome colour during the winter months, as do the dogwoods, which currently contrast with bright yellow maples, but are equally striking against an dark yew background.

And then of course, there are all of the wonderful and varied barks (I’ve been led to believe that the pursuit of barks is called ‘barking’, but I’m not entirely sure this is an official term…). The range of colours is amazing – amongst the Acers alone there is wonderful variety, from papery rust red to smooth stripy green. Birches again have vast variety, both in colour and texture. I was pleased to rediscover the bark of Stewartia monadelpha. This genus of plants became a favourite of mine through the spring and summer months, with its photogenic buds and flowers, and now, in bare branch I still say it is difficult to take a bad picture of it. Wonderful!

So, the Autumn Colour Watch Blog may be over for another year, but that certainly won’t stop me continuing to explore Westonbirt between now and the spring – I hope you feel the same! My colleagues and I will continue to add our images to the Facebook page, so keep an eye on that.

Useful links:
Enter our Inspired by Autumn at Westonbirt photography competition
Directions to Westonbirt Arboretum (our postcode is GL8 8QS)
Buy tickets to the Enchanted Christmas
Visit the Autumn Colour Watch Blog archive
Find out about Friends of Westonbirt Arboretum membership. It is great value!