Autumn arrives early at Minterne

By Sue Hendey BBC Dorset

Some of the leaves which are already changing colour, do not usually go through this process until late September

The head gardener at Minterne Gardens believes autumn has arrived three weeks earlier than last year.

Iain Davies explained that the leaves on many of the trees at the gardens, in Minterne Magna, are already turning various shades of red and yellow.

He thinks it has happened because the wet summer has waterlogged many of the plants.

He also claims that if the following months remain frost-free, the autumnal colours could last longer than usual.

Head gardener Iain is predicting a long autumn with "plenty of colour"

The science

Iain said: "Plants and trees take up water from their roots and they take in sunlight and carbon dioxide from the atmosphere.

"They do this to produce sugars - starches and carbohydrates.

"This happens all year long - the process is called photosynthesis.

"Photosynthesis can't happen without a pigment called chlorophyll, which makes all of the leaves on the plants and trees, green.

"As autumn comes along, the days get shorter, we get colder nights and traditionally what happens then, is the tree or the plant decides to shut down.

"As it does this, against each leaf it creates a cork-like membrane.

"So, gradually it stops using photosynthesis in the leaf to create sugar.

"Once the leaves close down they begin to change colour."

Iain started to see colour changes from the second week in August

There are over 200 mature maple trees within Minterne Gardens and these are just one of the species which has already started the autumnal process.

Iain said: "The maples trap sugars within their leaves.

"Once the leaves close down, if they've still got sugars trapped in them they turn lovely purple and red [colours], which we have just started to see happening now."

Unexpected colour

Iain explained that he started to see colour changes not just in Dorset, but across the whole of the country, from the second week in August.

He said: "I travelled through quite a lot of gardens up and down the country, and I was seeing some of the larger, mature trees in the hedgerows and fields starting to change over - a lot of yellowing started happening [to the leaves].

"Within the garden here, I started to see the cercidiphyllum [a species of tree native to Japan and China] beginning to colour up, which is quite unusual really.

"You wouldn't expect this to happen until late September."

The blue bird rhodedendron "should not be flowering at this time of year"

"Waterlogged"

Ian believes the "excessive" rain during the summer months could be the cause of the early autumn this year.

He said: "I believe the plants, particularly the larger trees, are absolutely waterlogged.

"Since we've been watching the climate situation this has happened five or six times in the last 10 years, so perhaps this is the timing that we're going to have to get used to!

"[As a gardener] I think you have to look at each season as it comes.

"We can plan certain things - I mean, with bulbs we can plan when we're going to put them in.

"And if the season comes earlier or later, bulbs tend not to worry us too much in a garden like this.

"But it can cause a problem with pruning.

At the moment, for instance, there are certain things [plants and trees] which are still in flower and traditionally wouldn't be.

"We really need to get in and prune them, but we have to wait until they've finished flowering."

"Totally unheard of"

Magnolias, Guernsey lillies and many of the dwarf varieties of rhodedendron, like blue bird, have re-flowered at Minterne Gardens.

Iain feels this shows that the plants are "as confused as we are" as to what time of year it is.

He said: "The Christmas cheer rhodedendron, as the name suggests, should really flower from Christmas to Easter, but I've got some in the garden now which are coming into quite a good display.

"It's totally unheard of at this time of year!"