Magnolias and Climate Change at Caerhays?
In this absurdly early spring where the magnolias first started coming out on 2nd January, at least a month before all known records, and two or three months before ‘normal’ it is time to reflect on this abnormality. What can be stated with certainty is that since the first Asiatic magnolias introduced by Wilson and Forrest began flowering here in the 1920s and 1930s we have seen nothing like it.
At the time of writing this, 8th February, we have seen only one morning of very slight frost at Caerhays for the winter. Apart from 2012 this is not however that unusual in the last decade. We have witnessed a near continuous mild westerly airstream since November with repeated gales and much higher than average rainfall.
Last summer was reasonable in June and July turning wet in August. Until early November autumn was dry and sunny with the leaf remaining on the trees well into November and well into December as far as magnolias were concerned. Several young magnolias still have old leaf on today.
As my daily garden diary records around two dozen magnolias had some flowers in September through to November. Secondary autumn flowering of magnolias is not unusual although few people notice flowers amongst leaves. What is now clear is that a few of these flowers, especially on a young Magnolia ‘Caerhays Belle’, were not secondary blooms but spring arriving in the autumn. These plants now have no buds left for ‘spring’.
Today there are nearly 50 tree magnolias in full flower. We normally expect the magnolia season to be at its best around 20th March. This year, barring frost or cold east winds, it looks like 15th February which is a week before the spring gardens formally open here.
We are fortunate to have a garden diary, written by my great grandfather, great uncle and father, covering events in the garden going back to 1897 on a daily basis. All this information is now readily available online as part of my own continuing daily pictorial garden diary.
What this reveals is extremely interesting. In the overall context of 130 years the magnolias may well indisputably be ridiculously early. However this is by no means true of other plant species:
- Camellias flowering in general and, in particular, the very early pre Christmas x williamsii camellias such as ‘November Pink’, ‘St Ewe’ and ‘J C Williams’ are almost exactly on time and as usual. The diary proves that camellias have been out much earlier than in the last three months. Indeed in 1972 the family picked over 80 different camellia varieties for the house on Christmas day. It would have been difficult to get to such numbers last Christmas.
- The early rhododendron species and hybrids are appearing exactly when one would expect them to after a mild winter and cannot be considered ‘early’ either although many of them will never have witnessed magnolias in flower beside them. Rh moupinense, Rh mucronulatum, Rh delavayi and even Rh ‘Cornish Red’ are out on time. Other rhododendrons which we might have expected to be early such as Rh ciliatum and cilpinense are still in tight bud.
- Much is made of the harbingers of spring; the snowdrops. Again the diary can readily demonstrate that they appeared exactly on time at Caerhays on around 10th January. They have often been earlier and are now, as usual here, going over.
- The newspapers are full of stories of ‘early’ wild flowers and especially primroses and wild daffodils. However the diary proves that, cold winters with snow aside, this year is by no means exceptional or record early.
Folklore and former head gardeners at Caerhays have argued that a cold snap vernalizes camellias and snowdrops into flowering action. I believe that there is some evidence for this in the diary in years where there was more severe frost in November and December (eg 1919 and 1947) but currently nature is arguably adopting its normal routine after a mild winter.
Magnolias are therefore arguably the exception although we can all find a few other things to undermine this contention. For instance the Spanish bluebells here are already 10 inches high out of the ground and a flower before the end of February seems a possibility. The evergreen azaleas are also indeed very early into flower.
We read of doves nesting on the south coast but I have yet to hear a spring dawn chorus as the weather continues wet and blustery.
So is this climate change at work and are some of our plant species adapting to it by flowering increasingly early? I do not think so!
The diary faithfully records the flowering times of several southern hemisphere plants introduced here over 100 years ago. In the 1920s and 1930s lapagerias from Chile flowered in November, December and often on into January. Eucryphias from New Zealand, Australia and Chile historically flowered in the autumn. Today we would think of both as late summer displays. Leptospermums would be in the same category. It is certainly demonstrable that these species have indeed adapted to our northern hemisphere timetables in their flowering periods. This is a change of climate but not ‘climate change’ as such!
Before and after the First World War there were many more very cold winters than we have seen recently. Nevertheless the diary often records 20 or 30 species of rhododendron flowering in December in milder winters with plenty of records of sprays being cut for the house. There are plenty of years when fuchsias and even geraniums as well as roses still had flowers in December and even January. Magnolias, of course, did not exist then as we know them today but Magnolia stellata, planted in 1895 beside the house, was occasionally out in February.
Magnolias aside what we are seeing is historically not that exceptional. Indeed, as we saw in 2012, a cold snap quickly puts the flowering timetable back to what we remember in much of the 1970s and 1980s. The Chelsea flower show in 2012 saw us exhibiting many plants on the Burncoose stand in late May which had been long over after milder winters.
One might well argue that since Asiatic tree magnolias originate from the Chinese provinces of Yunnan and Szechuan at 6-10,000 feet on high mountain forests they are probably very likely to bloom much earlier in our mild Cornish woodland climate. In the wild magnolias are pollenated by wingless insects so why should they not respond to the availability of the flies, bees and other insects seen in the garden this January?
I conclude that the garden is mainly flowering normally and on time after a very mild winter with magnolias being the aberration. One perhaps uniquely mild winter has to be set in its historical context especially as all the magnolia flower will probably be crucified by cold easterly wind and or snow before this article is even read.
The point is however to encourage argument, debate and more examples to contradict what is a topical and controversial issue with no obvious correct answer.