Blackthorn Weatherforecasting

Blackthorn Blossom

For the past two weeks, almost since the March equinox, the Blackthorn has been increasingly floriforous around here. It is a ghostly presence in the hedges, with its white flowers growing along the smaller branches and tops of Prunus spinosa trees, leaving their black trunks bare underneath – almost like the child dressing up at Samhain with black leggings and a white sheet over their heads. Yet the hawthorn which makes up the bulk of the hedges around here is now glowing green with fresh young leaves, creating a patchwork effect.

The old saying for this time of year was “Beware the Blackthorn Winter.” With high pressure dominating and the weather having turned beautifully sunny and warm for much of the country, I have felt that Spring has finally sprung – yes there is the occasional nightly frost, but nothing particularly long lasting since most days it has gone within an hour of sunrise. So I have been puzzled as to why Blackthorn blossom should suggest a return to winter, and decided to investigate further.

Patchwork of white Blackthorn and green Hawthorn

It turns out that normally the blackthorn flowers at the middle to end of April – when there is very often an unexpected cold period. This year winter has been mild, and the weather seems to be continuing that way, so I am thinking this has caused the blackthorn to be particularly early. It is not alone; bluebells have been flowering since the beginning of April around here, 3-4 weeks earlier than normal. But the result of this is that the Blackthorn is not coinciding with a cold spell as it usually does; MET office forecasts are currently predicting ‘rain or showers, turning wintery’ ie snow for next weekend…

I now await confirmation from another tree for my planting out, using that other favourite saying “Ne’er cast a clout ’till May be out.” It refers to the hawthorn blossom, which is usually in flower in mid-May around here – and has generally proved a reliable guide to the last frosts (provided I wait for my own hedge to flower rather than those in more sheltered locations). It already has flower buds, but as I have seen before, the tree is happy to keep its flowers in bud if necessary until the cold weather is over. Wise old trees!

Bluebells

Bluebells in once-coppiced woodland

Bluebells in once-coppiced woodland

In a beautiful demonstration of succession, this is the same patch of woodland as the wild daffodil photos I took at the end of March.

They are a little more spaced out than elsewhere in the wood, and therefore slightly less of a blue haze (even allowing for the less than ideal light conditions) – I presume this is because they are sharing the rootspace with other bulbs.

Bluebells in Silver Birch wooded area

Bluebells in Silver Birch wooded area

It may also be because they prefer different conditions – these two photos are from another area with silver birch and hazel rather than beech and sycamore. (Click for larger images.)

Bluebells by hazel tree

Bluebells by hazel tree

Surveying Wildflowers

View of linear plot

View of linear plot

For eleven summers now, I have surveyed a tiny area of Derbyshire for Plantlife‘s Common Plants Survey. My randomly allocated square is not somewhere I would normally choose to walk, being the wrong side of a dual carriageway from here, but it has proved very interesting to return to the same small area over such a period of time, and chart the changes. I now think of it as ‘my’ square, so while I could swap to somewhere closer, as this year the survey undergoes massive changes, I decided to stay put. In its favour are well-kept footpaths which go through the exact centre of the square, and a small patch of woodland filled with bluebells in late spring.

The survey has changed twice since I started: originally there was a list of 65 plants, and I would check for their abundance within three specific areas – a square plot in the exact centre of the square, a linear plot nearby, and I chose to survey an additional linear plot that was along a particularly interesting bit of hedgerow. The list was then extended to 99 plants, and instead of the ‘habitat plot’, a footpath was followed North-South through the whole square to simply see what was present. I had the option of being a ‘super surveyor’ and listing all the plants, but 99 seemed to be a good number to get to know. Given that for several of these years I had health issues, or was pregnant, or had a baby in a sling, simple was good!

This year the survey is changing again, as a transition to relaunching next year to create something far more in depth, giving hopefully robust data that can be used to monitor how our wildflowers are changing over time. The list has been expanded to 400 plants, and includes common native species, those that are specific or indicative to particular types of habitat, and some invasive species. Habitats plots are back, centre plots are out (I suspect many were difficult to access), and the path idea remains.

One plot I am surveying this year remains in almost exactly the same location as the previous ten years – my original centre linear plot, which runs between the footpath and a stone wall. It is now 25m long not 20m which makes sense, and I have moved it up 2m to avoid a patch by the gate that has been mown since the nearby derelict farm buildings were converted into houses, but these seem like minor tweaks. The field the other side of the footpath was originally surveyed (or rather, a 5x5m patch in the corner was) and I have seen it change from clover in the first few years to arable crops, this year barley. However apart from occasional pruning of the overhanging oak trees, the linear plot gets very little attention and as a result it has become a riot of colour in early summer. Besides grasses, the main plants are stickyweed, cow parley and hogweed with occasional nettles and brambles, but to fill in the gaps there are poppies, chamomiles, speedwell, plantains, vetches, and this year for the first time I spotted Geranium dissectum.

Moving onto the path, this being a transition year there is an increased list of plants to spot but no booklet yet to confirm the identities, nor a simple list to tick off what I could see. So I took a different approach and wrote down every plant I could identify. Given that M’s concentration span wouldn’t allow me to look up plants in situ, I then took photographs of anything I wasn’t sure about and spent the next few days going through them and identifying as many of the remainder as I could. Some of course are not on the list for monitoring, and some will need the second visit for additional identification information, (either because there are similar plants that I didn’t get enough details to distinguish between them, or because they weren’t in flower yet) but how much more I learned by doing it this way! I have added at least half a dozen plants to my knowledge which I now feel I could recognise again, plus I am just starting to explore a whole new world of grasses – quite important on my path since around half of it is through fields that are only occasionally grazed by cows.

The middle section of my path runs through the woodland – which has just been taken over by a new owner who has removed alien invaders like Himalayan Balsam and planted many new trees. However, not all of them have plant labels, and from those that do there are some very interesting and unexpected additions, including 37 different native species according to the notice on the entry style so my identification skills here will be developing as well! Unfortunately the intensive management renders the woodland fairly useless for monitoring purposes, but how fascinating to watch!

And the remaining path? This runs along the side of an access track and has fairly different plants to the other sections, although by no means everything that I know is to be found within my square. However one new exciting find for this year was an pyramid orchid, just a solitary flower seen along this section and not yet open. I hope for some more by next year. So my list for the path is up to 63 flowering species, plus grasses, plus probably some sub-species of yellow flowers that I have lumped together (various sow thistles or hieraciums for example, not in the official list) giving me a starting point for future comparisons.