Three Hogweeds

For no other reason than they caught my eye and interest across the year.

First up in July, this curious mutant of Hogweed (Heracleum sphondylium subsp. sphondylium) with foliaceus bracteoles.

In October, just as we had our first frosts, I found this attractive pink flowered plant. I have never seen a pink form in this location before, so I wonder if temperature influences flower colour. Even if it does, some pink forms definitely have a genetic basis, and one is currently being marketed as 'Pink Cloud'. Does the colour elevate it to garden worthy? I'm in two minds, one part of me is curious to grow it, the other is shouting don't be stupid why on earth would you want hogweed in the border.

Finally, in November I found this plant pushing up to flower. It was a little too robust to be Hogweed, and the intermediacy in stature, foliage and pubescence indicates a cross with Giant Hogweed (Heracelum mantegazzianum agg.).

Unusual Arums

Back in late winter (just before the year took a strange turn) I found a large stand of an unusual looking Arum under trees along an old track near Mickletown (VC63). It was in full leaf and yet there were no others around either here or locally, which struck me as odd. It seemed far too early for Lords-and-Ladies (Arum maculatum) to be both up and so far advanced. My gut feeling was it had to be the unmarked form of Italian Lords-and-Ladies (Arum italicum subsp. neglectum) but I wanted to see it in flower to be sure, something I was not able to achieve despite regular trips over spring and early summer (frustratingly, come October I realised it must have flowered as there was one fruiting stem). The leaves looked a good match to some images online but not enough for me to be certain. Perhaps relevant to this, I later found out that early season foliage differs in shape from late season foliage. The following photos were taken in April 2020 once Lords-and-Ladies had emerged, the pale veins of the Italian Lords-and-Ladies were quite obvious when compared against the former.

With that in mind, the next thing to do was go and look for it this autumn, as this would clinch the identification. So in October with the marked form of Italian Lords-and-Ladies (Arum italicum subsp. italicum) popping up all over the place I went for a look. Annoyingly there was no trace, but all was not lost as subsp. neglectum is reputed to emerge later than subsp. italicum. By the time of my second trip in early November it was just emerging. A good result, case closed. 

The only remaining question is how did it get there? Yorkshire is far outside its native range. While it could be an escape from cultivation it is a relatively obscure one, even in a county with more than its fair share of unusual escapes - if it can be grown in Yorkshire you can be certain someone is somewhere! I can't think why anyone would specifically choose this species, short of there being an Aroid fanatic living in Mickletown. There is perhaps a slim possibility that it came in with daffodil bulbs originating from a grower in South-West England, as the margins of this track support a diverse mixture of old fashioned cultivars in the spring. Certainly the size of the clump indicates it has been there for a number of years, perhaps decades.

Last photo taken November 2020

I had to wait until September 2020 for my next unusual Arum, when this clump was well advanced at Ouzlewell Green (VC63). Clearly it has a relationship to the marked form of Italian Lords-and-Ladies, but the leaf shape is not typical, nor is the yellow-tinged venation. I'm going to keep an eye on this, and again try to see in flower, but at present I think it can only be a hybrid will Lords-and-Ladies.

Asian Dogwood (Cornus koenigii)

Its been just over 10 years now since Peter Sell first brought attention to the fact that that Dogwood (Cornus sanguinea), as understood by British botanists, included two non-native taxa i.e. Southern Dogwood (Cornus australis or sanguinea subsp. australis depending on preference) and Asian Dogwood (Cornus koenigii). Both of which were subsequently picked up from Stace 3 onwards.

Southern Dogwood is very widely planted, indeed many if not most 'native' plantings will be this and on this basis I think dogwood should be avoided in native planting mixes. Clearly growers are making no effort to distinguish native from non-native. As well as planted occurrences, it is also rapidly and aggressively spreading by seed from plantings. For example, it is increasingly being found in semi-natural habitats in Eastern England and West Yorkshire. In my opinion, it is still under-recorded in lowland England, and until more recorders split them (which is quite easy, only requiring a check of the hairs on the underside of the leaf) we won't truly understand how far it has established. Once known it can usually be told at a glance, although the hairs should always be checked.

In comparison, Asian Dogwood is much less commonly seen and of more patchy occurrence. I usually only see it planted into the wild and it seems less inclined to self-sow. So it was interesting to find a bush locally that is clearly of bird sown origin (there are mass-plantings within a few 100m as the berry-eating bird flies).

Asian Dogwood also has a very distinct jizz and can usually be told at a glance. As with Southern Dogwood it can form a large robust bush, but is generally less densely branched and in foliage, and the leaves have hairs like Dogwood. The leaves are typically large (much larger than Dogwood except where this is shade grown, and usually but not reliably larger than Southern Dogwood), clearly longer than wide (some forms of Southern Dogwood can have quite a rounded leaf outline in comparison), and have a markedly acute apex. The petioles are also very long relative to the other two species.

Atlantic Ivy - Overlooked as a Garden Escape?

Atlantic Ivy (Hedera hibernica) is the dominant ivy along the western fringes of Britain, while further east and inland it is generally considered to be replaced by Common Ivy (Hedera helix).  The very robust cultivar 'Hibernica' (also known as 'Irish Ivy') being the exception to this, having been widely planted historically and subsequently has spread widely in suburban areas, railway banks and woodland. Despite this it still seems to be under-recorded. In part this is because in some counties it isn't recorded to cultivar level, instead being lumped under Atlantic Ivy. However, there do seem to be some genuine large gaps that are inconsistent with its ubiquity elsewhere. The BSBI database still lists it and maps it under Common Ivy, which also may confuse matters.

Images of Hedera hibernica 'Hibernica', Swillington Park (VC64)

But this is not the only form grown in gardens, and some cultivars are likely to have been grown for as long as 'Hibernica' and therefore are equally likely to have escaped. I was reminded of this recently, when walking through the woodland on the edge of Oulton Park (VC63). My eye was drawn to what at first glance was a carpet of ivy mixed with abundant tree seedlings, but closer inspection showed these 'seedlings' to be part of a very peculiar and heterophyllous ivy. A few young shoots were gathered to look at under the microscope later, and when I did I found the underside of the youngest leaves (the only reliable place to look, and ignoring the leaf margin and major veins) to have a cover of hairs (trichomes) flat to the leaf surface. So, it was a form of Atlantic Ivy, an identification kindly confirmed later by Hugh McAllister, author of the excellent recent monograph on the genus. Hugh also suggested that it looked like the cultivar 'Gavotte', which in itself is interesting as this cultivar is currently considered to be a form of Common Ivy and therefore would need to be reassigned to Atlantic Ivy.

Hedera hibernica cf. 'Gavotte'

This is the third type of Atlantic Ivy I have found in the woodlands around Oulton Park. 'Hibernica' is of course common throughout, but there is another large leaved form which seems to the old cultivar 'Lobatomajor' (and it may sit within a group of cultivars that comprise the Hibernica Group, as the distinguishing distinctively lobed large leaves only start to appear once it starts to climb).

Hedera hibernica 'Lobatomajor'

So inspired by 'Gavotte', and it being a good autumn project now that most plants have gone over for the year, I visited several woodlands in urban fringe locations this weekend to see if I could find more Atlantic Ivy. Something that turned out to be relatively easy, the trick being to focus on those plants with the largest juvenile foliage and/or leaves redolent of 'Hibernica' in shape. None of these plants was as distinctive as the above forms, and instead resemble more typical wild type Atlantic Ivy. But once you get your eye in they do have a distinctive jizz, and the hairs later confirmed these field identifications. It was by no means dominant within the woodlands concerned, but where it has colonised it generally forms dense stands. I'm recording all these finds as neophytes, as I am assuming that they have a garden or other introduced origin. I suspect focussed searching will find them to be relatively frequent in other suburban and urban edge locations.

Hedera hibernica in Hollinhurst Wood, Allerton Bywater (VC64)

Hedera hibernica in Peasecroft Wood, Great Preston (VC64)

Hedera hibernica near Astley Lane, Swillington to Great Preston (VC64)

Crataegus x rubrinervis

I popped over to Skelton Lake (VC64) today to check up on the bush of Crataegus x rubrinervis (Common Hawthorn C. monogyna x Five-seeded Hawthorn C. pentagyna) I first found in 2018. There are a couple of bushes of Five-seeded Hawthorn a few hundred metres away, and this bush looks like it has arisen in situ.

It has the foliage, large succulent fruit (at their largest they are blackcurrant sized) and suberect sepals (recurving at the tips) of Five-seeded Hawthorn, but with fruit dark red to red-purple rather than purple-black and seeming to ripen later as well. The flesh is reddish coloured, and in this case most of the fruits checked had two pyrenes, but a few had three.

Giant Spotted Medick

I first noticed a giant form of Spotted Medick (Medicago arabica) in St Aidan's Nature Park (VC64) a few years back, where it is widespread, early into growth and achieving a high biomass early in the season, and it can form huge stands to the complete exclusion of pasture grasses. It flowers and fruits early and then dies back for the summer, before having a second flush in the autumn. Annoyingly though I have never been able to put a name to it, despite it having all the characteristics of a useful fodder variety. 

This year I have noticed it starting to spread out of St Aidan's, and have also found it widespread around the stables and horse paddocks at Royds Green (VC63). Clearly, someone is growing it and distributing it in wildflower seed mixtures and for agricultural use. 

Motivated to try again for a name, I've trawled Google and persevered against initial results indicating that this species is rarely cultivated and has no known cultivars. Eventually I stumbled on an old agricultural publication from 1951 (the thrillingly titled Harvesting and Cleaning Grass and Legume Seed in the Western Gulf Region). Finally someone acknowledges that three cultivars were developed in the United States (clearly so long ago that no one remembers their names) and one is called 'Early Giant'.  Could this be it? Well, details are thin but it was considered notable for its early growth and seed production, and it must be called 'Giant' for a reason. So that sounds promising and it will certainly do as a name for now. If anyone knows different please let me know.

Bottom Boat and Back

I made the most of the good weather on Tuesday to walkover over to Bottom Boat (VC63). Its not a route I do often, as it requires a bit of a slog up and over the ridge that separates the Aire Valley from the Calder Valley, but it does offer potential for interesting casuals and escapes and usually provides something of interest.

The day started well before I had even left Oulton with some particularly robust Cockspur (Echinochloa crusgalli) on an arable margin. This seems to have sprung from nowhere given I walk pass this field regularly.

Reaching my target destination I stumbled on a patch of derelict hardstanding with a variety of interesting garden throwouts. This is where I met 'Angelina' (see previous post). Other highlights included:

The golden form of Wilson's Honeysuckle (Lonicera nitida 'Baggesen's Gold').

Pink-sorrel (Oxalis articulata), in association with Stinking Hellebore (Helleborus foetidus) and surprisingly, as I did not know that it can throw up leaves in autumn, Garden Grape-hyacinth (Muscari armeniacum).

Stinking Tutsan (Hypericum hircinum).

Slightly further on, this attractive bi-coloured cultivar of Broad-leaved Everlasting-pea (Lathyrus latifolius 'Blushing Bride') was still going strong.

While an arable margin nearby had the winged form of Black-bindweed (Fallopia convolvulus var. subalatus). Supposedly less common than the nominate form, but that is not my experience.

Working my way down towards the River Calder I moved into abandoned former colliery land. Not the richest of habitats, it needs a few more decades yet, but still with interest and its great that no one has tried to 'restore' it. 

By the farm track on route was a young and apparently self-established tree of Cherry Crab (Malus x robusta), a variable group that perhaps includes plants of other origin. One of the characteristics of this species is that the individual apples are variable in terms of whether or not they retain their sepals. I think it likely that the fruit will colour further, they were in shade so a little behind.

Heather (Calluna vulgaris) is already starting to move in amongst the secondary birch woodland, a species that is very uncommon in the lowlands of Leeds and Wakefield.

But keeping with the theme of unusual non-natives there is also a thicket of sapling Broad-leaved Cockspurthorn (Crataegus persimilis 'Prunifolia'). No idea how that arrived, but it does not look planted. It proved the first of several interesting (at least to me) hawthorns.

Further on, the landscape architects had been in at some point in the last 30 years 'restoring' the landscape and creating 'native woodland'. Of course its nothing of the sort, rank MG1 grassland and the usual mix of false natives and lookalikes. Among these was a tree currently going by the name of Miyabe's Maple (Acer miyabei). The true species is of Japanese origin and, like Alan Leslie notes in Flora of Cambridgeshire, I think our plants are probably something else. The question is what? Potentially it is an unnamed alien form of Field Maple (Acer campestre), but possibly as with many planted 'native' hawthorns, dogwoods, Viburnums and hazels it could be of hybrid origin. Its a striking tree though, with large leaves, long petioles and large keys (glabrous in this case but they can be hairy). The second photo below contrasts it with typical field maple (var. campestre).

There was also Coralberry (Symphoricarpos orbiculatus) and  the hybrid hawthorn Crataegus x subsphaerica. The latter in this case had foliage closer to Common Hawthorn (Crataegus monogyna) but with clear hybrid vigour, but those elongate erect sepals give the game away.

One final hawthorn brightened the walk home. Check out the haws on this Common Hawthorn, c. 13mm long by nearly that wide. Living up to its name of var. splendens. These large fruited bushes occur here and there amongst more typical plants. I'm not quite sure what to make of them (valid variety or just chance?), but they make a stunning sight in the autumn sunshine. The bottom photograph compares it with more typically sized haws from a neighbouring bush.