The Red Horsechestnut, Aesculus x carnea, including 'Briottii'

The "Red" Horse Chestnut is a (tetraploid?) cross between the shrubby Red Buckeye or Firecracker, Aesculus pavia of the mid-west USA and the Common Horse Chestnut, Aesculus hippocastanum, of South Eastern Europe. The hybrid appears to have been around since early Victorian times, possibly arising in Germany by 1820.


It is a generally "desired" tree although Alan Mitchell, writing in the 1970s,  disparages it greatly, as dark and uninteresting, but thankfully short-lived! Does not get much Horse Chestnut Leaf Miner, which is a relief. A bit less troubled by diseases than A. hippocastanum, but does seem to have physiological bark breakdown problems and to get bleeding canker a lot, limiting its life span.

There are three red horse chestnut trees at the front of Hadlow college, one by the road and two by the river. They vary slightly in the hue or "redness" of the flowers, but whether one or more is actually "Briotii" is a guess well above my pay grade - but I think NOT. 

Could this one be 'Briotii'?

According to the RHS Dictionary, the tree is "low-domed" but this must be relative. The bark is said to turn from dull green tinged pink, becoming red-brown and rough with distinct lenticels. The branches are said to be twisted and spreading, with drooping tips.

 The buds are terminal, often in pairs. They are up to 2.5 cm long, ovoid and slightly resinous.

There are 5 - 7 leaflets per leaf, each sub-sessile, obovate up to 25 cm long, actually broader than in A. hippocastanum (?), wrinkled, dark green above, lighter green beneath, double crenate, the leaf with a petiole of maybe 23 cm. The leaves should often be recurved and twisted. Midrib is red at its origin?

The flowers form panicles 20 x 10 cm. The flower corolla is up to 1 cm in length, the petals rose-pink, their centres blotched yellow initially, then the centre turning cerise as the flower is pollinated. The petal margins should be glandular - which I have never noticed before! Stamens protrude slightly, but nothing like as far as in A. hippocastanum.

The spiny fruit is spherical and up to 4 cm diameter. There are 1 - 3 small seeds or "conkers".

'Aureo-marginata' Leaves edged with yellow.

'Briotii', perhaps called the Ruby Horse Chestnut, has a larger inflorescence, with much darker red petals, with a glabrous pistil. The fruit is only laxly spined. Notably dark green foliage. Red "midrib" - (must be petiole)? The cultivar was named in 1858 to honor Pierre Louis Briot (1804-1888), the chief horticulturist of the State gardens at Trianon-Versailles near Paris,

'Foliis Marginatis'

A variegated form with a dark green border to the leaf, then an irregular band of yellow, the centre being pale green

'Fort McNair' (named from where it was selected) has dark pink flowers with yellow throats and resists leaf scorch and leaf blotch. It has a more 'pavia' type leaf.

'O'Neil', or 'O'Neill Red' produces larger (10–12 inch) panicles with brighter red flowers. Introduced by Monrovia nursery in about 1979 (Jacobson,1996).  Monrovia spells the cultivar name as O'Neill; many variations of this name are found in nursery catalogs and horticultural publications.

'Plantierensis' is a back-cross to A. hippocastanum. There are usually 7 sessile leaflets, uneven with ribbed blades. The inflorescence is very like A. hippocastanum but a delicate pale pink. The fruit is prickly but undeveloped, as it is triploid, so you don't get conkers. The origin of this cultivar is the nursery of Simon-Louis Frères, Metz, France, 1894.

'Theo Jansen'.

See list at Pavia Nurseries, Holland, a leading supplier of Aesculus plants in western Europe.

There are some very nice Aesculus at the Almshouses, Faversham, including this very pretty Aesculus x carnea.

The Ohio Buckeye, Aesculus glabra

Fascinated by this tree just by the Guild Hall in Faversham, the County Champion for girth and height.

Description: 10 - 30 m. tree, bole to 40 cm diameter. Bark light to dark grey-brown, becoming much lighter, fissured. Red-brown branchlets becoming light-grey. Buds conical, acute. Leaflets 5 - 7, 6 - 16 cm long, 2 - 6 cm wide, obovate to elliptic, long acuminate, acute at base, glabrous to tomentose beneath, dark green, toothed towards apex, petioles 5 - 15 cm. The leaves are said to smell "off" when crushed, hence the foetid buckeye. Good autumn colour.

Peduncles and pedicels are hairy. Flowers in 10 - 15 cm, glabrous to densely hairy, calyx cup shaped to 1 cm, lobes obtuse. 4 pale yellow green fringed petals form the corolla, up to 2 cm long. Upper one with  a hairy claw to half its length, lateral ones have a shorter hairy claw and are broader and ovate. 7 long stamens exserted to 2.5 cm, with orange anthers. Light brown ovoid fruit up to 5 cm diameter, more or less prickly, contain 1 - 3 dark brown conkers 2 - 4 cm diameter.

https://www.minnesotawildflowers.info/tree/ohio-buckeye

The flowers are probably quite pretty in close-up:

The Buckeye is a very nice tree and the state tree of Ohio, the Buckeye State. People used to carry the nuts in their pockets against rheumatism. All parts of the tree are potentially toxic however. People of the First Nations used to extract tannic acids from the nuts to tan leather and are also said to have used powdered nuts in water to stun the fish. Turned out quite symbolic in the election of President William Henry Harrison, who was from Ohio.

Camer Park

There are a nice selection of trees in Camer Park, planted at various times, I presume much later than the extension of the house in 1716.   In fact some of the trees were not introduced until the 1830s at the earliest.

A previous post described in detail the wonderful three trees which are located in the centre of the garden. Close by is a single Japanese Pagoda or Scholar Tree, Sophora (Styphnolobium) japonica, which is showing a lovely autumn flowering this year (the usual period for this tree) - I wonder if the unusual summer has had anything to do with this showiness, or whether it is normal. The creamy white flowers are produced in really generous panicles, nicely exotic. I don't think this is the dramatic weeping form, probably just the standard species, which was introduced to the UK in 1753.

It is actually a Chinese tree but has traditionally been widely cultivated in China, Korea and particularly Japan.

It is a good landscape tree, but tends to shed year-round, a bit of a nuisance. Its durable wood is used in boat construction and building, and most parts (except the pod) have good uses in Chinese Medicine.

The fruit is a leguminous and toxic tomentum, splitting into one-seeded parts.

Zelkova serrata at Camer Park, Meopham.

Very pleased to identify a Zelkova at last, although I do wonder whether I have seen leaves from this tree before, but failed to give it any name at all in the past!

Once I spotted the correct genus in the Collins guide, after spending a long time determined to fit these leaves into the genus Nothofagus, I was absolutely delighted to head almost straight away towards Zelkova serrata. Several pointers - the leaves hanging DOWN, which I had thought might be due to the drought or time of year, but is actually a characteristic of the species, and the number of vein pairs - 12 on the leaves I looked at fitting in with the stated 9 - 13.

The upper surface of the leaf is "micro-rough", even finer than an Elm might be. The underside is contrastingly glabrous. The toothing on the leaves didn't immediately seem to fit the book descriptions exactly, but seems to fit a range of the images on the internet very closely. The leaf size is given as 6 - 12 cm, and I thought these were at or just over the top of this range.

The tree is said to be quite beautiful when the leaves turn. I look forward to the stated orange colours this autumn!

Zelkova serrata, the Keaki (or Keyaki), is from Japan, China and Korea. It was often grown in Japan for timber, ornament and bonsai. A spreading habit is often referred to, very obvious in these three trees. The spreading habit in these trees might help support the theory that these trees might be old enough to have been grown from early batches of Japanese seed brought to the UK in the early 1860s.

The bark is grey, smooth and very Beech-like, to my eyes indeed. There is no sign as yet of any bark flaking off to reveal orange patches beneath in this tree - except the split on the right. There were plenty of flakes with underlying dark orange on the right-hand tree which was examined the following day, photo not yet available.

The twigs are slender with small, dark conical buds held in a zigzag pattern on the twigs, each bud pointing outward at a fairly characteristic 45 degrees. The pattern, in hindsight, is really very elm-like, as in the photo taken from the bench underneath the tree's canopy.

The species is said to be pollution-resistant (not sure why this isn't a moveable feast, as pollutants change over time).

The yellow-green flowers occur in tight groups, perhaps high in the canopy and the fruits are small, pea-green drupes. An American source has the fruit as a small triangular drupe, pea green turning brown, sub-sessile, 2.5 cm long and 2.5-3.5 mm in diameter with the surface covered by an
irregular network of low ridges. 

The currently recognised county champion for girth and height is 13 m high with a girth measured at 240 cm at 1.1 m, in Cherry Ingram's old garden at the Grange, Biddenden. The notes on the Tree Register suggest that this might have been grown from Japanese seed. The first tree I measured at Camer Park, the first of three, has a greater girth than that, 240 cm, measured at 75 cm height, and the second, with a much more muscly trunk, measured at 261 cm, measured at height.

The timber is very valuable as it is fine-grained and rot-resistant. It is much used in high quality furniture, construction and ship-building. It is also traditionally used in the making of the Japanese drums called Daiko, as seen in this video here: https://www.youtube.com/watch?v=C7HL5wYqAbU. The Wikipedia page on Daiko is also exceptionally good.

The Zelkovas are in the Elm family and used to be spread across the north Temperate zone. Zelkovas differ from Elms in that the seeds lack a wing, and the bases of the leaves are much more symmetrical. A Zelkova that looks a little like Z. serrata is in the North American fossil record from the Eocene. However, Zelkovas are thought to have died out in North America in the Tertiary period.

Acer cappadocicum, the Cappadocian Maple

Acer cappadocicum is a fairly large tree from Asia Minor - Turkey, Iran and the Caucasus across to China. It SHOULD be fairly easily recognised as its got quite distinctive un-toothed triangular palmately-arranged lobes to its leaves. It is said to have obvious milky sap in its leaves, and I saw some evidence of this.

More says it always throws up root suckers - but I didn't see any root suckers at Cobtree Manor Park, where I came across this strong contender for the ID in mid-August 2018. The leaves look the right shape, but do seem quite large (up to 15 cm) in relation to the dimensions given in this book, 5-10 cm. However Wikipedia supports up to 15 cm.

The tree is quite a late introduction to Western Europe, said to be as late as 1838. It is thought to be commonly planted in large parks and gardens - Leeds Castle for example has a bit of a collection of Acer cappadocicum.

The day after I first saw this tree at Cobham Manor Park, I saw a second tree just by the car park at Camer Park near Meopham! The tree is quite a light green overall, covered with multitudes of yellowish good-sized double samaras in the middle of August.

And, when I checked, there were indeed quite a few root suckers.

Acer tataricum ssp ginnala, or simply Acer ginnala

I found a well-established plant that I think must be this, to the north of the Japanese Pond in Broadview Gardens.

The leaves are quite a characteristic shape:

Acer pensylvanicum - Moosewood - the coloured bark form labelled 'Erythrocladum'