The most spectacular colonisation however is along the M25. 1 have not surveyed the entire
motorway, but in the northwest sector, patches start at the Ml 1 junction on banks often some
distance from the road, and then around the various j unctions to Heathrow it grows in dense
beds high up on the soil behind vertical concrete retaining walls. Along the A12 and A120 it
tends to get flailed before it can flower, but along the M25 it flowers in profusion. The tall
inflorescences looking at 50mph like a rather delicate off-white Michaelmas daisy with very
small flowers. They oscillate violently in the draft from large container lorries and it is easy
to imagine how the seeds get wafted along the motorway and up onto these high banks.
Dittander is inexplicably rare along the southeast Essex coast and the Thames valley. Recently
however it has begun to appeal' along the streets and on waste ground in the east end of
London. Maybe it's our recent spate of hot summers combined with an increase in salinity
that is encouraging it.
Another verge plant that has been on the move in from the coast for some 20yrs or so is
Alexanders Smyrnium olusatrum. Producing its leaves in late autumn and flourishing
throughout a mild winter it stashes away plenty of goodies underground, and is easily able to
withstand flailing later on. Patches of it are appearing along roadside verges all across the
county. Large colonies now occur on Wanstead Flats, in Woodford, at North Weald, and
along the Al2 west of Colchester down as far as Brentwood. Often appearing some distance
from the splash zone, however, it would appear to be its ability to withstand flailing that is
helping it along its way, rather then salting, possibly encouraged by our milder winters.
Finally, yet another salt tolerant maritime plant is on the move. Sea Fern-grass Catapodium
marinum, formerly a rare plant of upper saltings and sea cliffs in Essex, has spread as a
narrow but dense band along the edge of the north verge of the Colchester road west from
Weeley. It has apparently been noted spreading along salted verges elsewhere in Britain
since the mid 1980s. One year it smothered a newly gravelled car park at Loughton College,
suggesting that the gravel used carried a good inoculum of seed. The most unexpected site
for C. marinum, so far, is a single plant on the Vc21/Vc18 border, in the middle of a cast iron
bridge over the R. Lee at Springfield Marina, just north of Walthamstow marshes. Anyone
finding new sites for these plants along our salted verges is requested to send me (or Terri
Tarpey as appropriate) the records.
Four Water Poplars for the price of one
Ken Adams 63 Wroths Path, Baldwins Hill, Loughton. IG10 1SH. 020 8508 7863.
The number of veteran 'Native' Black (Water) Poplars occurring in Essex (Vc18 and Vc19)
continues to rise as we discover more lost trees, (220 at 73 sites, 55 females) but we arc also
losing an alarming number of trees each year. These loses are due to three main factors. The
tendency in recent years to have excessive summer droughts - Water Poplars need a lot of
water. We have also been experiencing excessive gales in recent years and trees have either
Essex Field Club Newsletter No. 42, September 2003 21