Along the burn are a couple of notable garden escapees one a big plus the other a big minus(not from our garden - at least not in the last 3 years that is) - the Giant Hogweed and the Monkey Flower. Let's start with the Monkey Flower - something me and Jiurie are trying to encourage. This could be Mimulus guttatus (Monkey Flower) which I've just read on Wikipedia is one of the main species used for genetic research - over 1000 scientific papers on just the genetics of this one plant. I won''t be reading any -I hardly ever did read read scientific papers when I was a student (which is why I was a first-class science student at any level) - read the abstract and then photocopy the paper just in case (just in case of what I don't know as I never ended up reading the papers I think I expected my brain to assimilate the information by osmosis - just in case of... nope still can't come up with a valid rationale). Ther's a couple of asp[ects of the biology I might investigate though - they are supposed to be edible and they concentrate salt so can be used as a salt substitute/source ... I might give it a graze next time I'm down by the burn. 
The Mimulus is right at the edge of the burn which is a classic place to find garden escapees - the seeds being brought down the stream and depositied when the winter and spring melt subsides. The other garden escappe is strange as it appears to be moving up stream - that is we saw it last year around the burn beyond the dual carriageway bridge 50 yds or so downstream from the end of our garden. This year there 3 or 4 have popped up along the side of our burn - the buggers. We are talking about the giant hogweed here - a noxious plant that it is illegal to plant it or to cause it to grow on your land. However we don't have to remove it - just make sure that it doesn't spread to anyone else's land. Seeing as our neighbour has it already and may have allowed it to spread onto our land then we are in the clear - I wonder if we could sue them?
"Legal implications of invasive weeds
If you have Japanese knotweed, giant hogweed or Himalayan balsam on land that you own or occupy you:
do not need to notify anyone are not obliged to remove or treat these plants on your own land
must not allow Japanese knotweed or giant hogweed to spread onto adjacent land; the owner of that land could take legal action against
you must not plant or encourage the spread of japanese knotweed or giant hogweed; this can include moving contaminated soil from one place to another, or incorrectly handling and transporting contaminated material and plant cuttings." http://en.wikipedia.org/wiki/Giant_Hogweed
http://www.netregs.gov.uk/netregs/63107.aspx
I can see why the Victorians introduced it - it is big is good-looking (like me... joking m- you could add that it is a poisonous vegetable like me so we won't push that comparison any further). The one in the corner of the Ram field over the burn is at least three metre tall - well taller than me. 
It is a very handsome plant butthe poisonous hairs and the very poisoud sap can leave your skin photosensitivce or blid you if it gets in your eyes. I guess I need to go hack it down or spray with glyphosphate to protect the wife agrandkids and dogs - pity.
Here is the leaflet from the UK Govt Environmental Agency - I'm just helping to distribute this as a public service (if I paid any income tax then I would help pay their wages so maybe they should be paying me - although I do pay my 17.5% VAT and a load of tax on Petrol and everything else I buy.)
http://www.environment-agency.gov.uk/static/documents/Leisure/giant_hogweed__899765.doc
Giant Hogweed
Giant hogweed (Heracleum mantegazzianum) was introduced to Britain in 1893 as an ornamental plant. It escaped from gardens and now colonises many areas of wasteland and riverbanks. It forms dense colonies that suppress the growth of native plants and grasses, leaving the banks bare of vegetation in winter and increasing the risk of erosion and recolonisation from seeds washed downstream.
Legislation: The Wildlife and Countryside Act 1981 provides the primary controls on the release of non-native species into the wild in Great Britain. It is an offence under section 14(2) of the Act to ?plant or otherwise cause to grow in the wild? any plant listed in Schedule 9, Part II. This includes Giant hogweed.
HEALTH HAZARD
The stems, edges and undersides of the leaves bear small hairs containing poisonous sap, and the slightest touch causes painful blistering and severe skin irritation. Unshaded habitats with high soil nitrate levels tend to produce greater quantities of toxins in the plant. Contact with cut material in sunlight produces a skin reaction in almost all cases. Blistering symptoms occur 24- 48 hours after exposure, and dense pigmentation is visible after 3 ? 5 days. This may persist for 6 years or more. Protective clothing must be worn.
Facts and figures
Native range: Caucasus mountains.
Lifecycle: It is a perennial plant that takes up to 4 years to mature and flower, after which it dies.
Stem: Green with dark-red or purple blotches.
Hollow
Up to 100mm across
Up to 5m tall.
Leaves: Dark green, in a rosette
Jagged appearance and spiky at the ends
Lower leaves up to 1.5m long.
Flowers: White
Several hundred in large umbrella-like flower heads up to 500mm
Across.
June ? July.
New plants: Each flowerhead produces up to 50,000 seeds (approx. 10mm x
7mm) that are easily dispersed by water, so the plant disperses
rapidly along watercourses. Seeds may remain viable for up to
15 years.
Control: Aim ? to kill the plant or prevent flowering.
Chemical control is most effective. Spraying can start as soon as the plant is about 1m high, usually in March and continue throughout the summer. More than one application is often necessary and follow-up spraying will be required to kill seedlings in subsequent years.
Non-chemical control Cutting down stems with a sharp scythe before flowering will help control this plant. Flail mowing is possible but with extreme caution due to the risk of being sprayed with sap. Protective clothing should be worn.
The crown may be dug out just below ground to prevent regrowth this provides good control.
Grazing by cows and sheep will suppress growth but will not eradicate it.
It is essential to establish vegetation quickly after control measures have been applied, as dense grass sward tends to discourage seed germination.
Disposal: Should be taken to a landfill site or by piling on site and composting.
Useful links:
http://www.environment-agency.gov.uk/netregs/processes/367839/?lang=_e&textonly=on
