welcome

Welcome to the Scottish Invasives blog. Invasive non-native species (or INNS) are plants and animals that have been introduced to areas outside their natural range. INNS are currently recognised as one of the greatest threats to biodiversity. The Scottish Invasives blog is intended as an informal forum for those interested in invasive species control. If you wish to contribute, please get in contact. You can click on any of the images to see them at higher resolution.

Friday 20 August 2010

The BBC visit Glenurquhart


The BBC Landward team visited Glenurquhart earlier this week. A useful opportunity to highlight the importance of INNPS.

Is Rosebay Willowherb native or non-native?


A tricky one... The answer is that Rosebay Willowherb Chamerion angustifolium appears to be both native and introduced.

It was a rare upland species in the British Isles until the 19th century, when it dramatically changed its behaviour. Perhaps with the introduction of genes from elsewhere in its range (N. America or Scandinavia, perhaps), it became a vigorous pioneer of disturbed habitats.

It has now expanded its range to most of mainland Britain and Ireland, and is a familiar sight on railway embankments, roadside verges, waste land and clearfell sites. It is a great favourite of bees.

Thursday 19 August 2010

This field of Rosebay willowherb or ‘fireweed’ provides a spectacular scene but also shows how invasive this plant is. I heard from a local man that this field was in use as agricultural land up to only two years ago so this fireweed has really taken hold and spread rapidly in a relatively short period of time. Does anyone have any examples of sites where this invasive is being controlled?

Himalayan balsam Christmas trees?!?...





These Himalayan balsam plants were in an area of felled woodland next to the river Sgitheach, their branching pattern and large size share similarities with the shape of a Christmas tree! Most balsam plants growing in dense clumps tend to be tall and straight with the flowering structures located at the top. I believe this branching pattern may be caused when the plants get snapped off whilst growing but the root and bottom node remain allowing the plant to regenerate and regrow. These few larger branched plants were out in the open with plenty of space which may also benefit this growth structure. Any other suggestions???

Wednesday 18 August 2010

Cutting balsam

Unlike most invasive plants, Himalayan balsam can be effectively controlled without using chemicals. Scattered plants can be uprooted, while dense stands can be cut using a Martindale weed slasher.

Skunk cabbage control



This May we decided to experimentally dig out Skunk Cabbage from a burn here on the estate. There were a large number of plants ranging from tiny seedlings to full grown plants in the water on the bank, in the woods. We first assessed the plants structure decide what was the best approach.


We found that it has a structure a little like a leek with leaves wrapping around each other down to base plate with lateral roots from that. We decided to take the approach of pulling or digging out the base plate to see if that would destroy it's ability to regenerate. On a large plant the base plate can be around 30-40cm deep, on a seedling it is almost at ground level, it varies. We found new leaf buds inside the leaves at the base. Also that when we tried to pull the plant it would routinely separate right above where this bud was growing, presumably to protect the plant from spates.
We dug out all the plants we found, we also tried to pulverise the base plate on really large plants. The best tool is a small spade to get into tight spaces to dig. We think a smallish crow bar might be useful to bash the plate into oblivion, not sure. We do know it's time consuming but the NNSS website says it's not suitable for chemical control (in wet woodlands)
We visited the worst sites a month and a half later and found seedlings we missed, one regenerated plant where we couldn't get to the root but no signs of other plants coming back at all. We think that to get the base plate out, leaving the lateral roots is an effective control but we won't know for sure until next spring. Does this tally with the experience of others?

Sunday 15 August 2010

Spiraea


Another widespread garden escape which seems to be spreading: Spiraea or Bridewort. Flowers may be pink or white. It often forms dense 'hedges' along roadsides. One to watch?


Tuesday 10 August 2010

Sweet Cicely


Sweet Cicely has attractive fern-like foliage.

Sweet Cicely Myrrhis odorata is a native of central Europe, and widely naturalised in Scotland. It thrives best in moist situations, and appears to be spreading in some locations. The seed-heads are distinctive - large and almost black.

Monday 9 August 2010

Touch-me-not

Several Impatiens species occur in UK, but only one is native. Touch-me-not balsam Impatiens noli-tangere (so called because of its exploding seed-pods) is generally considered to be native only in the English Lake District and mid-Wales. If you find this balsam in Scotland, it will have escaped from a garden. Fortunately it is not invasive, unlike its Himalayan cousin.

Saturday 7 August 2010

Buddleia

The 'butterfly bush' Buddleja davidii is a shrub native to the mountains of China. It is widely planted for its showy sweet-smelling flowers.
Buddleia provides conservationists with a bit of quandary. It is very attractive to insects, especially butterflies, but has become invasive in parts of North America and Europe. It doesn't appear to be problematic in Scotland, though it is becoming more frequent in milder areas of UK, such as South-West England and Wales.

Tuesday 3 August 2010

Introducing Rhododendron ponticum ...


Rhododendrons are a favourite of many gardens but this one has got out of control. Introduced to the UK around 1763, Rhododendron ponticum was favoured as a hardy flowering plant, popular on Victorian estates to provide colour and game bird cover. Since then, it and it's hydrids (often referred to collectively as wild rhododendrons or 'rhoddies') have 'naturalised' and spread across hillsides and woodlands throughout the UK, posing a very significant threat to native mosses, lichens, wildflowers and woodland plants and the wildlife they support.

The Highland Rhododendron Project aims to support land managers and communities tackling this spread in and around designated sites in Highland and promote and disseminate best practice in its removal