Sunday, 22 July 2012

Invasive Species

During the summer months our rangers and volunteers spend a great deal of their time controlling invasive plant species.  Invasive plants are robust and fast growing and if not controlled spread rapidly shading out more delicate flowering species.  Many are non-native having been brought here as colourful additions to parks and gardens.  Examples include rhododendron, japanese knotweed and himalayan balsam.

Japanese knotweed

Japanese knotweed grows typically 2m to 3m tall at a rate of up to 10cm a day and is difficult to control as tiny fragments of root can grow into living plants.  The stems are rather like bamboo shoots, the leaves large and and spikes of tiny white flowers are produced in late summer.  It is best treated with a herbicide although even then repeat applications may be required.

Volunteer Mathew pulling himalayan balsam

Himalayan balsam is a member of the bizzie lizzie family and grows rapidly to a height of up to 2m or even more in favourable sites.  The stems are very succulent, the large leaves spear-shaped and pinkish flowers are shaped like an old fashioned policeman's helmet giving rise to its alternative common name.  A shallow root system makes this an easy plant to control simply by hand pulling.


Rhododendron is an evergreen shrub with dark green leaves and attractive large purplish blooms.  We contol this by cutting back stems with saws and loppers and treating the stumps with an herbicide to prevent re-growth.


The bees are back in town!

The observation beehive in the corner of the Walled Garden
The beekeepers of the Newcastle Beekeepers Association brought a colony of honey bees back to our observation hive this weekend.  The bees have been overwintering in another hive at Gibside's Cut Thorn Farm.  Usually they would have been back in the observation hive much earlier in the summer, but because of the unseasonable weather, it was safer to leave them at the farm.  The beekeepers were waiting until the weather was fine for a few days running, so that the bees had time to orientate themselves in our Walled Garden.
Open the door of the hive and watch the bees at work
There are more conventional hives in the corner of the garden, behind the pond, but the observation hive has doors to open on each side, so you can watch the bees working inside the hive through a perspex window. 

Next time you're at Gibside have a look in the hive and see if you can spot the queen bee.

Up close with honey bees
There is a chimney up the side of the hive which has two pipes running through it.   At the back of the hive, at about two metres high, the pipes emerge and this is how the bees get in and out of the hive.  It is designed so that the bees go in and out above human head height, so they don't come into contact with people. 
The entry and exit holes for the hive
Once they come out of the pipe, they can make their way to the nearest flowers in the garden.  The herbaceous border which runs along the wall from the greenhouses was planted with bees and butterflies in mind, and it contains lots of nectar-rich flowers.

Saturday, 21 July 2012

Pumping our troubles away!

Since the flash-flooding of two weeks ago our team has been working flat out to try and get all our paths repaired and open for visitors.  We have also had many culverts to unblock after the huge amount of rain washed branches and sand down the streams and blocked up the drainage systems.  We managed to get all the paths reopened this week, after repairing some of them more than once when the rain kept coming.

One culvert that gave us trouble was a pipe that takes the Leap Mill Burn under the main drive.  Any visitors to Gibside will have noticed the pool at the side of the drive growing over the last week or so. 

The pool at it's height

 There was water coming through the other end of the pipe, but everytime the water level dropped, an overflow futher upstream would open and more water gushed down.

Overflow water from the near-by town of Burnopfield
We needed to open up the culvert to let the water through before the pressure of the water washed the road away, but to access the culvert, we needed to get rid of the water.  So we hired a huge pump.

This pumped water at 500 gallons per minute.  We thought it would be clear enough for us to get to the culvert entrance in a few hours.  Well, it took 11 hours with the pump running constantly for the level to drop enough for us to see the blockage!  Although there was some water getting out through the culvert pipe, the burn was constantly running and filling up the pool. 

When we could finally get down to digging, we found that the pipe entrance was covered with logs and branches, and the silt had built up behind them.  Some of the logs were huge, and we needed a winch to lift them out.

A few of the muddy logs and branches that we removed form the blockage.
  By 10.30pm we had the culvert running well, and we decided to call it a day.  We all went home shattered and covered in mud to have nightmares of the culvert re-blocking and the pool filling up again.

The entrance to the culvert
 Thanks to the late night of hard work we had cleared enough debris so the culvert kept flowing and the flow helped to clear a lot of the smaller twigs and silt.  You can just see the green metal box at the top left of this photo, which was surrounded with water in the first photo.  The pool of water that collected must have been 12 feet deep.

Since then the sun has come out, and we're hoping it stays that way - we've seen enough rain and mud to last for a while!