Postbag Edition

This week the team is in the GQT potting shed in Sparsholt to tackle listeners' questions as Eric Robson hosts a postbag edition of Gardeners' Question Time, with Matthew Wilson, Christine Walkden and Anne Swithinbank on the panel.

Produced by Robert Abel
A Somethin' Else Production for BBC Radio 4.

This week's questions:

Q. I have two species of Acer Palmatum, or Japanese Maple, both around 8 years old. I transplanted one, the leaves of which have gone a beautiful deep red rather than the usual rust colour. What affects this change?

A. This is almost certainly to do with stress, so you may need to transplant them every year! Pelargoniums react in the same way to stress.

Q. An Echium Pininana seed has taken root in a large stone pot alongside an established Cercis Canadensis. The Cercis Canadensis lost a lot of top growth this winter. Will separating them mean losing them both?

A. Echium Pininana should be fine to be transplanted and bedded out, taking great care with the large taproot. Alternatively, as the Echium is a biennial, it will die after flowering and could be left in the same pot until that happens. However, if the top of the Cercis Candensis does not return after pruning, it may be lost.

Q. Should autumn leaves be removed from flower and shrub borders?

A. Under trees and shrubs where there is capable ground cover, they can be left. Around small or delicate groundcover plants, I will remove them, mulch them down and then return them.

Q. How do I prevent grass growing in my long gravel path?

A. Lifting the gravel and laying a geotextile or terram beneath it will suppress the growth of grass. Alternatively, you could sprinkle seeds and add flowers to the grass. A very light spraying of glyphosate once a year would help. Alternatively a flame gun could be used to deal with weeds.

Q. Due to the wet weather, my garden is overgrown with weeds. Can I leave it for the frost to kill off or do I need to weed it?

A. Between now and Christmas is a good time to weed. Next year it would be advisable to apply mulch and cover any weeds you can't pull up. The frost won't help you!

Q. Last Christmas I bought a red Poinsettia which was very healthy. I planted it out and it is now a large, healthy and green plant. How do I make the red colour come back?!

A. The poinsettia requires short days, so the exclusion of light (14 hours of darkness in every 24) is important for flowering.

Ash Dieback Disease

Ash dieback is a serious disease caused by a fungus called Chalara fraxinea. The disease causes leaf loss and crown dieback in affected trees and can lead to tree death. Chalara Fraxinia is considered to be so serious a threat that the government's COBRA emergencies committee met to discuss it.

The Forestry Commission would like the public to help spot affected ash trees and to report them. The Commission's website has useful photos and a video guide on how to spot the symptoms and how to report suspected cases.

You can find this here:

There is also a smart-phone app that has been developed by the University of East Anglia that shows symptoms and allows suspected cases to be reported. More information on this app can be found at:

Affected trees can be reported using the following contacts:
In England and Wales, on the Chalara helpline: 08459 33 55 77 or email:

In Scotland, to Forestry Commission Scotland: 0131 314 6156 or email:

The Forestry Commission are appealing for everyone to think about bio security - in other words the possibility that fungus could be spread on footwear, clothing, gardening tools, even our pets - and, if out and about in gardens, parklands or countryside, to think about the need to clean anything that might have come in contact with the ground or the trees themselves before venturing out again.

Release date:

Available now

43 minutes

Last on

Sun 11 Nov 2012 14:00

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