Facebook Questions and Answers for the 23rd September 2011

Hello Facebook fans, thanks for your questions this week, here are Carly's replies:

Julie Gallimore

please can u tell me how low i need to cut some roses down and a rose tree, I never cut them back last yr as didnt know how far, i know nothing about gardening but love my roses and do not want to kill them as the rose tree is 11yrs old.

Hi Julie, don't worry; roses are actually very tough and forgiving plants! When you say 'Rose tree' I'm going to assume you mean a 'Rose standard', which is a rose bush on top of a tall bare stem. Roses are normally pruned after they have finished flowering. If your roses have a single flush of flowers during early or mid-summer (old rose varieties and rambling roses) then these should be pruned soon after flowering. If your roses are repeat-flowering they can be pruned after flowering has finished in the autumn. However with our recent severe winters it may be best to wait until February or early March to prune. For more information about pruning different types of roses take a look at our 'How to grow roses' article. There are some pruning pictures there which may help to guide you as well.

If your roses haven't been pruned for many years it's best to carry out some renovation pruning first, which is a bit less severe than the techniques described in our article. Renovation pruning is best carried out in the winter, regardless of which type of rose you have. All you need to do is remove dead, damaged or diseased branches completely. You then shorten all remaining growth down to half its length. When shortening thick old stems, cut them back to strong new shoots. Make the cut just above the new shoots. Once new growth has emerged next summer the old growth can be cut back to the base the next winter. With regards to your Rose tree or Rose standard, treat the growth on top as you would a normal rose (you can identify which type of bush is on top from our 'How to grow roses' article but don't cut into the long bare stem. These types of roses are grafted on to the top of a stem from another rose species, so cutting below the graft would remove the desired rose completely. Treat the graft point (normally visible as a bulge at the top of the bare stem) as if it were the ground level from which the rose is growing. After any pruning it is a good idea to feed and mulch your roses in the spring to help them recover. Hopefully after a little pruning your roses will put on healthy new growth and plenty of flowers! I hope this helps Julie, best of luck with your roses.

Claire Worrell

Help! My mother's garden is being ransacked by foxes. Digging up the roots of her plants and fouling everywhere. Do you have any advice? Thx

Hi Claire, unfortunately it's not easy to deter these animals. They are quite capable of jumping tall fences, particularly if there are objects they can use to propel themselves with, such as bins or trees. There are products available which claim to deter foxes such as ultrasonic alarms, which are loud to fox's ears but inaudible to humans. There are also strong-smelling chemicals available which you can spread in your garden to repel foxes, although they will probably need applying regularly and after heavy rainfall. It is worth considering if anything may be attracting the foxes into your garden. Foxes like to drink from garden ponds, so if you do have one then you could install netting to prevent them accessing the water. They will also be attracted to waste falling from bird feeders and any open compost heaps. Many pest control experts will be able to remove foxes humanely although this could be quite expensive. For more information it is worth having a look at The Fox Project's website

Anne Preston

I have a compost bin provided by the council. It has been in action for about 2 years but so far it has produced no decent looking compost (as seen on TV gardening programmes. The only wildlife in evidence are slugs and wood lice. Where am I going wrong please. PS. I am 73 with arthritis so some jobs are a little difficult.

Hi Anne, composting is a bit of a balancing act - you have to get the right mixture of materials to keep the process going. The most important thing with a compost heap is to incorporate enough air for the bacteria, fungi and insects to do their work. Slugs and woodlice are a good sign as these creatures will help break down the materials for you!

The biggest causes of failure in composting are poor air circulation and incorrect moisture levels. You should aim to have between 25-50% green material in your compost bin, which includes grass clippings, kitchen waste and young weeds; and the remainder brown material, which includes torn up cardboard, woody prunings, paper, straw, wood chips and dead leaves. It's important not to drown your mixture with any one ingredient - particularly grass clippings as these become easily compacted, reducing oxygen levels and preventing organism activity.

Make sure you turn your compost with a garden fork about once a month. This helps to incorporate air, which is crucial to the rotting process. If you find this particular task difficult, perhaps you have a friend or neighbour that could do it for you. You could also try adding a layer of loosely scrunched up newspaper before you add a layer of grass clippings or other green material. Although moisture levels shouldn't be too much of an issue if your bin has a lid you may need to moisten the compost if it becomes dry and fibrous looking. Alternatively if it is very wet and slimy you may need to incorporate more brown woody materials.

It's best if your compost bin is resting on bare earth but if you have had to put it on a hard surface make sure you put in a spadeful of garden soil to help introduce bacteria and fungi. Most garden centres also sell compost 'activators', which help kick-start the rotting process. It is also possible to buy some worms for your compost bin, which may help. I hope this helps shed some light on your composting problem Anne, I hope you get some useable compost soon.

Cathy Johnson

Hi Carly, being a little cheeky as I have 2 questions! Some of my shrubs have got rather large and leggy this year, is it ok to give them a light prune now as I'm a bit concerned they might get damaged if we get bad weather again this winter. Also, I have a dry shady steep bank at the bottom of the garden, plants don't tend to do well there, do you have any suggestions for tough plants that might survive better?

Hi Cathy, it's best to prune deciduous shrubs once they've become dormant and the weather has cooled considerably, normally from late autumn onwards (or as late as you can leave it before we hit bad weather!) It's worth noting that some shrubs will happily flower on new wood and others will need a summer to develop flowering wood for next year, so you may inadvertently end up cutting off some of next year's flowers. However if this saves damaging the shrub over winter it may be worthwhile this year. Evergreen shrubs are best pruned throughout late spring and summer as harsh winter weather can damage the freshly pruned areas (as these shrubs don't go dormant for the winter). There may not be enough time now for the wounds to heal before the onset of frosts so I would leave any evergreen shrubs until next year.

With regards to your dry, steep bank there are a few plants which can cope with these difficult conditions. You could try tough shrubs such as Cotoneaster, Eleagnus, Hypericum, Mahonia, Sarcococca, Osmanthus or Symphoricarpus (Snowberry). Or if your bank is a bit too small for shrubs you could try Alchemilla mollis (Lady's Mantle), Foxgloves, Lunaria annua (Honesty),Bergenia, Dicentra, Dryopteris filix-mas(Male Fern), Epimedium, Geranium nodosum, Geranium phaeum or Liriope muscari. If you're a bit of a bulb fan then Anemone nemorosa, Cyclamen, Colchicum (Autumn Crocus), Snowdrops and Bluebells will all cope well with a dry shady spot. I hope this helps Cathy, good luck!

Alan Carter

Following the earlier query about composting we have a horse chestnut tree in the garden with leaves affected by the leaf miner. Is it OK to add these to the compost or should they be burnt?

Hi Alan, I'm sorry to hear that you've been affected by this pest. Unfortunately the Horse Chestnut leaf miner over-winters as pupae inside the leaves. It is best to destroy the leaves by burning if possible or by submitting them to your local council recycling scheme, as their compost heaps should reach temperatures high enough to kill the pests. Home composts heaps are often too small to reach the temperatures needed to destroy the pupae. I hope this helps Alan.