Peter Gibbs and the GQT team tackle gardening questions in his very own garden in Berkshire. The panellists are Pippa Greenwood, Bunny Guinness and Christine Walkden. In addition, Anne Swithinbank and Bob Flowerdew meet a roses expert at Mottisfont Abbey in Hampshire to get the lowdown on scent and longevity of flowering.

Produced by Howard Shannon.
A Somethin' Else production for BBC Radio 4.

Questions answered in the programme:
Q. In Act 1 of Shakespeare's Henry V, the Bishop of Ely says "The strawberry grows underneath the nettle, and wholesome berries thrive and ripen best, neighbour'd by fruit of baser quality". Has any member of the team tried nettle planting?
A. The quote probably refers to wild strawberries, as they would not have had cultivated strawberries in Shakespearean times. Wild strawberries do not require the sun like cultivated varieties but, on the whole, nettles are not to be recommended for companion planting!

Q. My bare-rooted Malwina strawberries are sprouting new plants from the pointed tip of the berry. Is there something wrong with the plants, or the way I am cultivating them?
A. These could be parthenocarpic fruit (produced without sexual fertilisation), as a result of this year's unusual weather.

Q. Can I continue to use rhubarb leaves as a mulch for keeping the weeds at bay, or might these poison the soil and make it unsuitable for growing vegetables?
A. No. In such minute quantities and diluted by rain, the oxalic acid will not be a problem.

Q. I planted a Virginia creeper at the front of our house and after ten years took it out. I have since found tendrils growing within the cavity wall. Do Virginia creepers regroup within cavities and, if so, what is the best way to get rid of them ?
A. A systemic weed killer should get rid of it, for example Glyphosate. Removing the plant mechanically (without weed killer) can damage the pointing/brickwork.

Q. My newly planted New Dawn roses have come up white instead of pink. Is it true that pink roses are coming up white this year because of all the rain?
A. Yes. Not just pink to white, but other coloured roses coming up paler too. This is probably related to potassium deficiency as a result of nutrients being washed out of the soil by the high rainfall. Lower light levels are also affecting them. Give them time and a good rose food and they should be fine next year.

Q. I have bought some 3in tall hellebore plants. What do I do with them now?
A. Plant them out, give them a good mulch and leave them to get on with it. Keep them moist and try not to move them once you have planted them out.

Q. This year my allotment was affected by potato blight. Is there any way of cleaning the soil and how long will it be before I can plant potatoes in the area again?
A. Blight does go into the soil, unless you thoroughly remove the affected greenery promptly - do not do anything but bin or burn what you cut down. If the blight is in the soil, keeping susceptible plants out of the soil for a three year rotation will clear it.

Q. How do you dead-head pelargoniums? Mine have brown parts on the flower head which I would like to remove without taking off the healthy parts too.
A. Use a pair of pointed hairdressing scissors to get into the flower head and take off the individual flower stalks.

Q. Over the decades, my hedges have steadily grown in width and height, despite annual trimming. When and how should I attack them with a chainsaw? The hedges include Escallonia, beech, Australian holly and hawthorn.
A. Wait until next February/May and take it down to about half. Alternatively, those species can be cut to ground level and will re-shoot. Do check for nesting birds first though!

Q. I was surprised to read recently that berberis darwinii has edible berries. Is this true and if so, have the panel ever tried them?
A. The berries are quite sour but delicious in - for example - Iranian dishes. An Iranian cookbook is recommended! Proceed with caution if you suffer from diverticulitis, as berberis berries can cause problems.

Q. How do you prolong the life of a Christmas cactus? My cactus, which is kept in the conservatory, has purple-turning, withered leaves.
A. Water well, weekly between April and September. This species is a forest cactus, so does not require the hot, dry conditions of desert cactuses and the purple leaves are probably a sign of heat distress.

Q. My yew tree needs transplanting. The tree is 12 years old, approx. 8ft tall and had a trunk diameter of 4.5in. Please advise on the size of hole needed and the best time of year to move it.
A. Take a root ball of around 90cm diameter - the tree is likely to have deep tap roots, so will suffer. It may be worth reducing the size by cutting back foliage first. The move should be made in October to allow time in autumn for root growth (unless in wet heavy soil), but the whole process should be done over two seasons. Show less