Eric Robson and the panel pay a visit to Exeter. Bob Flowerdew, James Wong and Anne Swithinbank answer the audience's horticultural questions.
Produced by Dan Cocker
Assistant Producer: Laurence Bassett
A Somethin' Else production for BBC Radio 4.
Q – How can I get rid of Nostoc slime on a garden path?
Anne – I would use a stiff broom or you could put down a garden disinfectant but it will likely be washed away by the rain.
Bob- It is living on the organic material such as leaf mould. I would dig out the gravel down to about 6 inches (15cm) and disperse it amongst the garden plants and replace the gravel in the path.
Q – I have potted an Avocado plant that grew from kitchen waste in the garden, it is now growing in the poly tunnel. How do I look after it?
Bob – The smaller avocados grow hardier plants and so it would be fine in a poly tunnel. I would bend it over and tie the top to the bottom like a wreath and every time you see long shoots, wind them in to stop too much growth.
James – In warmer parts of the country they should survive outside for parts of the year. Keep it in a warm room with as much light as possible in the winter. In the United States you can buy the ‘Mexicola’ variety which is bred for its hardiness.
Q – What is the best climber for autumn colour?
James – I recommend Trachelospermum (confederate jasmine). In the autumn it turns a deeper colour and it’s evergreen so the colour lasts for much longer.
Anne – I would say Vitis coignetiae (crimson glory vine), it has enormous leaves and climbs well over large structures in the garden. The colours come quite early and are really fiery.
Bob – I like the Vitis vinifera (strawberry grape), it has a sweet taste and fills the garden with a wonderful smell.
Q – What is the best way to get parsnips to germinate?
Bob – You can do station sowing where you make a small soil indent every foot and sow three seeds 1 inch (2.5cm) apart in a triangle and put a plastic cylinder over them, such as a cross section of a plastic bottle. You can also plant an actual parsnip and let it flower and self-seed because it does a much better job.
Q – I have spaces in my brick wall that I would like to plant in to help remove the weeds, what plants do you recommend?
James – I like the Pratia pedunculata (white star), it grows very small white flowers that look like stars. It is really resilient. Also I recommend Soleirolia soleirolii or ‘mind-your-own-business’ plant, it looks like moss and it’s very hard to kill.
Bob – There is a yellow version of Soleirolia soleirolii. It is also important to get rid of the dandelions, I would use boiling water.
Q – What advice would the panel give to maintain good soil structure, particularly in a kitchen garden?
Bob – It is as basic as adding a lot of organic material to help balance it. Seaweed also really helps all types of soil.
Anne – Once I have done the initial dig of the plant bed, I like to not tread on the soil.
Anne – Fern called Davallia mariesii (squirrel’s foot fern).
James – Wolf’s Bane or Monk’s hood (Aconitum napellus) which is toxic.
Q – How can I properly prune Forsythia so that it produces abundant flowers?
Anne – At the end of the season I would thin it out and remove around a third of the shoots. Leave some to mature and they should flower the following year.
Bob – If you pull the tall growth over and tie them, they will grow into arches and stop the apical dominance. You should get buds breaking all along the bent stems. It would be good to give it some wood ash and feed too. You could also buy a ‘Beatrix Farrand’ forsythia.
Q – I planted a Callistemon citrinus ‘Red cluster’/ ‘Bottle brush’ in full bloom, I had to move it and now it only flowers early autumn rather than summer. How can I change its flowering cycle back?
Anne - It may just be the variety which flowers later in the season.
Bob – If it’s next to a wall it might be too dry. If you give it more moisture earlier in the year it may flower sooner.
James – Sometimes Zantedeschia aethiopica (‘arum lily’) flower in the winter because it’s too hot in the summer. You could try and move it to make it the environment less shady.
Q – Next spring we are planting a white garden; how can we plant to put off the rabbits?
Anne – They often leave peonies, hellebores alone. They’ve not eaten penstemons or hydrangeas. You will need to fence off part of you garden.
James - Japanese anemones, Brugmansia (angel’s trumpet), Digitalis purpurea (foxglove).
Bob – I would net the garden.