Peter Gibbs hosts the horticultural panel programme from Bushey in Hertfordshire. Bob Flowerdew, Anne Swithinbank and Pippa Greenwood answer the questions from an audience of local gardeners.
Produced by Hannah Newton
Assistant Producer: Laurence Bassett
A Somethin' Else production for BBC Radio 4.
Questions and Answers
Q – What can I do to get ‘Snake’s-head Fritillary’ established in my garden?
Bob – They are a native plant found most in sunny, open meadows that are moist. If you’re on heavy clay, you’ll want to lighten it with loam.
Pippa – Improve your drainage dramatically – they’ll be rotting out in the winter months
Q – I was given a beautiful red Amaryllis for Christmas. How do I keep it and get a blossom next year?
Anne – It is possible to keep them in growth all year round – keep it in good light, well watered, with some feed and it will carry on being green and lapse into a summer flowering pattern. Or you could let the bulb dry off in the summer and then get it going again in early autumn. Keep it indoors.
Q – I’m looking for small shrubs or perennials that will tolerate wet winters but will handle a good summer too. Recommendations?
Bob – Make sure the drainage is good for a start. When you’re planting dig the hole two or three times wider and deeper than you’d imagine, use a fork to make holes in the bottom of it, and then mix in something loose (gravel, sand, compost etc) with the soil when planting. Also, plant on a slight mound. Get the conditions right and you can grow almost anything you want.
Pippa – Sarcococca confusa (the ‘Winter Box’) does well in these conditions. Japanese Anemones seem to like it too. Iris unguicularis is good, as are Peonies.
Bob – Buy smaller plants. It’s easier to establish smaller plants.
Pippa – Also it’s worth applying foliar feeds when establishing – for some reason feeding through the leaves stimulates root growth.
Q – I’ve been growing Cosmos from seed for the last two or three years but they always come up thin and lanky. How can I make them more bushy?
Bob – If you’re growing under glass it can get very hot unless you have good ventilation and that could be the cause.
Anne – Sow them into a seed tray and spread them out. Then when they germinate you can get round each one easily. When you can handle them I would dibble each one out and put each one into its own 9cm (3.5 inch) pot. To transplant a seedling hold it by its seed leaf and if it has a long stem you can sink it into the ground. Or sow direct at the beginning of May. Leave a foot (30cm) between each plant.
Pippa – They need a bit of rough and tumble to replicate outdoor conditions. If you do it under glass again get a sheet of paper and brush across the top of the seedlings to replicate the movement of the wind.
Q – My Salvia ‘Hot Lips’ is getting a bit thick. Should I prune it vigorously or continue to just trim the top of it?
Anne – I think you can go down a good two-thirds without causing them any damage. I grow a Salvia called ‘Lemon Pie’ and I take that down by two-thirds to stop it becoming woody. Now is the time to do it too.
Pippa – If you get any more be a bit more brutal sooner on in its life
Q – I have a small Rhododendron bush which has flowered well for the past seven years. Overnight the leaves drooped and lost their shine and colour although the bush is full of buds. The roots are not dry – what can I do to save it?
Pippa – When something dramatic like this happens I always think something has happened at the base of the plant. Take a look at the roots because I think you’re either going to find dead roots or perhaps Vine Weevil grubs, which love Rhododendron roots.
Anne – I think that we’ve had bad conditions for Rhododendrons this year – dry autumn, wet winter, cold spring – and that could have had an impact
Q – What are the best roses to grow in containers?
Anne – They need big containers and lots of pruning. Things like ‘Flower Carpet’ or ‘Ballerina’ would be full but they don’t have any scent. Don’t go for a climber as it’d be too much work.
Pippa – Go to a specialist nursery and get top quality plants
Q – How do I grow good size onions?
Bob – I start mine off in late-February in little cells to get the roots going and plant them out in March. The number of leaves you’ve got by May will determine how big the onions are going to be. Also, space them well – 6 inches (15cm) apart each way will do. They don’t like a loose soil and I’d feed them with blood fish and bone meal or pelleted chicken manure and rake it into the top bit of the soil.
Anne – Try growing them in shallow pots with big tops (60cm (23.5 inches) diameter) with lots of compost.
Bob – Or use a wheelbarrow!