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Peter Gibbs and the panel are in Lambeth. Anne Swithinbank, Matt Biggs and Pippa Greenwood field the horticultural questions.

Peter Gibbs and the panel are in Lambeth. Anne Swithinbank, Matt Biggs and Pippa Greenwood field the horticultural questions.

This week, the panellists offer advice on overwintering asparagus, the best varieties of cactus to grow from seed, and how long you can leave potatoes before lifting.

They also discuss mulching a herbaceous border, suggest tree ideas for a windy spot, and offer up tips for growing fruit and veg on a roof terrace.

Matt Biggs takes a turn around Lambeth Palace Gardens, one of the oldest continually-cultivated gardens in London.

Producer: Dan Cocker
Assistant Producer: Laurence Bassett

A Somethin' Else production for Â鶹ԼÅÄ Radio 4.

Available now

43 minutes

Last on

Sun 28 Jan 2018 14:00

Fact Sheet

Q – We’ve got asparagus frons in our allotment – how should we nurture them over the winter?

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Pippa – Asparagus benefits from a winter mulch.Ìý Look out for asparagus beetles and get rid of them before mulching.

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Matt – The mulch will protect the crowns

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Anne – Then keep them free from weeds

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Q – My daughter would like to grow a cactus from seed.Ìý Can you recommend a good variety?

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Anne – ÌýRebutias or Mammillarias are good to go for because they are quite quick.Ìý Get a free-draining seed compost, sow in spring and put it on the windowsill.Ìý Another option would be Lithops (actually a succulent but great to grow).

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Q – How long after the potato tops have died back can you leave them in the ground before lifting?Ìý I’ve got ‘Charlotte’s’ and ‘Northumbria Delights’.

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Pippa – No hard and fast rule.Ìý Depends on slug population.Ìý I try and lift asap because I have lots of slugs in my heavy clay soil.Ìý ‘Charlotte’ potatoes don’t get slugs too badly, so I left them longer last year.

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Matt – If you leave them they’re just taking up space when you could be planting something else

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Anne – Some varieties change flavour the longer you leave them.Ìý Worth experimenting a bit.

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Q – When should you mulch an herbaceous border?

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Pippa – Depends why you’re mulching.Ìý I would do a bit in both winter and spring.

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Matt – I would leave the stems on the top over winter and then cut that back and mulch just before they start to grow again

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Pippa – Penstemon would benefit from a winter cover

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Anne – Alstroemerias and Dahlias too.Ìý But I would mainly do it in the spring.Ìý I would only avoid if you were wanting to show off your Hellebores and Snowdrops.

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Feature:

Sage

Hyssop

Lemon Verbena

Liriodendron

Magnolia

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Q – What tree can you recommend for a 30ft (9.1m) square, enclosed, east-facing garden? It takes extremes of heat and gales.Ìý It will be in a large raised bed.Ìý

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Matt – Arbutus unedo.Ìý

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Anne – I was thinking of Elaeagnus ‘Quicksilver’.Ìý

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Pippa – Tamarisk.Ìý I might try an ornamental Hawthorn.Ìý

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Q – I am down-sizing to a roof terrace.Ìý What fruit and vegetables can I grow?

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Pippa – You can grow just about any vegetable in containers.Ìý Peppers would be good.Ìý Beans, carrots, beetroots, salad crops.Ìý I wouldn’t try brassicas or sweetcorn.ÌýÌý 45cm width and 45cm depth (18 x 18 inches) would be a good size container.

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Anne – Try the French bean Jimenez.Ìý Borlotti beans too.Ìý The Shiraz Mangetout.Ìý I would also try herbs like sage, thyme, rosemary and oregano.Ìý Fresh mint in another bed.

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Matt – Go for fresh-tasting crops.Ìý Patio peaches and apricots would be good too.Ìý Try Hestia in pots.

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Q – I want to create a small wildlife pond in my garden.Ìý Suggestions please.Ìý

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Anne – I’d put a liner in to get the sloping edges which will entice wildlife.

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Matt – I’d go down to about 2ft (0.6m) and then go for native plants

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Pippa – If you go down to 2ft (0.6m) then you’ll help avoid the water warming up in the summer and the ‘pea souper’ effect that afflicts a lot of shallow ponds.Ìý Try and incorporate planting shelves to get different levels.

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Q – Could you suggest plants for a balcony or for indoors that will help purify the air?

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Pippa – Boston Fern and Spider plants

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Anne – Peace lilies.Ìý All indoor plants are good at removing indoor pollutants

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Matt – Mother-in-Law’s Tongue.Ìý

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Anne – Get some containers and put a mixture of plants in.Ìý For example, a Calathea, a Piggyback plant, and a fern.Ìý

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