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Correspondence Edition

Peter Gibbs hosts the horticultural panel programme from Kew Gardens. Anne Swithinbank, Chris Beardshaw and Matthew Wilson answer the audience questions.

Produced by Howard Shannon
Assistant Producer: Hannah Newton

A Somethin' Else production for Ö÷²¥´óÐã Radio 4.

Available now

43 minutes

Last on

Sun 30 Aug 2015 14:00

Questions and Answers

Q - I live in Bristol. Can the panel advise as to whether it would be feasible to grow fruit trees in a hedge like format? Do I need to have a different species as a basis - like willow or similar then integrate fruit trees into it. I'd love to grow apple, pear, plum, damson, sloe and grapes, will it be possible to form a sturdy barrier whilst have productive fruit trees/ plants? The border faces north/ south but on the south face there is a wooded area behind. In front I have grass.

Matthew – You just have to moderate your expectations on yield – the fruits aren’t necessarily to be pretty, they may well have more diseases, and be smaller fruits.Ìý But it’s perfectly viable.Ìý

Anne – I’d be tempted to put shorter plants in between them – something like gooseberries so there is an understory.Ìý And you could summer prune the apple trees so they don’t become too congested.Ìý

Chris – If you want to make it impenetrable then think about using something like sloe as your base and then allow any fruiting trees to stand as standards through your hedge.Ìý Also, things like bullace would be good, the gages, and the russet apples.

Joe Archer (Kew’s Kitchen Gardener) – Important to make sure you’re not on a huge root stock – so something like an M9 or an M26 so you could keep on top of them.

Ìý

ÌýQ - Can I grow Quinoa on our allotment? ÌýIf so, can you give us some idea how? And can I grow it from the stuff sold in the supermarket?

Anne – That would depend on how it’d been processed but you probably could.Ìý But it is easy enough to buy the seed anyway.Ìý Should be easy to grow but will be difficult to harvest.

Joe – We grow it here.Ìý It often gets mistaken for Fat Hen.Ìý We start them off in the greenhouse, plant them out in a 9cm (3.5inches) pot after last frost, and within 4-5 weeks you will get a 1m-1.5m (3.3ft-4.9ft) growth.Ìý Harvesting – the seeds can start to germinate on the plant so you’ve got to catch them when they start to ripen.Ìý Also, you might want to steak them because they can get top heavy.

Ìý

Q - Last year I got a greenhouse and moved my rather small but quite old fig into it. The pea sized fruits got growing this spring and I had nearly 40. They now seem stuck though at about 5cm long, not ripening and 3 or 4 have turned yellowish and fallen off. There is now a new lot of small figs developing. Will the larger ones ever ripen? Should I remove the smaller ones, or the larger ones or am I just being impatient! The fig is a lovely one, not Brown Turkey, but more like a green one with lovely red flesh from eating the very few that I have had over the years, when it was outside in its pot.

Anne – When they’re outdoors you generally remove all the medium-size figs in the autumn and you leave only the pea-size ones so they have all the energy of the plant in the spring.Ìý Inside I reckon you’ve still got time for these to ripen – give it time!

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Q - I garden in Horncastle, Lincolnshire on the edge of the Wolds. I have a Cercis siliquastrum (Judas Tree) grown as a standard tree in the open and a Cercis chinensis grown as a shrub sheltered by, but not against, a south facing wall. Both plants have suffered random dieback of branches, about 20 - 30% shed their leaves prematurely last Autumn and failed to flower this Spring. The die-back is on the West side yet our prevailing cold winds are easterly. There doesn't appear to be any sign of insect pests or disease, just dead wood. The soil is light and free-draining and just the acid side of neutral.

Tony Kirkham (Head of the Arboretum) – I would suggest that the growing conditions are okay.Ìý Cercis Siliquastrum is normally grown as a multi-stem so training it as a standard might be making it moody.Ìý Cercis chinensis isn’t easy to grow – it’s very fussy and choosy.Ìý The symptoms suggest they’ve been planted too deep and through the year that stresses them.Ìý They are used to a hotter, Mediterranean climate too.

Anne – It might just be because of a particularly cold winter within the last five years or so – sometimes it takes a while to visibly affect a plant

Tony – Could be an idea to cut it down to ground level and then let it grow as a multi-stem.

Ìý

Q - I have two 8 ft (2.4m) apple trees in my garden, one of which produces apples with black spots ... I’m worried that kids pinch the apples and will poison themselves .... what should I do?

Anne – It’s probably ‘bitter pit’ in the apple that is caused by a calcium deficiency – it won’t cause you any damage, just not nice to look at.

Tony – It could be apple scab and this year’s been bad for scab because of the warm, humid weather.Ìý

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Q - Last Autumn, we cut down a cherry tree that had been planted by the previous tenant of our allotment, as it was not on dwarf root stock and was taking up too much water and not earning its keep with fruit.

Due to its location in the fruit cage, we were not able to use the winch the remove the stump and now have major problems with suckers.

Would it be safe to use stump killer, as there are raspberries and blackcurrants all around the tree stump. How else can we kill off the stump, please, without affecting all our other fruit?

Chris – Sadly the suckers are often more vigorous than the original tree.Ìý I wouldn’t use a stump killer – I would dig it out, hard work but worth it.Ìý You could use polythene mulch for the past few but I’d get in with a spade, a pick, and an axe and go to work on it!

Anne – I think you’re past the point of using a stump killer.Ìý Dig them out.

Matthew – Whenever I’m taking out trees I never flush cut them down to the ground.Ìý Leave 1-1.5m (3.3ft-4.9ft) of stump to give you some leverage.Ìý Makes it much easier.

Ìý

Q - I have a very healthy camellia bought in Woolworths about 40 years ago. [It was just described as 'red', is a proliferous flowerer and as tough as old boots]. It is a shady shrubby border [behind a dwarf apple tree planted in the lawn].

It is kept pruned down to about 6ft (1.8m) [although it has been neglected for the past two years when the site was given over to the builders to demolish our old house and build a new one]. Some years ago I crown lifted it to allow woodland plants to grow underneath but it is now far too dense. Can I cloud prune it? If so when do I do it and how do I go about it?

Tony Hall – Cloud pruning a camellia is not often done and I wouldn’t recommend it in a shady border.Ìý I would thin it out a bit in the spring after flowering

Chris – I agree – you risk losing the flowering capability.Ìý So thin out but don’t dig around the base – it’s very shallow-rooted

Matthew – Although you do see camellias grown as standards they’re really designed to be grown in pots in relatively high light level conditions.Ìý

Anne – I’d say yes! It’s already quite old, it’s been kept to 6-foot so it’s used to being clipped quite tightly.Ìý What it needs now is a good watering and then mulching, and probably a feed in the spring too.Ìý Prune with secateurs not with a hedge trimmer

Ìý

Q - Do soft privet clippings provide good green material for the compost heap?

Tony – As long as they are the soft clippings I think you’ll be fine.

Ìý

Q - There is a current trend at weddings where table flowers are stored in varied and quirky jam jars. ÌýI, as an eager learning gardener, rather fancy the idea of growing small pots of flowers from bulbs despite advice from family members that this won't work. ÌýThe wedding is the end of June 2016 and we have no particular colour in mind. ÌýCould you recommend anything that is easy to grow and guaranteed to be in bloom over this time?! PS: I am currently without a greenhouse if this influences choice?!

Anne – I think it’s doable but it will take effort.Ìý Best bet is things like sweet peas and ammi.Ìý Down south I’d leave sowing til October, up north I’d say September.Ìý Roses will also be in bloom.Ìý Larkspur too.

Matthew – Not a great time of year to be growing bulbs.Ìý And high risk to do with the other stresses of the wedding.Ìý Go out and get picking – but be careful picking Cow Parsley as you can get invaded with caterpillars when you do!

Chris – I would have a go at bulbs.Ìý For a blue theme try Agapanthus, the trick to guarantee flowering is to plant them at different stages (ie successional planting).Ìý Agapanthus campanulatus which is the border variety is pretty tough and reliable.Ìý Also, I’d be tempted by Nerine sarniensis – comes in shades of pinks and whites and oranges.

Tony – I think bulbs are tricky but there are some that could work.Ìý Perhaps a small patio lily or lavenders or patio roses.

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