e-mail Jane Owen with your gardening questions: jane.owen1@timesonline.co.uk

I have an azalea and a crab apple both of which have lichen on them. Is this a good or a bad thing for the plant? Do I need to get rid of the lichen and if so how? Dereck Fowles, Drymen

They do no harm at all and simply add beauty to your trees. They are ancient organisms, a mixture of fungi and algae and they are self-sustaining. The good news is that they are an indicator of unpolluted air although I imagine that you are already aware of the fine, fresh air in your area.

The old barn behind us is about to be developed and we will be looking straight in their windows. We have the maximum height of wall allowed (2m) between us but the ground between dips, so we need screening trees that will reach a height of say 15 feet, preferably evergreen and reasonably quick growing. Our side of the wall is southwest facing, theirs north east. We get on well. Many thanks for your help JM

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I’m glad to hear that you get on with them because co-operation will open up all kinds of options. All the same you should all be aware of the legislation on hedges should there be any future disagreement. . Check www.nuisancehedge.co.uk for more information. If there is enough room to plant a few birches on both sides of the wall you will have gentle screening without blocking too much light. In winter you can add lights to the trees. The advantage of have the same trees on both sides of the wall is that the boundary will blurr and you will have the impression of grounds that go beyond your wall. If you want a thicker, evergreen screen, evergreen oak is a good bet. It can be trimmed to whatever height you want but it will certainly come under the government’s hedge legislation. The same is true of a ‘flying hedge’ of anything from hornbeam to Portugese laurel. Flying hedges are made from trees with bare trunks and then a hedge-like canopy. They can be bought ‘off the peg’ for a lot of money – but they look stunning and give instant screening at exactly the height you want. The same people who supply flying hedges will also supply mature trees – at a price: www.ewburrownursery.co.uk, www.fairweathers.co.uk, Architectural Plants and www.tendercare.co.uk .

On the other hand it might be simpler and faster to add trellis. Use bespoke, heavy-duty trellis and find some pretty finials to put on top of each support post. Then you must choose your plants carefully because, on the whole, plants will flower on the sunny side of boundary leaving you neighbours flower-less. Trachelosperumum may be persuaded to flower on both sides and so will some clematis and hydrangeas but the truth is the southern side will always get the best of the flowers.

A couple of months back you had an extended feature on trees. It talked about 6ft Scots Pines being available to buy and quoted a modest price. I have hunted across the internet and via Plantfinder, but I have not been able to find anyone who sells them. I presume that whoever wrote the feature must have had information about suppliers and I wonder if you could share this with me? Leslie Forsyth

The Woodland Trust has a good supply of high-quality Scots Pine or Pinus sylvestris and, if you buy through them, you will have the warm glow of knowing that you have contributed to an excellent charity. Their prices look pretty good to me.

Some crocuses, late Christmas presents, have just arrived. Sprouting and yellow. Is it worth planting them out? Caroline Spender

Yes, but slot them into a pot of damp compost in a cool conservatory before putting them into the open – it will give them a chance to acclimatise. Also, water them with room-temperature water to begin with.

How can I prevent my poinsettias from loosing their red leaves as they did last year? This year I bought new ones with red leaves. Gordon Boyce

You can’t without an awful lot of hassle and special lighting equipment. It is cheaper and better for your mental health to buy new ones every time the red bracts (leaf-like red bits) fall off or go green/yellow.

We have a courtyard garden just outside Doncaster. It faces south with walls on three sides. I say we can grow an olive tree but my husband says this is impossible. Joanna Botham

So long as you use a fast draining compost the tree will be fine. If you plant it in a pot it may need protection in frost. If you plant it into the soil it should manage without protection.

Something is eating the rocket which self seeded around the garden. What is it? Name and address withheld

Without a description of the damage it is difficult to know but slugs, pigeons and even sparrows are highly likely.

I’ve got a strange statue of a chap covered in mud – how can I find out if he complies with Food Hygiene scores? Paul

I have included this email to give you, dear reader, some idea of the barmy ramblings that are sent to me regularly. I am too baffled by this question to come up with any answer but, if any reader can fathom Paul’s problem and come up with an answer I’d be very grateful.

e-mail Jane Owen with your gardening questions: jane.owen1@timesonline.co.uk

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