Sue Arnold: Outsmarted by greedy West Highland sheep

It's my fault, of course, for wanting anything as silly and suburban as a garden

This time yesterday, I wasn't eyeing the people standing next to me at the No 49 bus stop outside Shepherd's Bush station suspiciously. I was on an island in Loch Linnhe talking about sheep. Whenever I'm back in London after an all too brief visit to the West Highlands I feel depressed, but never has that old saw about distance lending enchantment to the views seemed so appropriate or so true as now.

Yesterday, all I could think about was how to stop the damn sheep from getting into our garden, jumping on to our deck (yes folks, we have a deck but, scout's honour, we built it years before the blessed Titchmarsh on Ground Force made decking in British gardens compulsory) and eating my beautiful newly planted climbing roses and honeysuckle down to the root. Today, all I can think about is whether the next bomb will be at South Kensington, my nearest Tube station, and if when I go to the doctor next week - his surgery is on the far side of the station - I should make a detour and approach it from the Natural History Museum.

No point in speculating. Let's talk about hard facts, the most adamantine being this. There is no getting away from the fact that if you have a house on an island that's full of sheep, no matter how conscientiously you surround your property with stock-proof fencing and barbed wire and beg people to close gates and even draw up a comprehensive sheep-watch rota for distribution among your house guests, willy-nilly, the sheep will get in, jump on to your deck and eat you out of house and home.

It's my fault, of course, for wanting anything as silly and suburban as a garden. The whole point of having a house on an island from where you can see the Mull ferry leaving Oban, my husband reminds me when he finds me sobbing over the remains of my roses, is that it is wild. What's more, in case I hadn't noticed, in spring and summer it is covered with more wild flowers than any other island on earth. This is true, as a matter of fact. When we first started building our house on the Isle of Lismore 14 years ago, I'd bought a book from the local shop which, along with a lot of other useful information, revealed that at the last count there were 296 different species of wild flower on the island.

In Gaelic, Lismore means big garden, a description it richly deserves. We have to thank the Dalradian limestone, from which it is made, for its fertility. Owing to its rich soil, says one of my books, wild flowers grow to larger than normal proportions - field gentian, rock rose, mimulus, tutsan, ivy-leaf toadflax, wild orchid, cranesbill, yellow monkey flower, brooklime, speedwell, they're all here, so why on earth do I need imported flora to climb up my walls?

Habit, I suppose. I've grown up in houses with clematis curling round the door and roses climbing round the windows. You get used to fragrant smelling fronds poking through the hinges, spilling petals on to the sill. The first thing I did when the house was built was to plant a rose and a clematis at the front corner. This was before we had the deck, and a kind neighbour who happened to be passing suggested we put wire netting round them to keep the sheep off. Being a handy sort of fellow, he did it in five minutes and now, 10 years on, both plants have climbed way up to the roof. The wire netting disappeared years ago.

Had I given the matter sufficient thought before I'd planted this year's crop, I'd have realised that the reason the sheep haven't eaten my two vintage climbers is that they have grown so tall that their lowest leaves and flowers are out of nibbling reach. I didn't. I was far too busy choosing exotic raspberry ripple coloured floribunda roses and variegated honeysuckle to bother with detail.

You know the rest. What can I do, I wailed to my neighbour, a fisherman who recently inherited a croft and is now the proud owner of 120 sheep. Absolutely nothing, he said. Sheep can jump over, crawl under and wriggle through anything. He once saw a sheep roll over a cattle grid, an initiative that was immediately copied by the rest of the flock. Another time, a large sheep lay across a gully and allowed itself to be used as a bridge.

Hang on, aren't sheep supposed to be stupid? They sound pretty clued up to me, but then I'm just an ignorant townie who wants flowers climbing up her wall. Who needs roses anyway? An ivy-leafed toadflax by any other name would smell as sweet.