Gardening: the year ahead.

After the dust settles on tonight's excesses, it will be time to make plans for the coming year. You might solemnly prepare a well-thought-out schedule, as advocated by an 18th-century gardening enthusiast. "Thinking is of more service on carrying on of all business than is commonly considered or practised in our country," wrote Cockburn of Ormiston to his gardener on January, 3, 1744, and the sentiment rings just as true today. The gardener was given little chance of thinking for himself as he ploughed through his master's endless and petty instructions, but we are free to do so.

Sitting indoors and gazing out on the frosted garden provides the perfect scenario for this. Last year's faults and imperfections are happily concealed and, as ever, fantasy might just outstrip what's possible.

A small mound of neatly sifted soil quickly brings me crashing back to reality as I remember the devastation wreaked by an army of moles. Yes, 2011 was the year of the mole and we had many more than the typical estimate of 2.4 moles per hectare. A retired farmer comes here for around four trapping sessions a year and he reliably catches five or six every time. All my rich organic soil, teeming as it is with fat worms, is an irresistible magnet for moles, and an established network of mole runs makes life easier for newcomers. My trapper's fees – £7 a head – are a price worth paying.

Most of the devastation was in the kitchen garden. The little wretches dug out their runs, and even when I destroyed these excavations, a new passage appeared within 24 hours. Cabbages and sprouts, plants that demand firm soil, were worst affected. Even a short row of peas hit the dust.

I'll resist filling the page with further mole misery, since it was the erratic weather which really took the biscuit, testing so many plants to the limit. From my own garden and the many readers' emails I receive, I know exactly how much damage has been done to normally resilient shrubs. Two harsh winters in succession were more than many plants could handle, then a long, dry spring, a sunless summer and a ludicrously mild autumn have caused further stress.

Whatever your plans for the year ahead, the weather is the great unknown, so I always focus my January reveries on the big ideas that aren't weather-dependent. I start with garden layout: the beds, paths, seating and parking areas, boundaries and divisions within the garden. Much as I love my garden, I always ask what I want from it and what I need to add or change. Structural harmony is critical. I live in an old stone cottage surrounded by fields and hills, with an ancient dyke defining the main garden. Plans for raised beds, border edges and new steps must be in stone, not brick.

This year's ambitious goal is to benefit from a horticultural tragedy. The wonderful vanilla-scented Clematis montana "Wilsonii" that was such an important feature was one of last winter's casualties. As the clematis expanded and the road-lined hedging grew taller, that part of the garden had gradually become shadier than we wanted. So change is essential. The young elm that acted as my shrub's climbing frame will go; the hedging – a mix of ash, hawthorn, wild plum and willow – will be reduced; and yet another new bed will be constructed.

I'll need to scour the burn and garden for suitably-shaped stone. I'm constantly amazed at the number of useless triangular ones I keep unearthing. Nonetheless, the duck run is a rich seam, since busy beaks have helped erode the soil, revealing fine pickings.

Getting topsoil for a new bed is just as challenging. Most builder's merchants sell it, but you should only accept a load after checking it's not too stony, riddled with clay, or thin and gritty. A further worry is that the soil might be contaminated with fungus or synthetic chemicals. You could bulk up with municipal green waste, but this soil conditioner will quickly run out of nutrients. One part soil conditioner to four parts soil works well. I'll keep my topsoil in-house by using some ditch clearings and compost.

The planting's the exciting bit. A low-lying bed in partial shade that will form part of the herb garden will be ideal for mint, chives and rocket.