Like plants which must evolve or die, one of the most traditional Scottish charities is adapting to social change.

Sunday afternoon is the time-honoured diary slot to visit gardens opened to raise money for good causes, perhaps because there is nothing quite as restful as forsaking fork and spade to admire someone else's well-tended beds and borders. But patterns of work and leisure have altered radically since 1931, when Scotland's Gardens Scheme was created to provide pensions for members of the Queen's Nursing Institute. The nurses have long since become community nurses in the NHS, the charity has been rebranded as Scotland's Gardens and now gardeners in Fife are rooting out its sleepy image by opening at various times during the week, including some evenings, with a ticket giving entry to nine gardens, marketed as the Fife Garden Trail.

"Everyone is so busy trying to fit so much into the working week and they usually have family things to do at weekends," says Sally Lorimore, the Fife treasurer for Scotland's Gardens. "So this year people could visit a garden after work and then go for a pub supper. Often the evening is the best time because the wind has dropped."

A ticket for all nine gardens which can be used on different days is a recognition that when a single date is earmarked months in advance, visitor numbers will be dependent on the weather and whether there is a clash with other events. Visitors from further afield will be able to fit all nine gardens into the space of three days from June 11-12, while others can pick and mix.

Sally Lorimore takes an equally contemporary approach in her garden, Willowhill at Newport-on-Tay: "It is planted in a style Americans call colours with zing, provided by bold combinations such as purple and orange rather than the adhering to traditional colour schemes."

She says that when she and her husband took over the garden, her ambition was to have it looking good from May to September, leading to the creation of more borders, now packed with perennials. However, before that could happen, she spent a lot of time eradicating weeds and digging in "loads of manure". This hard work formed her gardening philosophy: "If you put in a lot of heavy work in spring, the summer will look after itself."

The key to ensuring blooms until September is to resist temptation, she says, while admitting she has not always practised what she preaches. She numbers herself among those who "go to the garden centre and buy things that are in flower in spring and by late July or August, there is no space for anything else". Her absolute favourite is the geranium Rozanne which is planted all over and gets marks for being long-flowering and, deep purple-blue with a white centre, contributes to the zing.

Boldness of a different kind is displayed by Julia Young, who has turned a former quarry at Blebo Craigs, a few miles west of St Andrews, into South Flisk garden, a tapestry of foliage and flowers, partly achieved by "dangling from a bit of rope tied to the fence".

Several times a year she is also to be found balancing in her boat in the pond beneath the quarry walls clearing ivy and nettles with a long-handled pruner.

Her dedication is obvious and her enthusiasm infectious: "I've got wonderful hellebores. Who hasn't? But mine are really nice." This pride is entirely justified. The garden is her project and for about one month every year she puts in six hours a day, although her husband, George, who runs his St Andrews pottery workshop from their home, helps with the heavy stuff.

With the weeds largely replaced with hart's tongue ferns and ivy with honeysuckle, there is less need for extreme gardening, although she takes to the boat to scoop weed from the pond, full of "hundreds" of golden orfe fish, some one foot long. Visitors this month can expect to see darmera peltata, a foliage, rhubarb-like plant with pink flowers before the leaves appear, the spectacular giant gunnera, whose leaves reach six feet across, lots of primula, including florindae, a yellow, cowslip-like species, and yellow flag irises. The wonderful fresh lime-green ferns are just about to open, while blossoms – cherry and crab apple – will soon burst into bloom.

Young is hoping her two magnolias will flower this year, the white flowers on the amelanchier will be out and irises will provide a cheerful burst of blue, white and yellow among the "crowning glory" of the rhododendrons, while the loss of three trees in a gale has proved an opportunity for new planting, including birches and rowans which provide woodland shade for masses of bluebells.

Angela and Peter Davey were familiar with the garden at The Tower above Wormit on the south side of the Tay before they moved into the house in 1988 as it had previously been owned by friends, yet it proved full of surprises.

"We didn't know it had a waterfall," says Angela, an indication of just how overgrown it had become. Now the restored water area, the result of a six-year project, is the garden's most unusual feature. "My son and his friend discovered the pond full of stones and covered in leaves, but it had once been a very important feature, with a bridge over it to a very elaborate summer house. We had to crawl under hedges to get to it, but we have relined the pond area and put a pump in to move the water around to make it into a waterfall again. There are now four ponds of different sizes."

Although she had some help on the major work, Davey has had the "good fun" of doing all the planting. Trees include white-barked birch and a weeping copper beech. She has a special fondness for the winter and spring-flowering hellebores, and has "gone a bit wild" by planting them throughout.

"Because we are on a slope which is mainly rockery, you are looking at them at eye level or sometimes even higher, whereas you usually have to lift them up to have a look at them." That's the topographical justification for her inclination to specialise in hellebores, but she also cites as a plus point that "you don't have to learn too many Latin names because they are usually just called double pink or double purple". The Tower garden has a variety of richly coloured hellebores: reds, some deep, almost black mauve, various shades of pink and an unusual green and pink.

Davey describes the planting as having evolved rather than adhering to a strict plan although sculptures provide focal points in the form of wrought-iron herons and cranes, a marble whale and a giant wooden apple. These blend the original paths with an area of mature trees and a rhododendron walk which should be in full flower this month, as a result of blooms delayed by four or five weeks. Whatever is in flower, this garden of just less than an acre offers a variety of interest and stunning views across the Tay.

Twelve years ago, Maggie and Malcolm Strang Steel began their garden at Greenhead of Arnot near Scotlandwell "with an almost blank canvas".

"We started with a fence to keep the rabbits out," says Maggie, "and built up some of the walls using the stones from the old courtyard buildings."

She didn't want long herbaceous borders which require endless weeding, so instead there are cottage-style borders with shrubs interplanted with bulbs and herbaceous perennials including delphiniums and astilbe, along with roses. One bed is filled with Buff Beauty and Margaret Merril, shrub roses with fragrant flowers, the first living up to its name with small buff of apricot flowers, the second a rich creamy white.

One of Maggie's favourite plants is lily of the valley which has taken a long time to establish. Her horticultural success is the result of mushroom compost, which comes from East Lothian by the lorry load, followed by an intense period of shovelling with the help of a "young, fit man".

The Strang Steels' new venture is a polytunnel to bring on vegetables from seed with the aim of prolonging the season in which they can supply home-grown produce for their bed-and-breakfast.

The 500 large country house gardens which were opened to the public in the 1930s were so spectacularly successful in raising money that the district nurses' pension of £20 was doubled. Today the scheme still offers an opportunity to visit grand private gardens but among the most popular are the smaller ones which owe more to hard work and enthusiasm than acres of specimen trees and shrubs or professional expertise.

The Fife Garden Trail is a larger-scale version of the village or town openings when a group of gardens (the record is 25) are all open on the same day. According to Lorimore, the Scottish openings raise one-and-a-half times as much per head as the English scheme – and attributes this to the fact that owners in Scotland can donate 40% of their takings to a charity of their choice, with the other 60% going to those supported by the organisation (which includes Maggie's Centres, National Trust for Scotland gardens, the Queen's Nursing Institute and Perennial, which supports gardeners). This year 209 charities will benefit. In the case of the Fife Garden Trail, 40% of the proceeds will go to the Association for International Cancer Research, based in St Andrews.

Entry to the nine gardens on the Fife trail is only by pre-bought ticket, £15 from scotlandsgardens.org.