Summer Gardens

The passion flowers blossomed right on schedule, about an hour before the garden tour was to start. ''We try to have something new blooming every week, but this was an extra bonus!'' Katherine Lombard chirped as she dashed off to check on her peach blush lilies.

Flower and vegetable gardeners in this south-of-Boston suburb, like their counterparts in communities throughout the United States, look forward to summer garden tours with an anticipation cultivated during long hours of weeding on hands and knees. Like seed catalogs in December, garden visits in July offer the promise of pointers for growing taller delphiniums and ever more colorful coreopsis.

Mrs. Lombard's perennial borders were a knockout favorite on one recent tour to benefit a local natural science center. Tucked under flowering plums and feathery white pines, her scalloped splashes of pink dahlias, yellow gallium, and purple globe thistle drew breathy raves from each new arrival.

''I'm just the groundskeeper, mother's the designer,'' Mrs. Lombard's daughter, Joan, told inquirers. She also found mischievous delight in explaining why her mother had never joined the local garden club: ''She decided the members spent more time shopping for clothes for the meetings than they did in their yards.''

Gardening as a family project has deep roots in New England soil, and farther down the road Sylvia White was busy taking visitors on a tour of the English country garden that was originally planted by her husband's grandmother. As she pointed out a 40-year-old lavender plant and peonies that dated back to 1900, she chatted about one daughter who used to work as a conservation agent in a neighboring town and another who is married to a landscape architect. ''My father was an enthusiastic gardener, and my mother-in-law taught me the rest of what I know,'' she added. ''Then when my sister moved in a few years ago, she started a lovely herb garden. I guess it runs in the family.''

Mrs. White spelled out the names of her less familiar plantings for her many curious visitors: ''That's s-c-a-b-i-o-s-a s-t-e-l-l-a-t-a - I grow it for its unusual pods. And over there is some a-m-m-o-b-i-u-m - I first saw it growing in Claude Monet's garden in France.''

At the Heineman family gardens, Harry Heineman made the rounds of the perennial and vegetable beds dressed in blue shorts and open-necked shirt, a well-worn copy of Wyman's Gardening Encyclopedia tucked under one arm. Near the fruit orchard in back of the garage, his three children had staked out their own displays. Hand-crayoned signs proclaimed ''Anna's garden,'' ''Sarah's garden,'' and ''Lincoln's garden.'' Lincoln, aged 3, has been raising tomatoes and beans for a year now and had his sign specially designed for the tour by older sister Sarah, aged 9.

Mr. Heineman's flowering magnolias and camellias were an obvious source of pride, but one also could not help noticing the kind of reward every gardener appreciates most at the end of a day in the compost heap. There in a grove of shady pines, surrounded by ankle-deep myrtle, hung a luxurious king-size hammock.