t is the summer solstice so the days are the longest of the year and the sun is at its highest. With the garden growing before our eyes, Monty Don is in his borders replacing plants like wallflowers that are past their best with other annuals that will give colour right through to autumn. Carol Klein will be answering a viewer's letter with advice on gardening to provide a habitat for wildlife. Joe Swift picks up design tips from Kelmarsh Hall, whose 18th century garden is the epitome of the effortless, relaxed, English country style. And in Monty's vegetable garden, the first fruit and summer vegetables are ready to harvest.