This week on Gardeners World, Monty Don is searching for signs of our long-delayed spring in his garden at Longmeadow. Taking inspiration from his trip to RHS Garden Wisley last week, he will be planting up an alpine trough. Carol Klein is out and about looking at native celandines, Wordsworth's favourite flower; they grace our hedgerows and woods at this time of year. The wild strains are too invasive for most domestic gardens but Carol finds a number of cultivated varieties that should suit most of us. And, if its colour you are after, then enjoy a sneak preview of summer when we visit agapanthus enthusiast, Michael Dedman, in his Essex garden to see his prized collection of these beautiful African lilies at their very best. Back at Longmeadow, Monty's hoping the soil will have warmed up enough to finally allow him to plant his potatoes.