Homeowners have been warned not to let thieves spoil the view from their conservatory.
An M&S Home Insurance survey found that as many as two-thirds of Brits have not checked their policy to see if their garden is covered.
This could present a problem to green-fingered households if they are targeted by criminals as the study also discovered that the average UK garden has more than £700 worth of plants, bushes, trees and shrubs.
However, this figure does not to include other items such as ornaments, barbecues and furniture.
British Summer Time officially began on Sunday (March 29th) and insurance companies have suggested that criminals may target gardens during the warmer months.
M&S insurance manager Judith Roberts explained thousands of pounds are spent each year securing homes against theft.
"However, despite the huge amount of time and money invested in many gardens, security levels are often very poor, making them an attractive target for thieves and vandals," she said.
Both Halifax and Saga have recently warned their customers to be aware of garden criminals over the summer months.