Boasting a premium build that offers years of garden design style, the Premium 3.6m Ultima Pergola is the perfect garden feature to define your outdoor dining area, demarcate a garden pathway, or provide a shady seated nook. This premium pergola from Forest Garden is our most robust wooden pergola yet. Manufactured from pressure-treated timber, the pergola comes with a 15-year guarantee against rot and fungal decay.. To keep the pergola secure in all weathers, the posts can be sunk into the ground.