Lettuce - Tree We always plant this lettuce, as it is so hardy year round. $3.00 Out of stock. 0 in your basket View Basket Checkout NZH An outstanding green oakleaf shaped lettuce. Holds well in summer and winter. Continues to taste good even when it starts to bolt, hence the name “Tree.” Sow in early Spring, repeat monthly for continuous supply. Sow into trays, prick out at 4cm diagonal spacing when true leaves emerge. Transplant into fertile soil at 20cm diagonal spacing. 200 seeds.