My spring flowering beds include a mix of tulips, daffodils, crocus, hyacinths, hyacinthoides, alliums, leucojum, and various types of lilies. I have been using this fertilizer for years to help all of my bulbs to stay vigorous and naturalize well. Since my other lilies are growing so well (and blooming madly), I would assume that tree lilies would also experience the same benefit. You can enhance the tree lily planting area by mixing some well-composted cow or chicken manure into the soil before putting in the bulbs, and then sprinkle some of the Espoma fertilizer on the surface of the soil per package instructions to provide continued slow-release feeding throughout the season.