Antonyms of deciduous:
evergreen, semi-evergreen, half-evergreen, lasting, cone-bearing, persistent, coniferous, lifelong, continuing, durable, imperishable, indefectible, indestructible, ceaseless, dateless, deathless, endless, enduring, eternal, everlasting, immortal, long-lived, permanent, perpetual, timeless, undying, unending.
Examples of usage:
  1. I had rather Justin beat me into submission and mental tranquillity and that I bore him an annual- probably deciduous- child.
    "The Passionate Friends", Herbert George Wells.
  2. Diaphragm thin; tendrils few, or if present, weak, usually deciduous.
    "Manual of American Grape-Growing", U. P. Hedrick.
  3. Here a scattering group of tall pines, a few thick hemlocks, and a young growth of miscellaneous deciduous trees fill up the space between two rather steep banks.
    "Butterflies Worth Knowing", Clarence M. Weed.