A woody plant is a plant that produces wood as its structural tissue. Woody plants are usually either trees, shrubs, or lianas. These are usually perennial plants whose stems and larger roots are reinforced with wood produced from secondary xylem. 

Lloyd and McCown medium was originally developed for the culture of shoot tips of Mountain Laurel (Kalmia latifolia). The medium has since become a standard for the culture of many woody plant species. The formulation is a nutrient blend of inorganic salts, vitamins and amino acid. Potassium Nitrate has been eliminated from this medium and replaced with Potassium Sulfate. The levels of ammonium nitrate are 1⁄4x compared to Murashige & Skoog. Nitrogen is also provided by calcium nitrate.