Saw palmetto (Serenoa repens) may be the toughest weapon in your garden arsenal. As the most common U.S. palm, this shrubby native’s sharp spines pack an unwelcome surprise. Although saw palmetto’s growth is slow, it is a long-lived plant. As a seed-bearing plant, it produces flowers to reproduce sexually, but it can also multiply itself asexually by its spreading rhizomes.
Habitat and Range
Saw palmetto grows along the Southern coastal areas in U.S. Department of Agriculture plant hardiness zones 8 through 10. Its range extends from South Carolina to Texas, where its diverse habitat includes sand dunes and pine forests that support varying light conditions. Saw palmetto’s high salt tolerance makes it adapted for growing along coastal areas. Once established, plants tolerate drought and moist soils, but flooded areas can inhibit seed germination, which retards saw palmetto’s growth cycle.
Flowers, Fruits and Seeds
Saw palmetto produces white flowers, which grow in panicles from stalks that form in the leaf axils. Insects are the primary pollinators for saw palmetto flowers. Successful pollination results in the formation of greenish-yellow fruits that ripen to bluish-black, resembling small olives that cascade from the flower stalks. Birds and other wildlife relish the fruits and excrete the seeds, often spreading them over large areas. Because the hard seed coat is impermeable to oxygen, which is needed for germination, the seed coat must deteriorate naturally before roots and shoots can push through and the seed can sprout -- a process that sometimes takes up to six months.
Stems and Rhizomes
Seedlings grow slowly, and plants typically become established only after three to six years. Saw palmetto’s growth cycle is slowed even more if the seedlings grow in water-saturated soil that drains poorly, such as in floodplains or during rainy seasons. Because the stems grow only 0.04 to 0.1 inch per year, age estimates of some mature plants are reported to be 500 to 700 years. Saw palmetto also spreads by rhizomes, which are modified stems that grow laterally just above or below the soil line. The rhizomes produce roots below and shoots above their lengths, forming new plants.
Saw palmetto’s benefits to wildlife are many. It provides habitat, food and protection to birds, butterflies, reptiles and mammals. However, the same razor-sharp spines that line its petioles, protecting wildlife that seek refuge underneath the plants, are hazards for children. If you grow saw palmetto, proper placement in your garden may minimize the cutting risks to unsuspecting little fingers. Plant it away from play areas and walkways. Also, locate the plants away from grilling areas because the foliage is flammable.