Native to tropical Southeast Asia, the pygmy palm (Phoenix roebelenii) will suffer damage if winter temperatures drop too low. While prevention is always best, winter lows can catch the best gardener off guard. After a cold snap, the right care is critical or you can cause further stress to the already stressed palm. The pygmy palm has a single trunk and grows 6 to 12 feet tall with delicate green fronds. This dwarf date palm grows in U.S. Department of Agriculture plant hardiness zones 10a through 11.
Pygmy palm trees can tolerate temperatures below freezing but might suffer some damage. In USDA zones 10a through 11, where temperatures remain at or above 30 degrees Fahrenheit through the winter, this palm is fully hardy and will grow well through the winter. This palm can survive temperatures down to 20 degrees, but you might see some frost damage. In areas where winter lows pose a potential risk, plant pygmy palms in a protected south-facing area.
After a cold spell it is important to wait before you start trimming and pruning. Don't prune out dead fronds until the spring. When you prune, only remove fronds that are completely brown, leaving any fronds that only have brown tips. Though the browning foliage is unsightly, the pygmy palm is still absorbing light through the damaged leaves. Removing the damaged frond will cause additional stress and slow the regeneration process.
Fertilizing through the growing season will help improve a pygmy palm's ability to tolerate cold winter temperatures. Use a palm tree fertilizer, like an 8-4-8 formula, every four to six weeks from spring through fall. Use 1/2 tablespoon for each square foot of area extending the fertilizer from the base of the trunk out to the area under the outermost fronds. Water on the morning before a potential frost to keep the tree well hydrated and minimize frost damage. For additional cold protection, wrap a sheet or blanket around the top of the trunk and the base of the fronds
Indoors, you can control the growing temperatures. Ideally, you should keep your pygmy palm in an area where daytime temperatures are no higher than 80 to 85 degrees with a drop at night to 60 or 65 degrees. Place container-grown pygmy palms in bright light but out of direct sunlight. Use a container that has at least one hole in the bottom for drainage and a loamy, well draining planting mix. You can put a saucer under the pot to protect indoor surfaces as long as you empty it when water builds up.