A feathery palm that rivals the beauty of a coconut palm, the queen palm (Syagrus romanzoffiana) grows with a straight, upright trunk and is known to produce lots of seeded fruits. Native to the monsoonal forests and swamps of southern South America, it is a fast growing and inexpensive palm to grow in mild winter regions. It is best grown in USDA hardiness zones 9 and warmer and can survive minor bouts with light winter frosts and freezes.
As long as temperatures remain above 25 degrees F, the queen palm shows little or no signs of harm. Once temperatures drop to 20 to 25 degrees F, damage is guaranteed; below 15 degrees F, expect plant death. Robert Lee Riffle and Paul Craft, world-renowned palm experts and authors of "An Encyclopedia of Cultivated Palms," note that queen palms (and their seedlings) that are native to the colder regions of South American are more likely to survive winter frosts without damage. Those native to the more tropical areas of southern Brazil may manifest more extensive problems when faced with subfreezing temperatures.
Among the first signs of frost damage is the yellowing and eventually browning of the tips of leaflets on the queen palm fronds. The colder the weather, the more substantial the browning or spotting on fronds. In severe exposure to subfreezing temperatures, all fronds in the canopy can be killed. As long as the growing tip of the palm is not damaged by cold, the plant will produce new fronds. Keep in mind that damage on palm fronds may not reveal itself for several weeks or months, and new frond growth only occurs once temperatures have considerably and consistently warmed in spring.
Response to Frost Damage
Horticulturists with the Nassau County Extension Service in Florida recommend against doing anything to a frost-harmed queen palm during the winter. Retaining the yellowing and/or dead fronds provides some insulating protection to the growing tip at the top of the queen palm's trunk. Cut away only fully dead (brown) fronds in late spring; retain yellow fronds so nutrients can be used by the plant to produce new fronds. Once new fronds are apparent, you know your palm is alive. If no new frond spears appear by midsummer from the growing tip of the queen palm, the palm has been killed and needs full removal.
Frost-damaged fronds will not recover and become fully green and lush once warm weather returns. Any yellow to green parts of the fronds will continue to produce food for the palm and hasten its recovery and production of new fronds. Depending on the number of fronds killed in the queen palm's canopy, it can take upwards of six months to two years for the canopy to be fill once again with perfect, green fronds. You can hasten the production of fronds by ensuring the soil is moist and fertile (fertilized with palm-specific fertilizer granules) during the growing season after the frost. If a drought occurs, the queen palm may slow its regrowth unless it is given special attention.
Unless the queen palm is small, protection of the plant on nights with expected frosts or sub-freezing temperatures is impractical. In fact, seedling queen palms possess less tolerance to cold since there is less biomass and they are closer to the ground where the coldest air pools. Options for protection include carefully wrapping the fronds upwards and insulating them with bubble wrap and sheets or planting your queen palms in the warmest micro-climates in your landscape, such as on the southern side of hills or buildings, out of cold winter winds.