Most palm trees can be only seen in tropical climates. But luckily, there are also palm trees that comfortably grow in subtropical and temperate climates. You will be probably surprised to find out that there are even palm trees that can survive subzero temperatures and snowfalls.
To grow palm trees successfully in cold climates, you need to choose a palm that is cold tolerable enough to withstand winter in your area. Using a microclimate of your property might make a huge difference in the number of palm species you can grow.
Acclimatization and soil conditions can also play a huge role in how fast your palm gets established in the new location. Growing palm in zone 8 should be not a problem if you follow my tips below.
1. Find Your Hardiness Zone
The North America is divided into 11 hardiness zones with each growing zone being 10 F warmer in an average winter than the adjacent zone. The latest version of the USDA Zone Map was jointly developed by Oregon State University’s (OSU) and USDA’s Agricultural Research Service (ARS) in 2012.
If you compare the previous version of the map that was done in 1990, you will see that zone boundaries have shifted in many areas and that the new map is generally one 5F half-zone warmer. To find your zone, go to the USDA site and enter your zip code.
You can also check past winter records in your area to see if you live in a microclimate. Microclimate a small area that has a slightly different climate from a general climate of a region. Knowing your hardiness zone, will help you narrow down your palm tree selection.
2. Select The Right Palm Tree
Not all palm trees can tolerate cold temperatures the same way. Since palm trees have originated from different countries, they have different cold tolerance called “cold hardiness”. The best way to determine the lowest temperatures and humidity levels that palm can tolerate is by looking at its natural habitat.
Millions of years in the same environment, have let palm trees to adjust to the reoccurring weather conditions making some palms more cold hardy than others. That being said, palm trees native to the Mediterranean region are more cold hardy than palms that are native to warmer climates such as Fiji.
When choosing a palm tree for your climate, make sure to check its cold hardiness. Check out my post about 20 cold hardy palms that can survive the snow and freezing temperatures. While most of them can be grown in zone 8, there are some very cold tolerant palms that can even survive in zone 7.
The difference between cold hardy palms and warmth loving palms is quite significant. For example, Coconut palm can tolerate cold down to 40F while Needle Palm, which is the hardiest palm tree in the world, can tolerate cold down to -5F and is known to survive -24F.
3. Use Microclimate Of Your Property To Your Advantage
Every yard has microclimates where the temperatures are one-hafl to a full zone warmer (or colder) than the rest of your area. In most gardens, drainage, soil conditions, light levels, and other features vary, often over only a few feet of space. To use it to your advantage, grid out your property in terms of microclimate areas.
Look for sheltered from the wind places, the compass orientation of your house, lowest and highest elevation, tall evergreen shrubs and trees, full-sun and shady areas, water features (if any) and etc. The easiest way to find warm microclimates is by absorbing frost coverage.
To get more precise data, place inexpensive thermometers, that you can get at any hardware sore, all over the yard. They should be about 1-2 ft above the ground. You will notice temperature variations over a cold winter night. In the cold climates, the microclimate can make a huge difference allowing you to grow grow 400 species of palms vs 50 species.
You can protect palm tree from chill of cold winter winds by planting it behind a dense shrubs, windbreak or a sheltered courtyard. Other warmer spots will be near a building, fences, paved surfaces, overhanging porch, water feature, under a canopy of a taller tree or on a hill side.
Additionally, palms will stay warmer near a stone or brick wall, or any other structures that absorbs heal all day along and releases it at night keeping palms warm.
4. Acclimate Your Palm Tree
Because palm trees are becoming more and more popular, many palm tree nurseries grow thousands of palms trying to keep up with the demand. Usually, all species are grown in the same location.
Since most of the nurseries are located in the warm climates, those palm trees will hardly ever see temperatures below freezing. If you buy one of the cold hardy palms that have never experienced cold weather and plant it in the colder climate, it will not survive.
Cold hardy palms need to be acclimated so they can better tolerate cold weather. Acclimation, also known as acclimatization, should be done slowly to avoid a state of shock.
While some nurseries will acclimate cold hardy palms before selling it to the customers from northern regions, others just don’t have time. This is another reason to buy palms from well known and trusted palm nurseries that care about quality of their trees instead of just trying to make money.
To acclimate palm tree to cold, you need to gradually expose it to cold temperatures while still providing freeze protection. There are a lot of different winterization techniques. I recommend starting with the basic ones.
5. Provide Enough Time For Root Development
Mature palm trees have more chances of surviving a cold weather because their trunk is thicker, they have more leaves to protect the most important part of the tree, which is the bud, and their root system is more extensive.
Some cold hardy palms even develop a husk, an outer layer of fiber that protects their trunk from cold. Young palms with thinner bark and smaller root system just not strong enough to recover from cold weather.
Another thing to keep in mind, if you transplant a mature palm to a new location and don’t give it enough time to develop enough roots before the cold weather, it might not survive. That is why I recommend planting palms in the spring. That way, they will have enough time to develop the root system.
6. Provide Great Soil
Although many palm trees can adapt to different soil types, most of them do best in well-drained organically rich soils. Some palm trees will also do great in clay soil as long as some organic matter has been added and drainage is good. An added benefit of the clay soil is that it acts similar to pavement, trapping heat and moderating temperatures.
To determine what kind of soil you have, you can send a soil sample for a test to one of the soil testing companies or you can just do a ball test. Dig up some soil and try to make a ball.
The perfect soil will make a crumbly ball because it will have different sizes of particles with some of them from sand, some from clay and others from organic matter. If your soil is primarily made out of clay, you will get a gooey mass. The sandy soil will not make a ball at all.
Clay soils are great at retaining water but have slow drainage and prevent oxygen from penetration to the root zone. Sandy soil is also a problem, because it drains too well letting the nutrients leach away after each rain.
To improve sandy or clay soils, add a lot of organic matter like peat moss and organic humus. For those of you who don’t know, humus is essentially a dark, organic, mostly carbon-based spongy material can no longer be broken down. You can easily find those at your local gardening store. This should provide soil with nutrients and promote water retention and drainage.
7. Improve The Drainage
Check the drainage by digging out a 12 inch hole and filling it with water. After it drains, refill it 10 hours later and see how long it will take to drain. In well-draining soil the water should go away in about 2 hours. If it doesn’t, consider improving the drainage before planting. Otherwise, standing water will cause a root rot and your palm will die.
You can improve the drainage by: adding construction sand and organic material to the soil, adding rocks to the bottom of the hole, drilling the holes in the bottom to loosen up the soil.
The most involved is probably installing a pipe that will take water away from the plant. That will require a lot of digging.
8. Fertilize Your Palm Tree
Another important factor in the successful palm growth is its health. The healthier the palm the more chances it will survive cold winter temperatures. Since palm trees go through multiple phases of acclimation and de-acclimation throughout the year, providing them with enough nutrients during warm months is the key.
I always recommend using a good quality slow release fertilizer and not a cheap one that will be washed away after a few rain falls. This will give palms enough time during warm months to absorb all the nutrients and prepare for the winter.
Research showed that mid-winter fertilization has no effect on the palm survival rate. As it gets colder, palms start to enter a hibernation phase where their photosynthesis process slows down and lesser nutrients are absorbed.
9. Improve Water Intake
One of the biggest problems for palms while they are establishing is a drought stress. Drought stress can weaken the palm and affect its ability to withstand cold. Aside from deep watering technique that is widely used, there is another little trick you can do.
Install a 4-inch plastic drain pipe right next to the root ball when planting a palm. Drain pipe is round pipes with holes that is used for waterproofing a basement. It collects water through the holes and send it to the sump pump.
The pipe should be slightly higher than the mulch at the top and go all the way to the bottom of the planting hole. This way you can get water right to the root of the palm!
This is a great solution for watering palms during cold winter when frozen soil makes watering impossible. You can use warm water to provide even more warmth to the roots of the palm. Make sure to use a cap at the top so that winter air doesn’t get to the roots and to prevent moister loss during hot summer days.
10. Palm Cold Protection
Palm tree cold protection can play an important role especially for the newly planted palms. It takes palm three full growing seasons to become fully established. In heavy clay soil it might take even longer. While your palm is getting used to the new environment, it’s extremely sensitive to cold, drought or any other stress.
So I highly recommend using cold protection in the first three years of palm’s establishment and for sudden cold snaps after. There are a lot of different techniques that you can use to protect your palm, but here are some easiest ones:
Mulching. The easiest thing is to apply 6-12 inches of mulch. This will protect the roots and the bottom of the trunk from freezing.
Christmas lights. Another simple thing is to put Christmas lights around the trunk of the tree. This will add a festive look and about 2-3F during cold winter night. Keep in mind, if there is a wind, all the heat will disappear.
Antidesiccant spay. Water loss from the foliage if one of the biggest problems during cold winter days, especially if the freezing temperatures are accompanied by bright sunshine and chilly winds. Antidesiccant spay can help! This spray creates a waxy layer that prevents a water loss from the tree’s foliage.
Heavy watering. Water heavily the soil around the palm prior to a cold snap. This will warm up the roots since moist soil loses heat less rapidly than dry soil. Using lukewarm water instead of a cold one will warm up the roots even more.
Mummy wrapping. This one will require a little more effort. Using a synthetic blanket that does not trap moister, wrap the the trunk and as much foliage as you can without braking it. Secure it with duck tape. You could add Christmas lights around to provide even more warmth.
Remember, a little bit of cold weather is good for the palms. It makes them more cold hardy. So don’t start wrapping them up at the first sign of winter.
Without any tips above, you can easily grow cold hardy palms in zone 8. By using a microclimate of your property and some cold protection techniques you even push it one zone up. That means if you live in zone 7, now you can grow palms that are only hardy to zone 8.
- Palm Tree Cold Protection
- How to Save Cold Damaged Palm Tree
- Importance of Microclimate When Choosing Cold Hardy Palms
- Top 10 Cold Hardy Palm Trees