Zone 7 Citrus Trees: Tips On Growing Citrus Trees In Zone 7
The aroma of citrus fruit is evocative of sunshine and warm temperatures, exactly what citrus trees thrive in. Many of us would love to grow our own citrus but, unfortunately, don’t reside in the sunny state of Florida. The good news is that there are several hardy citrus tree varieties – being citrus trees suitable for zone 7 or even colder. Keep reading to find all out about growing citrus trees in zone 7.
About Growing Citrus Trees in Zone 7
Temperatures in USDA zone 7 may dip down as low as 10 to 0 degrees F. (-12 to -18 C.). Citrus doesn’t tolerate such temperatures, even the most hardy citrus tree varieties. That said, there are a number of things you can do to protect citrus trees grown in zone 7.
First off, never plant citrus in an area where it will be assaulted by cold northern winds. It’s important to select a planting site that not only gets plenty of sun and has excellent drainage, but one that will provide some cold protection. Trees planted on the south or east side of a home will get maximum protection from winds as well as radiated heat from the house. Ponds and other bodies of water or overhanging trees will also help trap heat.
Young trees are most susceptible to cold temps, so it might be advisable for the first few years to grow the tree in a container. Be sure that the container drains well since citrus doesn’t like wet “feet” and put it on wheels so the tree can be easily moved to a more sheltered area.
A good layer of mulch around the base of the tree will help to keep the roots from getting any freezing damage. Trees can also be wrapped when chilly temperatures are looming to give them even more protection. Cover the tree completely with two layers – first wrap the tree with a blanket and then plastic. Unwrap the tree the next day as temps warm and pull mulch away from the base of the tree to allow it to absorb heat.
Once the citrus tree is 2-3 year old, it can tolerate lower temperatures better and recover from freezes with little to no damage more easily than young trees.
Cold Hardy Citrus Trees
There are both sweet and acid types of citrus trees suited for zone 7 provided there is adequate protection from cold temperatures. Selecting the proper rootstock is crucial. Look for trifoliate orange (Poncirus trifoliata) rootstock. Trifoliate orange is the superior choice for cold hardiness but sour orange, Cleopatra mandarin and orange crosses may be used.
Mandarin oranges include the mandarins, satsumas, tangerines and tangerine hybrids. They are all sweet types of citrus that peel easily. Unlike other zone 7 sweet citrus trees, mandarins need to be cross-pollinated for fruit set.
- Satsumas are one of the most cold hardy of the citrus and differ from mandarin in that it is self-fruitful. Owari is a popular cultivar, as is Silverhill. They fruit well ahead of any potential freezes (normally fall season) and have a relatively long shelf life of about two weeks.
- Tangerines are the next best bet with regards to cold hardiness. Dancy and Ponkan tangerines are self-fruitful but another cultivar, Clementine, requires cross-pollination from another tangerine or tangerine hybrid. Tangerine hybrids such as Orlando, Lee, Robinson, Osceola, Nova and Page are preferable over Ponkan or Dancy, which ripen later in the season and are susceptible to colder temps.
Sweet oranges should only be attempted along lower coastal areas of zone 7 combined with adequate cold protection. Hamlin is a great choice for those that wish to grow oranges for juice. It has the greatest cold hardiness of the sweet oranges, although it will be damaged at temps down to 20 degrees F. (-7 C.) or lower. Ambersweet is another sweet orange variety to try.
Navel oranges can also be grown with adequate protection from cold. Although they are not as fruitful as sweet oranges, they ripen fairly early from late fall through early winter. Washington, Dream and Summerfield are types of navel oranges that can be grown in the more temperate coastal regions of zone 7.
If grapefruit is your favorite citrus, realize that it lacks much cold hardiness and it can take 10 years or more for a seedling to produce fruit. If that information doesn’t deter you, try growing Marsh for white seedless grapefruits or Redblush, Star Ruby or Ruby for red seedless. Royal and Triumph are delicious white seed varieties.
Tangelos might be a better bet for grapefruit lovers. These hybrids of tangerine and grapefruit are more cold hardy and have fruit that ripens early. Orlando is a recommended cultivar. Also, Citrumelo, a hybrid between trifoliate orange and grapefruit, grows rapidly and produces fruit that tastes like grapefruit, and may be grown in zone 7 with adequate protection.
Kumquats are the most cold hardy of the acidic citrus. They can tolerate temperatures down to 15-17 F. (-9 to -8 C.). The three most commonly propagated are Nagami, Marumi and Meiwa.
Calamondins are small, round fruits that look similar to a tangerine but with very acidic pulp. The fruit is sometimes used as a substitute for lime and lemons. They are cold hardy down to the low 20’s.
The Meyer lemon is the most cold hardy of the lemons, producing large, almost seedless fruit that ripens over the course of several months, beginning in late summer. It is cold tolerant to the mid-20’s.
Limes are not particularly cold hardy, but the Eustis limequat, a lime-kumquat hybrid, is hardy into the low 20’s. Limequats make great lime substitutes. Two cultivars to try are Lakeland and Tavares.
If you want to grow citrus for its visual appeal more than its fruit, try growing the above mentioned trifoliate orange (Poncirus) that is most often used as rootstock. This citrus is hardy in USDA zone 7, which is why it is used as rootstock. The fruit, however, is hard as a rock and bitter.
Lastly, a popular citrus that is extremely cold hardy is the Yuzu. This fruit is popular in Asian cuisine, but the fruit is not actually eaten. Instead, the flavorful rind is used to enhance the flavor of many dishes.
Protecting In-ground Citrus & Avocados - Zones 7, 8 and 9b
With the onset of winter comes the cold. Depending on where you live you may have begun watching the weather reports to get ahead of a cold snap that could damage your Citrus or Avocado plants.
Depending on the variety, a rule of thumb is Citrus and hardier Mexican varieties of Avocados will tolerate to 30 degrees Fahrenheit for about 3 hours without damage. Some noted exceptions would be the Mexican Lime and any citrus or Avocado tree that has been recently planted.
Selecting the best location to plant is your best advantage against the cold. Choose locations that have good air movement but not exposed to high winds and avoid low locations where cold collects during the fall and Winter. In marginal citrus locations (zone 7) selecting a wall of the house or a south facing wall that radiates heat to add protect to your plants. Avocados are not recommended for planting in the ground in Zone 7.
Protection for you citrus should begin in the late summer. A good feeding with and organic fertilizer in September will help add to the protection against winter frost. The current rule is a well fed and well-watered citrus will improve the plants tolerance to cold. Also with Zone 7 Citrus, colder weather may call for wrapping the trunk into the lower canopy with burlap or old blankets and then mulching the base of the tree to 4 inches out past the canopy adds to the overall protection
In all zones prone to freezes a frost blanket to cover the tree is essential. Adding 100 watt conventional bulb or a string or 2 of C9 Christmas lights hung through the trees under the Cover will add to the degrees of captured heat. I have found that during the cold periods leaving the covers on for a few weeks will not bother the tree. Be sure to turn the lights on early in the evening to allow the heat to collect under the cover. There is some evidence that pulling back the mulch during the warm part if the day allows the ground to heat up to be released into the canopy later that evening.
The real trick to successful Citrus and Avocado Protection is keeping the trees below 10 feet during the growing season. I recommend below 8 feet to make covering and adding protection like lights a breeze. When size control is a part of your Citrus and Avocado growing adding a simple structure around your tree is easy and makes applying a frost blanket simple.
Applications of any of the Anti-transparent products are not recommended. Any damage that might occur on the trees as a result of winter cold should be left until the temperatures begin to stabilize in the spring to be pruned off.
Finally, selection of varieties can mean the difference between success and failure. Very few avocados that are not of the Mexican type will survive in a winter cold climate such as Zone 8 or 9b or lower.
Varieties like the Mexicola, Fuerte, Stewart, Jim Bacon, and Zutano are good to try. The all popular commercial Hass should be reserved for Zone 9a and greater.
For the hardest of the citrus, the varieties that are able to tolerate to 28 degrees for short periods are the Meyer Lemon the hardiest of the lemons, Kumquats with Nagami being the most well-known and the Fukushu a newer very sweet large fruited tree gaining in popularity. Calamondins are a very cold hardy kumquat like fruit used mostly in cooking. Owari Satsurma mandarin is a noted cold hardy variety and are very dependable. The jury is still out on newer varieties like Gold Nugget and Pixie. The Yuzu a fruit used primarily for Asian cooking is thought to be the hardiest of all the citrus. Sweet Oranges must be protected along with most Lemons, Limes and Grapefruit. Some varieties to try in these zones are the Trovita Orange, Lisbon Lemon, Bears or Persian Lime and the Oro Blanco Grapefruit.
For all other varieties grown in Zone 9a, 10 or higher, simple recommendations for covering your plants and feeding and keeping them watered in the event of a hard freeze are the order.