#510 Growing Citrus in our Climate
Success with little protection!
Dwarf citrus varieties make excellent container plants for yard or patio. When growing them in a pot bring them to shelter during freezing temperatures. If brought inside, try to avoid keeping them there long or premature blooming may start. They can also be planted in protected areas of the landscape. If exposed to temperatures in the mid to low 20s for longer than a few hours, damage is likely. If plants re-sprout it is possible that the new sprouts may be from the rootstock and so be different plants altogether. Due to the unpredictability of our winters, and the difficulty in protecting large trees, we don’t recommend the planting of full sized citrus trees in the outdoor landscape in this climate.
PLANTING: For container specimens, use an all-purpose potting soil. Make sure the mixture is well moistened before and after planting to avoid dry pockets of soil in the container. Measure the depth of the rootball before potting in order to keep the surface of the roots from being buried. Try to minimize any additional potting soil over the top of the roots that would be needed to compensate for settling. Keep soil uniformly moist during growing season and do not allow the plant to sit in standing water. Empty your drainage saucer!
For landscape plantings, make sure the soil drains properly. See StarNote 001, Planting Guide, for proper hole size, soil amendments and watering. Plants can take full sun but may sunburn if not protected from reflected heat sources like block or rock walls, and metal or stucco buildings. Water plants the day preceding a forecast freeze. Cover with burlap on cold nights or place a box or other container over the plant and secure with a rock or other heavy object. Because daytime temps can get warm, try to remove the cover during the day.
FERTILIZING: Use Dr. Q’s® Citrus Food (14-7-7) in February, May and September. This complete, organic-based fertilizer has all the micronutrients necessary for vigorous growth and heavy production. If yellow leaves with dark green veins appear, treat with a fertilizer supplement like Dr. Q’s Iron Worker® or KeRex® to correct the problem. Remember, supplements do no good if iron chlorosis is due to over-watering.
COMMON CITRUS PROBLEMS: The following problems are frequently encountered when growing citrus in Southern Nevada and Southern Utah:
Cold Damage. Leaves may freeze and fall off, but tree will usually recover if cold is not prolonged or too severe. Don’t prune cold-damaged trees until new growth shows extent of the damage.
Fruit Drop. Trees set much more fruit than they can actually produce, so a certain amount of fruit drop is normal. Most of this occurs when the fruit is the size of a pea. Sudden, dramatic temperature changes, strong winds, lack of pollination as well as improper fertilizing and watering during fruit set can also cause the problem. Be sure to maintain a uniform watering schedule during the fruit set period.
Gummosis. Fungus disease, also called brown rot and foot rot, caused by standing water around the trunk. Can easily be prevented by good drainage and proper watering habits. If tree is infected, remove discolored bark and wood and treat with a Bordeaux (copper sulfate and hydrated lime) mixture.
Sunburn. Trees with insufficient water will develop dry leaves and scalded fruit in extreme summer heat. Trees with south and west exposures may suffer in any event. Site your trees carefully. White-wash exposed trunks with white tree paint.
Pests. Aphids may appear on new growth in early spring. Blotchy or stippled leaves may indicate the presence of mites. Tap the leaves briskly on a sheet of white paper to see if you have these nearly microscopic pests. Control with regular foliage washing or see your Star Nursery sales associate for help with the correct insecticide. White, cottony masses on stems may indicate the presence of scale insects. Scrub off and treat with an insecticide like Spinosad®. Snails can cause damage to fruit; ants compound problems caused by aphids and scales. If present, control with snail & slug bait or Tanglefoot® as needed.
POPULAR CITRUS VARIETIES: These varieties are most commonly grown in our area. Cold hardiness is indicated. Other varieties may appear from time-to-time and may be more or less suited to your use.
CALAMONDIN is a beautiful, cold tolerant ornamental tree with small, sour orange fruit. Grown more for looks than fruit. Great patio tree or clipped hedge. If healthy, hardy to 25 F. Protect at 30 F.
GRAPEFRUIT is more cold hardy than most citrus, if healthy, handling temperatures to 25 degrees with little damage. Both white and red flesh types produce well and keep well on the tree. Red varieties are a little sweeter. Good container choice. If healthy, hardy to 28 F. Protect at 32 F.
Grapefruit Varieties: (White) Marsh, ripens November-June; Oro Blanco is a very sweet variety that ripens December-April. (Red) Rio, ripens May-September; Cocktailhybrid is a seedy, yellow fleshed grapefruit with excellent flavor. Ripens December-March.
KUMQUAT is a heavy producer of small orange fruit that can be eaten peel and all. An excellent container plant, and extremely ornamental, this tree tolerates cold better than any other citrus. If healthy, hardy to 22 F. Protect at 30 F. Nagami is the variety most often found here.
LEMONS are the fastest growing citrus and very easy to grow in containers. Most are frost tender and should be covered or brought inside when temperatures reach 30 degrees. Varieties available here are usually everbearing. If healthy, hardy to 28 F. Protect at 32 F.
Lemon Varieties: Eureka, the standard market lemon. Meyer, an improved genetic dwarf, is best for containers, more cold hardy and sweeter than others. Pink, thick skin, pink flesh, high acid. Ponderosa, novelty type with huge, juicy, thick skin fruit.
LIMES are the most tender of the citrus and usually quite thorny. Difficult to grow in the ground; much better suited to containers. If healthy, hardy to 30 F. Protect at 32 degrees; watch wind chill carefully.
Lime Varieties: Bearss, seedless, juicy, lemon size and color at maturity. Mexican, small, seedy and juicy. Sweet, very juicy, low acid, tender and aromatic.
ORANGES are best suited for container growing in our climate. If healthy, hardy to 32 F. Protect or bring indoors when temperatures are forecast to be 30 degrees or below.
Orange Varieties. Lane Late Navel, seedless, large fruit, ripens February-September. Moro Blood, red flesh, thick skin, excellent flavor, ripens February-May. Pink Navel, pink seedless flesh, large fruit, ripens January-May. Valencia, seedless, thin skin, medium size juice orange ripens April-October. Washington Navel, seedless easy peel, sweet and juicy, most popular, ripens January-May, spotty producer here.
TANGERINES (MANDARINS) can be good producers in desert areas; best in containers. All varieties are heat-loving and tolerate more cold than many other citrus. The term “tangerine” is interchangeable with “mandarin” and not a separate classification. Most varieties are small, easy to peel and have rich, sweet flavor. If healthy, hardy to 28 F. Cover or bring indoors when temperatures fall below 25 degrees.
Mandarin Varieties: Algerian (also known as Freemont), ripens February-May. Dancy, ripens March-April. Honey (also known as Murcott), super sweet, nearly seedless, ripens January-August.
TANGELO is a cross between a tangerine and grapefruit. It has a unique flavor, few seeds and medium to large size fruit. Minneola is the variety most often seen here. Ripens February-April. If healthy, hardy to 28 F. Protect when temperatures fall below 25 degrees.