Banana

Frost Tolerance: Leaves are damaged at 32°F (0°C), plant will grow back from the root (corm)

Sun Exposure: Full sun to light shade depending on the variety

Origin: Southeast Asia, Australia

Growth Habits: Perennial from 3 to 8 feet depending on variety

Flowers: White or yellow flowers

Watering Needs: Abundant water

Propagation: Offsets

Bananas, some bearing fruit, can be seen thriving in home landscapes scattered in and around the Salt River Basin. These are usually of an unknown variety but, for the purpose of this discussion, their existence proves that many of the hundreds of known cultivars will do at least as well as those already growing and fruiting here. With that knowledge, homeowners should be encouraged to raise them.

Fruiting Habits:
Bananas frequently bloom in Phoenix but fruit is often stunted and bland. That could be a function of genetics but is more likely caused by a nutrient deficiency and lack of water. Tasty fruit can be produced here. Quality may also suffer when the flowering stem is engulfed in a dense banana grove or in close proximity to other hungry, thirsty vegetation. Fruiting exacts a huge energy toll from the mother plant that needs a lot of nitrogen and moisture to sustain it. After a stalk of bananas has developed, it may be 6 to 7 months before the fingers are mature. During that time, if the stalk is exposed to direct mid-summer sun, the fruit may turn black without artificial shade. Drape the entire stalk with any reflective material or brown or white paper. Sever the stalk when ribs have practically disappeared and the fingers have the appearance of a supermarket banana. Hang it in a dark, sheltered spot to ripen. Or, leave the stalk protected on the plant and pick a "hand" at a time as needed and treat them like any other banana. In nature, there is no such thing as a "banana plant". The stem emerges from a corm that continually enlarges and sends up new shoots. With any food and water at all, there will always be a "herd" ranging in size from big ones to tiny suckers popping through the surface. To get the best and most fruit, especially under less than ideal conditions, keep the population of any group to three. One adult that will be chopped down after the stalk of bananas is harvested, one juvenile and a baby are all you need. Remove all other growth as soon as it emerges. Further, as soon as the hands fail to set, lop off the flower head. Bananas are believed to flower only after a certain number of leaves have been produced; Estimates run from 15 to 20’. Count them with a permanent marker if you really wish to know.

Culture:
Bananas grow rapidly in full Arizona sun but if planted in early summer, give the juvenile plant some protection from the hottest part of the day until the root system is sufficient to replace moisture lost from transpiration through leaves. Keep in mind, however, that the plant must have the most light it can tolerate to manufacture food stored in the corm, a storehouse for energy needed to produce the fruit. Their favorite location is a southern exposure sheltered from the wind if possible. A single banana stem has a short life producing a stalk of bananas in about 18 months in ideal soil and climate. With less than a perfect environment, you may wait for 2 years or longer to sink your teeth into a ripe banana grown on your own tree. One plant, however, can develop into a grove in two or three years and may need restraining.

Bananas are not a tree but an herb. They need well-drained soil and frequent water while exposed to hot desert sun. When growth virtually shuts down below 55 degrees Fahrenheit, very little moisture is required to sustain them. Before planting, test your soil’s ability to drain properly. Dig a post-hole about 2 feet deep. Fill it with water. If it empties within two hours, the drainage should be ideal. If you continue to refill the hole, however, you will eventually reach a point when the water will stay for a long, long time. If you water the banana that way after it has been put in the ground, the roots can't get air and rot will set in. Learn to adjust the irrigation frequency to the rate at which the water permeates through and out of the root zone. Winter is the banana's most crucial period. Extended wet-feet, however, will kill them at any time of the year. When actively growing, this herb is very thirsty. Just don't drown it.

Plant your banana in well-drained soil rich in humus. Some banana experts claim an old compost pit would be the perfect spot. Bananas can be foliar fed with a balanced, soluble fertilizer such as 10-10-10 weekly or 20-20-20 every two weeks. Apply a by drenching the leaves on both sides during a cool part of the day. Fertilizing these herbs throughout the year only what they require only when actively growing is better than sporadic, heavy feeding quickly leached away. Apply fertilizer through the soil on non-fruiting young plant groups when temperatures are above 55 degrees Fahrenheit with 1/4th cup of ammonium sulfate every two weeks. Use ammonium sulfate at the rate of 1/4th cup weekly on fruiting plants. Blend the dry fertilizer into damp soil in a shallow trench at least 18 inches from the clump and water it in until a probe can be easily inserted 18 inches into the ground. Irrigate only after the soil is dry an inch beneath the surface and only slightly damp below that. During winter when ambient temperatures are below 55 degrees F, growth is very slow and moisture requirements are low. Irrigate sparingly or not at all if soil is damp. Never add fertilizer to cold, wet soil.

The average mild Phoenix frost will almost never kill the corm and roots but the tender leaves will usually freeze unless they can be covered or otherwise protected. Plug in an air fan and blow air directly on the leaves. Use the biggest one you can find. Wrap the stem with old jackets or a blanket and drape Christmas tree lights on the leaves. Put a flood light or other heat lamps underneath. The shock suffered from losing its leaves will set development back several months and the energy spent saving them is well worth the effort.

In summary, grow well-established bananas in full sun in well-drained soil rich in organic material. Water and feed them well during warm weather, let the plants rest during the winter and be patient.

Propagation:
To harvest suckers or juvenile plants, sever them vertically straight up and down all the way around the stem with a sharp, narrow shovel 12 to 15 inches deep. Worry the base out inflicting as little trauma as possible. Let the wounds harden off several days in full shade. Plant at the same depth and keep the soil on the dry side until there is active growth.

These notes were compiled by Dick Gross for the Arizona Chapter of the California Rare Fruit Growers, Inc. for use at the Garden Festival, 4/10/99 at the University of Arizona Maricopa County Cooperative Extension.

Links:
CRFG Banana Fruit Facts