“I love that monster, even though it keeps us from living anormal life.” So writes Al Kray about his bearing avocado tree inGlendale, California. Other home growers might agree: when an avaocadotree rewards you with a hefty crop, it’s easy to overlook thetree’s faults: large size, temperamental bloom habit, constant leafdrop, and a dense, shade-casting canopy that makes for difficultgardening below. If you’re growing an avocado tree now or are planning to plantone, here’s advice on how to keep it happy, how to live with itshabits, and how to harvest the fruit. More than 300 readers contributed to this report; they wrote us inresponse to a query in Sunset.
Some, like Dr. Baldwin Lamson (picturedon opposite page) and the Joe Muellers (above left), started trees asnursery-grown plants; Dr. Lamson now grows 28 trees-eight varieties–ona terraced, 1/2-acre hillside. Many, like john Eells (left), inheritedtheir trees from previous owners. Still others, like Mrs. Roland Manning(above), started trees by sprouting seeds in glasses of water in thekitchen. Mid-March is the best time to plant an avocado tree in mild, nearlyfrost-free climates (see the map on page 121 for areas where avocadosgrow best); the longer the tree has to get established, the better itwill be able to withstand the first winter.
If frost is still possiblein your area this month, your winters are probably too cold foravocados. Start with the right variety The best variety for your climate and site can improve your chancesfor a bearing tree. If in doubt, your extension service. At left, we show seven commonly grown varieties.
If you inheritedyour tree, the photograph can help you identify it. Guatemalan types are the most frost-tender; they’re widelygrown only in the most frost-tree areas, including mildest parts ofSouthern California. Mexican types are hardiest but smaller and thin-skinned.They’re best for lower, colder inland valleys and temperate areasof northern California. ‘Fuerte’, a hybrid midway in hardiness (about like alemon tree), is widely grown in slightly colder ares of inland SouthernCalifornia and in the San Francisco Bay Area. Once popularcommercially, it’s touchy about bearing fruit in areas where earlyflowers are subject to frost.
Where garden space is at a premium, try a dwarf or semidwarfvariety, such as ‘Littlecado’, ‘Gen’, or’Whitsell’. Nurseries sell trees in 5-gallon cans for $14 to $20, in 15-galloncans for $30 to $65. Plant in well-drained soil in full sun, in a spotprotected from wind. Seedlings: a gamble, but you may get lucky If pit-started trees bear at all, their fruit usually differs insize, shape, and quality from the mother plant. Our readers reportvarying degrees of success with them, from excellent (“My pride andjoy is 31 years old and consistently produces tasty, black-skinnedavocados”) to s-so (“I’m not really crazy about thefruit”) to no fruit at all (“After 20 years, my seedlingremains a lush, healthy ornamental”).
If you have space to spare, you might try growing a seedling. Toreduce the gamble, you can graft a bearing avocado onto the seedlingrootstock, but this takes patience and some know-how; only two out ofnine readers who tried it reported success. “If you want to harvest avocado of predictable quality,”writes Frank Ishihara of Alta Loma, “you can’t make a betterinvestment than a nursery plant.” Secrets of success: how to water,fertilize Avocado trees can’t take drought, but they don’t like wetfeet either.
One rule of thumb: water whenever the soil is dry 18 to 22inches below the surface (check at the drip line with a soil auger). Formature trees in well-drained soils, that usually means watering everytwo to four weeks in summer, more often in hot, dry, windy weather.Frequent light waterings are best where soil is shallow, since rootsystems are most likely in the first foot of soil. Deeper watering isbest in deep, sandy loam–the best soil for avocados–where roots can be2 to 3 feet deep. A heavy watering about every fourth time helps flushsalts from the soil. Rotating sprinklers and drip emitters work well.
Most Sunsetreaders prefer slow soaking with a hose around the drip line. Onereader soaks the root zone under his tree one quadrant per weekend(always the same section on the same Saturday of the month) for an houror two, depending on the weather. IF you build a watering basin around the drip line, knock it downbefore rains come to keep water from building up. Mature bearing avocado trees grown by Sunset readers get every kindof feeding regimen: no fertilizing at all, occasional fertilizing, orlight applications as often as once a month during growing season. Nitrogen is the chief nutrient avocado trees need; mature treesappreciate about 1 pound per year. Some gardeners use ammonium sulfate.
A complete fertilizer with an NPK number of about 10-8-6 (sometimes soldas “citrus and avocado food”) is another popular kind; aregimen of 3 to 5 pounds per mature tree applied two times a yearbetween February and October equals about 1 pound of actual nitrogen peryear. Young, nonbearing trees get off to a good start with much less:about 1 teaspoon every second or third watering the first year,following package directions. If pruning is necessary Mature avocado trees need little or no pruning. Left on their own,however, some varieties grow into shapeless mounds of foliage; othersshoot skyward and dangle their crops mostly out of reach. Best time for shaping and developing a good branch structure iswhen a tree is young. To induce bushiness in upright growers, pinch outterminal buds after each growth spurt for the first few years. Once trees are established, most Sunset readers prune them only tokeep stray limbs out of their neighbor’s yard or below telephonewires, to open up the canopy to prevent wind damage, or to lightenexcessively heavy limbs.
If you prune, make cuts as close to a main branch as possible, andremove as little green wod and as few leaves as possible. Before youprune off lower branches to expose the sunburn-prone trunk, make surethe leaf canopy is dense enough to shade it, or coat the trunk withwhite water-base paint. Be consistent about pruning top growth ofupright kinds, or it will grow right back. Avocado trees are relatively trouble-free in home gardens. Forsome problems encountered by Sunset readers–and what to do aboutthem–see page 232.
If you live outside the avocado belt, cover trees the first yearwith burlap (not touching foliage), if necessary, to protect them fromhottest sun and frost. A word about pollination If there are bearing trees in your neighborhood, you probablydon’t need to worry about pollination, and you may get a bettercrop: one reader’s tree bears its heaviest crop on the side facinghis neighbor’s tree, 20 feet away. Weather must be warm (above 60[deg.] or so) when flowers form, orfruit won’t set. For more abut pollination, see page 232.
Whenand how to harvest On the tree, avocados don’t soften until past their prime, soit’s difficult to tell when to pick them. Some readers go by frutappearance: “The skin of ‘Mexicola’ gets a frosty look,and the fruit comes away from the stem easily.” Or by sound:”Shake a ripe ‘Duke’ and the seed inside rattles.”Others wait for local critters to give them a clue: “When I spotraccoons washing avocados in my pool in the dead of night, I knowit’s time to pick.” But there are other clues: as they mature, dark-skinned kinds turnfrom green to dark; green-skinned kinds lose their shine. Stems turnyellowish on some kinds. If you cut an immature avocado in half, theseed coat looks thick and white; in a mature fruit, it’spapery-thin and dark brown. Best way to tell if it’s harvest time is to pick a largeavocado and let it soften indoors.
If the fruit is mature enough topick, it will soften in about 5 to 10 days; if immature, it will shrivel(wait a week and try again). Often the only way you can harvest the upper reaches of a tall treeis with a pole picker (see cover photograph). Sunset readers useeverything from a polemounted 1-pound coffee can with a V cut in the rimto a swimming pool brush pole with a three-prong cultivator attached.(Cutting the stem is better than pulling it; leave a little stem”button” attached.) A few readers report success with theteam “cut-and-catch” method: one person mans the pole picker,while the other catches the avocados in a net bag. You can buy pole pickers with cutting devices attached and longcords for operating them; some come with canvas bags attached to catchthe fruit. Even with a ladder a pole picker, you may have to wait for gravityor squirrels to harvest crops from tallest trees.
Some tree serviceswill pick fruit from very tall trees, but it’s expensive (about $60per hour for a two-person crew). If you grow a summer-bearing variety,some tree services will pick highest avocados and lightly prune or shapethe tree at the same time. (Pruning in late fall and winter stimulatesnew growth that’s most susceptible to frost damage.) Until late in the season, most back-yard growers harvest only whatthey use in a week or so.
Some varieties can stay on the tree up tofive or six months; others need harvesting within two to three months.What to do with leaf drop A few Sunset readers rake fallen leaves into a uniform layerbeneath the tree for mulch; for a neater pile, run over it with a rotarylawn mower, or confine fallen leaves with a low wire fence around thedrip line. You can make compost below the tree: water and turn leavesoccasionally, then rake them up each fall and dig them into garden beds. If piles of leaves invite tree rats in your area, compost theleaves or send them out with the trash. Gardening under avocado trees Some fastidious gardeners prefer to grow things under their avocadotrees.
Bernice Mattern of San Jose (see photograph above) isn’tconcerned about disturbing the shallow roots of her 35-year-old’Fuerte’ when she plants: “I poke around with a shoveluntil I find a place where no big roots are, then I dig.” If you’d rather not risk injuring shallow roots, confineplants to posts clustered around the tree’s base, or to basketshung from the tree’s widest, strongest limbs. Two readers nurture thriving St. Augustine lawns below avocadotrees, lightly pruning their canopies so the grass gets some filteredsun. One reader finds the concrete patio encircling his tree to the dripline makes clean-up easy, but watering and fertilizing tough.
He feedsand waters the tree through 15-inch holes and waters into the soil every30 inches around the patio edges.