From the 1986 Journal of the California Rare Fruit Growers

MANGO GROWING IN

CALIFORNIA

Jim Neitzel

San Diego, California 92114

 

It has been said that many more mangos are eaten yearly on this planet than apples. Some people in tropical highlands are trying to grow low-chill-requiring apples such as 'Emilia,' 'Anna,' and 'Dorsett Golden' while, conversely, we in Southern California thrill at the prospect of growing the exotic mango.

A Few Mango-Growing Efforts

Different individuals have experimented with mango growing in the more clement California coastal areas for several years now. The first outstanding effort was that of Colonel Bucklew, who planted and eliminated many trees some 30 miles north of San Diego. Finally, a few selections were deemed satisfactory for the cool coastal location: 'Earligold' and 'Cooper,' I believe. Other seedlings of promise have been located in the yards of different individuals scattered up and down the Southern coastal strip. Moreover certain seedlings have been reported to be performing quite well farther inland where it's possible to find sheltered frost-free microclimates that can afford the tree much more heat during the growing period.

The next large-scale effort that comes to mind is that of CRFG co-founder, Paul Thomson. When Paul purchased the five or so acres in Vista at the end of Edgehill Street, he found a hardy and productive mango tree already there and surviving quite nicely. This 'Edgehill' tree must be the largest and oldest mango specimen in Southern California. Although Paul has made other selections with superior fruit, the 'Edgehill' seems to be well adapted to our generally marginal growing conditions.

Seedling selections of the parent tree have been chosen which look very promising. Paul's 'T-1' has a very tasty fruit, and his 'Thomson' variety looks to be an excellent selection. My young grafted 'Thomson' specimen is blooming and setting little fruits like clusters of grapes without any of the mildewing which is so common due to our humid, overcast May and June weather. All fruit should be removed until a tree has achieved some size, but it's a temptation to leave just one.

In addition to seedling trees, Paul sought scions of outstanding cultivars from places as far away as India and Thailand. The performance of only a few of these has been deemed to be satisfactory. Of the Florida selections that Paul has tried, 20222 has proven to bear the finest fruit. Various CRFG members now have grafted trees that do well, but they find that it bears quite alternately. Crafton Cliff of RFCI in Miami visited the Edgehill property this June. He was very impressed with the grove's appearance and production, commenting that these trees looked even healthier than the trees growing in Florida and were laden with fruit hanging down to the ground. The next largest long-term mango growing endeavor locally is that of Jerry Staedeli. Living about three miles from the bay in the south central part of the city of San Diego, Jerry's backyard is filled with mango trees of all sizes. Staedeli's first exciting find was his Aloha,' a large tree grown from the seed of a good Hawaiian fruit eaten there while on vacation. It bears somewhat inconsistently, but it has produced crops of large and beautiful fruits of good quality. His Surprise' and Reliable' selections bear well but don't have quite as good quality. Soft nose can be problematical with some of these selections. His Reliable' trees stay very low and somewhat dwarfish because they bear so heavily and consistently.

A few years back, Staedeli acquired scions of various cultivars popular in Hawaii. Some have been eliminated, but quite a few are showing promise. Jerry will be able to write an update of these and the rest of his plantings in a few years.

Lastly, individual seedling trees have been reported or discovered in somebody's yard in various cities, throughout Southern California. About 35 miles north of San Diego and very near the coast, someone located a seedling bearing lots of fine elongated fruits. Named 'Villasenor' after its owner, its grafts have proved very worthwhile. Member Peggy Winter planted a seedling next to her house on the southern side seven or eight years ago. It has given quite good crops of very sweet, roundish fruits that have impressed all who have tried them. Since the cultivar '20222' has been assigned the name Winters', Peggy has decided to rename hers 'Ultimate.' Ruby Law, another active ~RFG member living near Cucamonga, some 30 miles east of Los Angeles, has grown and fruited three or four seedlings that perform well for her in large containers. Some are very productive but lack taste. One seedling, however, produces large, showy, ruby-red fruits of excellent quality.

The writer, himself, has had container-grown seedlings produce a few fruits. The young 'Haden' and 'Keitt grafted trees have set some fruit already. 'Haden' grafts have fruited for Leo Manuel in Clairemont, but local selections have done best for him. The Pacific Tree Farm Nursery in Chula Vista has fruited the 'Keitt' and 'Edgehill' cultivars in containers, also.

Mangos from Florida

A new twist has been given to the California mango growing picture recently through the initiative of member and nurseryman Bill Nelson. While attending horticultural meetings in Florida, Bill found some nurseries growing certified container-grafted stock which could be shipped to California. He ordered 'Haden,' 'Keitt,' 'Kent,' 'Tommy Atkins,' 'Irwin,' Palmer,' and others. Three or four other nurseries selling rare fruits soon followed suit.

The first three of the aforementioned cuttivars produce such big and tasty beauties, that many CRFG members have jumped at the chance to purchase one or more of these famous varieties. This enthusiasm has been evident in spite of the warnings or doubts expressed by Paul Thomson. One can hope that some of these marvelous cultivars will perform well in some of our varied microclimates. As mentioned, some success has already been reported with two of the best, Keitt' and 'Haden.' Moreover, a large planting of these commercial varieties has gone in recently in the hot Coachella desert valley near lndio. Reportedly the young trees are growing much faster there, and some have been fruiting. If no mean freeze strikes the area before the trees gain some size, California may prove to be a significant producer for wintertime sales.

Future Directions

Meanwhile, one should seek to gain insight into the genetic variables, climatic factors, soil and disease considerations, and other reasons why certain types of mangos thrive in Hawaii or India or Florida or California, but quite possibly not in another mango-growing area. To begin with, it seems at, historically, two basic types of mango have been cultivated. Rulers in India reportedly had huge mango plantings. Since the Indian type are largely monoembryonic, the seedlings would be the result of two parents and, consequently, vary widely. Selection through hundreds of years (maybe even thousands) would logically have resulted in many fantastic cultivars. The Indian-type mango usually has a lot of color and they would more likely satisfy the average customer's bias for showy fruit as the primary consideration of purchase. After observing several young trees, I have developed the hypothesis that the plants having very colorful new growth are probably more Indian genetically and seem much more susceptible to mildew. Since May and June are customarily humid and overcast months along our southern coastal strip, the first bloom is usually for naught. The last few years have been warm enough to get some first-bloom crops, however. Hot interior areas that are relatively free of frost might make it possible for some of these fine Indian types to manage to prosper here. Our climate seems to be warming up some, but one hard freeze could prove fatal, especially to young trees. The Indochinese strain of mangos tends to be less colorful and the seeds are often polyembryonic. Somewhat like nucellar citrus seedlings, many of the two to five or so seedlings that grow from the different sections of the kernel will be genetically identical to the mother tree.

Some cultivated varieties in the Philippines and Asia are propagated merely by planting seeds. This general type often has more resistance to mildew and anthracnose, so obtaining batches of seed of leading polyembryonic varieties to pot up and sell at our plant sales would seem wise. The purchasers could register and maintain an ongoing fact sheet, thus reporting results periodically to the organization.

I have eaten big, long yellow mangos in Mexico referred to as "mango de Manila." They were excellent fruits, with a long flat polyembryonic seed. This label, however, is very inexact because Mexicans use it for many of the smaller earlier fruits also. Some of the latter appear to make good early seed for rootstocks. Often very tasty, these small fruits may be one-third to one-half pit. Apparently, little study of rootstock selections has been done. Vigorous local varieties might be a good way to begin, especially polyembryonic selections.

Since we have high heat only from July to October here, one needs rootstocks and fruiting cultivars that have various good growth spurts, even without too much heat. A good feeding and watering program during the warmer months of summer and fall should also help the trees to take advantage of our shorter period of active growth. Florida may have poorer soil and more freezes in many areas, but usually in between the cold snaps the heat is up.

Growers having a little extra room could plant out rows of seedlings from choice fruits three to four feet apart similarly to intensive pear and apple plantings in parts of Europe. One should note that in Israel mangos are being raised this way on short espaliered trees less than two meters apart. One could similarly make room for several experimental seedlings thus.

Propagation

Planting avocado pits has entertained many plant aficionados. Unless planted upside down, a decorative young plant soon results. Similarly the mango kernel or bean-like seed should be removed carefully from the husk (the 'hairy' edge separates) while avoiding damage to the emerging root or hypocotyl. Plant the concave side down and the hump up, barely exposed. The root thus goes straight down and the plantlet sprouts up between the two cotyledons without having to twist around or becoming trapped. Planting in deep sleeves or directly in place permits a stronger tap root development.

Whip and Tongue

 

To graft, wait until warmer weather begins and growth initiation signals increasing cambial action. Seek scionwood tips that are just about ready to burst into growth. Locally, people tend to use the simple whip graft, the cleft or off-center cleft grafts, carefully matching the two widths. One wraps grafts tightly with plastic tape, then envelops it with a plastic bag having some drops of moisture within, and finally covers it with a lunch bag in which some vent holes have been cut. This shades the graft. Painting a graft with a coat of anti-transpirant such as 'Tree Doe' can replace bagging.

I have noticed that the veneer graft was used on all the trees from Florida. This graft works well if the rootstoek has more size, and it allows the top to stay on longer to push the tree until the two cambium layers unite. Then the top is cut off to redirect all growth into the scion piece. The side-veneer graft gives a great deal more cambial contact.

Crafton Cliff states that the veneer graft is practically the only type he uses except for very young seedlings of avocados and certain tip graftings where he may use a cleft graft of sorts. The veneer graft resembles a very long chip bud. A strip removing about a third of the wood on one side of a 3"-5" scion is cut the entire length except for the very tip, perhaps. A similar strip about 1/2" shorter is cut away on the side of a smooth section of the seedling where the diameter or girth is of similar size. If the girth is larger, one can merely make a more shallow cut-away piece so that the cuts match. This flexibility of scion size is a great benefit. Then a 1/2" downward cut is added at the base of the cut-away area on the rootstock. Next a 1/2" angled cut removing the lower outside tip of the scion piece, making for a short cleft-like insertion at the base. One can thus wrap the entire scion length or wrap it with rubber grafting strips and wax or paint the graft over with Tree Doe' sealant. When the scion buds begin to emerge, the top of the rootstock tree is cut off and scion growth is staked to grow upright.

A third graft I have had excellent results with for top-working large, established trees is a type of crown grafting that I have termed the bark-inlay method. All but one substantial "nursing" limb can be sawed off, preferably in early spring. When a few small buds start to swell the cambium growth is active and the bark should slip. Then, with good scion pieces in hand, one uses a small cleaver or good-sized knife to make two parallel cuts into the bark about 4 or 5" long (the same width as each scion piece and about 6" in length).

Next, one side of the scion is cut away except for the top inch. Then the outside base of the scion is cut away at a short angle. Now one pulls loose the narrow strip of thick bark and shoves the pointed scion piece under this bark and down the groove until the cutaway area is no longer exposed. One or two good buds should still be showing on the scion tips that remain above the level of the sawn-off rootstock. Repeat this procedure three or four times on large diameter cuts to speed its healing over. A small brad can be used to nail into place. Most of the bark strip that has been pushed out can be cut off, but not the bottom portion that's in contact with the small bottom wedge cut of each scion piece. Now you can wrap with plastic tape, tar over any exposed cuts, plastic bag and finally cover over the works with a perforated paper bag for shade.

In two or three weeks you should check for growth and then remove bagging. It will soon be necessary to fasten lath or stake pieces to the trunk to support the fast growing scion growth. Otherwise the weight of the new shoots can easily cause them to break off. By pinching back some scions and encouraging others, one can design a shapely new tree. All this new growth speeds the healing of the large cut-off area.

This method has given dramatic results for me with mangos, white sapotes and Eastern persimmons so far. I have seen large avocado and macadamia trees similarly top-worked by using the saw cleft graft whereby an angled wedge is sawn out to accommodate conversely cut scion pieces. How satisfying it is to transform such big unsatisfactory trees into a tree of a prime variety in just a couple of years!

By planting seed of high-quality fruits and letting them fruit out, some fine well-adapted cultivars are bound to appear. Unsatisfactory seedlings can be top-worked. Someone will discover some mango cultivars just as suited and gratifying as the Anna cultivar of apple has proved to be for Southern California.