Macadamia FAQs

Frequently-asked Questions

Q. Where can I buy a tree?
Q. Where can I buy nuts?
Q. Where can I buy a cracker?
Q. Where do macadamia trees grow? Will they grow in ..... (my area)?
Q. How do you prepare nuts?
Q. How do you open a macadamia nut?
Q. How do you plant a macadamia tree?
Q. How far apart do you plant a macadamia tree? - What distance do I need to leave between trees?
Q. Is there a special method for air layering macadamias?
Q. What is this black fuzz?
Q. Why do my trees have a lot of dead and dying leaves? Why do the leaves turn brown?
Q. Why is my 6-year-old tree not producing nuts?
Q. My worker trimmed my macadamia tree and now the leaves are turning brown. Why?
Q. Which variety is my tree?
Q. Which tree variety should I buy?
Q. How do I know when to harvest a Beaumont macadamia tree?
Q. Why do my nuts crack open on the tree? What should I do?
Q. Are macadamias toxic to animals?
Q. How do I get a past yearbook?

Answers

Q. Where can I buy a tree?
A. See this link. buy tree

Q. Where can I buy nuts?
A. See this link. buy nuts

Q. Where can I buy a cracker?
A. See this link. buy crackers

Q. Where do macadamia trees grow? Will they grow in ..... (my area)?
A. See this link. Where macs grow

Q. How do you prepare nuts?
A. See this link. How to process

Q. How do you open a macadamia nut?
A. See this link. How to process

Q. How do you plant a macadamia tree?
A. See this link. How to plant

Q. Should I prune my tree? My tree is covering itself with a flush of new leaves. Growing like mad. Is this the time to prune?
A. Since macadamia trees are evergreen, you can prune them any time that you want. However, for the most part, they do not require a great deal of pruning for themselves. If you are not pleased with your trees shape then go at it. If you open up the tree to the rays of the sun you could make it a subject for sunburn. You can make a suntan lotion using white latex paint mixed half and half with water, then just brush it on the areas that you have exposed to the sun.

Q. What distance do I need to leave between trees?
A. My quick answer is 15 feet by 20 feet. I personally think that will work just fine, especially for a small, personal planting. For commercial planting, I will quote perhaps the most respected grower in California, Paul Thomson, who wrote:

"The layout for a commercial orchard should be based on the size the tree can be expected to attain at 20 to 25 years of age and not on the size when planted. Close planting would be recommended if it were not for the very human failing where the owner simply cannot bear to remove every other tree when they begin to crowd each other for sun and root space. Close planting has the advantage of the trees giving each other wind protection at an early age, shading the ground more quickly thus giving less water evaporation, controlling weed growth and simply utilizing more efficiently the expensive land. A 20' x 20' spacing will find the trees touching at 15 years or even sooner on the more vigorous varieties. At 25 years of age, a 30' x 30' spacing will be touching. The Macadamia is not a fast growing tree, but is moderately fast the first four or five years. When it settles down to bearing good crops, the growth rate drops with the strength of the tree going to nut production rather than to vegetative growth. An average growth rate is about a foot per year in height and perhaps 15" in spread once the tree commences bearing nuts. This is variable since some varieties will exceed this horizontal rate, if a spreading tree, while the taller growing varieties will exceed the vertical rate of growth. The Macadamia is a long lived tree and can be expected to have a useful life of 75 to 100 years during which time it will grow to 45' or more in height with 40' or more spread. In view of the above, a permanent planting should not be closer than 30' x 30' spacing or 48 trees to the acre. If the trees were 20' in the row and the rows 30' apart, an acre would hold 72 trees. By using the equilateral triangle or hexagonal layout, where every tree is the same distance from the other, about 15% more trees can be squeezed in. If a closer planting distance such as 20' x 20' on the square is used, it should be anticipated that the removal of every other diagonal row will be necessary by the 15th to 20th year, leaving a spacing of approximately 28' x 28'."

Q. I am currently air layering apple trees and wondering if air layering of macadamias would need any special method to obtain good results?
A. Air layering for the macadamia is just the same as air layering for apples. There have been several articles in the CMS Yearbook on air layering, including in the latest Yearbook.

Q. My macadamia tree produces racemes of flowers each year, but has yet to produce any nuts. It is a healthy tree, about 12 or 13 feet tall and 8 or 9 feet wide, with lots of new growth, but no nuts. Near it are apple, plum, lemon, and peach trees and strawberry, raspberry, blueberry and tomato plants, all of which produce fruit. Is it possible that my mac tree is not self-fertile? My particular tree has four leaves per group on most branches, although a few branches have only three leaves per group at 120-degree angles, so maybe this is an unstable hybrid of Integrifolia and Tetraphylla. In any case, I'd appreciate any suggestions on how to encourage nut production.
A. If you are getting flowers and no nuts the answer is bees. Macadamia flowers are not particularly attractive to bees so if there are other blossoms, flowers around that are more attractive, that is where the bees will go. Additionally, if your tree is in a windy area the bees may not be willing to fly to it. You can us a Q-tip or paint brush to distribute the pollen. However, if you are getting blossoms you are satisfying the needs of your tree, you just need something to get the pollen from one blossom to another. You don't need two trees.

Q. What is this black fuzz?
We have two macadamia nut trees in Vista, CA. They are 15 years old. Until last year they have been healthy and prolific, but last year and this before the nuts/husks fall to the ground, a black fuzz forms in the crack and then the husk becomes black and moldy. Do you have any suggestions about what is happening and what we can do to stop it? Thank you for your review of my question.
A. Black mold is usually associated with either aphids or white fly. Check your trees for an abundance of ants. If you see ants you will need to get rid of them. You can purchase granules at most fertilizer and/or nursery stores to get rid of them. The ants protect the aphids and milk them just like we milk cows. If you get rid of the ants natural predators should be able to take of the aphids. If you have white fly you should see very small white flies if you shake a branch. You can use safer soap (an organic product) or malathion to get rid of both aphids and white fly.

Q. Why do my trees have a lot of dead and dying leaves? Why do the leaves turn brown?
A. Macadamias love water. They came from the tropical rainforests in Australia. If you don�t know what your problem is with macadamias, it is probably not enough water. Sometimes, if only the tips turn brown, you could have a problem with over-fertilization; don�t fertilize a young tree.

Q. Why is my 6 year-old tree not producing nuts?
You and your associates once diagnosed for me a requirement for the addition of chelated iron to my dear friend's ailing macadamia plants. They're now triple the size of what they were two years ago, but my friend is still not getting nuts after 6 years of growth. He says that he has never seen them in flower and is worried that hell will freeze over before flowers - let alone nuts from flowers - will result. His trees are growing in sandy plains of the coast of Perth, Western Australia. He waters adequately and fertilizes them regularly, and he took your collective advice to apply chelated iron - which showed marked improvement. Now he wants flowers and nuts! Can you suggest what to do next?
A. I would guess that you have macadamia trees of the integrifolia variety. They don't always, but they can take quite a few years before they produce their first blossoms. If your trees are growing and they look healthy and green you are doing what they need. When they are ready they will produce blossoms. Then you need to be ready with the bees so that you can get those long awaited nuts.

Q. My worker trimmed my macadamia tree and now the leaves are turning brown. Why?
A. Macadamia trees really do not need to be trimmed, but you can if you don't like the shape of them.� If you open the top so the sun light will be striking the tree it is a good idea to cover that part of the tree with "tree suntan lotion."� Tree suntan lotion is a mixture of 50% white latex paint and 50% water.

Q. Which variety is my tree?
A. There are ten Botanical varieties of macadamia nuts, but only two of those, Tetraphylla and Integrifolia, produce edible nuts.� The other eight varieties produce nuts that toxic to humans. The Cate is a cultivar of the Tetraphylla variety while the Beaumont is a hybrid cross between the Tetraphylla and Integrifolia. The Tetraphylla (Tetra for four) has four leaves in each whorl while the Integrifolia has three leaves. (Look at the end of a branch). The Tetraphylla leaves have almost no stem.� The Integrifolia has a true stem on each leaf. While there are numerous varieties of macadamia trees planted in Fallbrook, two of the most common are Beaumont and Cate. The Beaumont tree (a macadamia hybrid species) will seem to produce nuts all year around. It will set flowers 3 times a year, which is why they were not preferred by commercial growers in San Diego County. They don't want to have to go pick up nuts all year long. The nuts also tend to stick to the trees instead of falling to the ground. The leaves are a little smoother. The nuts are smoother. The Cate tree (a macadamia tetraphylla species) will produce nuts in Fall only, roughly September through November. The leaves are narrow and spiny.

Q. Which tree variety should I buy?
A. It depends on your location, how many trees you are planting and why you are buying a macadamia tree. A tree that will grow best in your location, with your climate, is best answered by your professional local nurseryman (though many local nurseries may not know about macadamia trees). If your local nurseryman doesn�t know (be careful, many will only have one variety and will want to sell you that variety only!) then ask people in your area who have a mac tree. Large growers in most areas have experimented with varieties and know which ones work best commercially. But are you growing commercially, or just one tree for yourself?
Here�s an answer that works in my location, in San Diego County, Southern California. Extensive growing trials were performed in the 1960�s and early 1970�s. The result of this research proved conclusively that in the inland San Diego County area, Cate macadamias performed far superior to any other variety. However, a variety that performed better along the coastal area, which is only a couple miles west in some places, was the Beaumont variety. The two varieties aren�t even in the same species. Taking an individual�s growing needs into consideration, the Cate variety produces nuts in a much shorter period, basically October through December, which is great for commercial growers who don�t want to have to spend expensive labor dollars all year around. But the Beaumont variety can put out fruit (nuts) three times a year. Perfect for the home grower, owner of one or two trees, who wants to have nuts all year long (though nuts will last 5+ years when stored properly). I grew Cates when I was inland in Escondido. Now that I�m back on the coast, I grow a Beaumont.

Q. How do I know when to harvest a Beaumont macadamia tree? Beaumonts do not fall off the tree when ripe. How do I know when to harvest? Also, when I harvest, do I clip off the entire raceme or just the individual nuts?
A. The Beaumont as a variety does have a problem with dropping its nuts. Additionally, if you let the nuts hang too long the shell will crack open and a root will start to grow. They are great back yard trees because they continue to set blossoms throughout much of the year and will also drop some of their nuts throughout must of the year, so you will have something to show your guests. If you want to pick your nuts, pick each nut as soon as its HUSK splits open. One grower that I know harvests all of his nuts when the first blossoms appear in the spring and then after that he picks all of the blossoms - so that all of his nuts are of the same age.� To do that you will severely limit the amount of crop that you will receive, not to mention the amount of work you will be doing. The South African growers industry is heavily Beaumont, and they are experimenting with various chemicals that cause the Beaumonts to drop their nuts. There are several articles in past CMS Yearbooks about this. If you only have one tree, I would suggest that you pick each nut when its HUSK splits open(do not clip the entire raceme).

Q. Why do my nuts crack open on the tree? What should I do? I live in Southern CA and have a 40 year old tree. A lot of the nuts are dropping to the ground split (cracked). Is this normal? If not please advise me what to do.

A. I would expect that the splitting is a function of the cultivars that you have.� Our popular Beaumont variety very definitely has that characteristic.� One way that some of the Beaumont growers circumvent that from happening is they pick the nuts from the tree as soon as the husk splits open.� It would be difficult to do that if your tree is quite large as I imagine yours is. The South African and the Australian growers (large acreages) are experimenting with various chemicals that will cause their trees to drop their nuts (because of the splitting characteristic) but I have not heard of anyone in the US doing that.

Q. Are macadamias toxic to animals?
A. There have been reports on the Internet of macadamias being toxic to dogs. Many mention an article by Dr. Ross McKenzie, a Veterinary Pathologist with the Department of Primary Industries, University of Queensland. If he can confirm that report, it is an important one to read (I have contacted him to confirm the story). In my experience, many large dogs have figured out they can bite through the shell and eat the nuts, but I am not aware of a problem, but that's hardly scientific. One reader, full name unknown, has reported an identical problem. For now, we need to await a response to confirm the multiple-but-identical reports of macadamias being toxic to dogs.

Q. I would like to know how should I proceed to buy the CMS Yearbook for 199xx. Could you send me details on payment and shipment?
A. The CMS has published a Yearbook annually since 1955. The 2003 Yearbook just came off the printing process. They sell for $17.50 each plus shipping. Our address is P. O. Box 1298, Fallbrook, CA 92088. Tell us what you would like to receive and send us a check for the Yearbooks and we will ship them and send you a bill to cover the shipping.