- Prunus dolcis
- Cultivation and Historical Use
- Growing Conditions
- Recommended Varieties and Cultivars
- Proper Planting Practices
- Pests and Diseases
- Almond Quick Reference Growing Chart
- Highly Rec-almond Giving Almonds a Go
- Almond Tree Overview
- Caring for Your Almond Tree
- Almonds Are Fruit! Should you Eat Them?
- Walnuts are fruits, not nuts – but does it matter?
From candy, to marzipan (my all-time favorite), to the boom in almond “milk” interest, people are absolutely nutty about almonds, and rightly so.
Believe it or “nut” (if you don’t like puns, you may have come to the wrong place – we’re just getting started), this coveted tree crop has been cultivated from as early as 4,000 BC – and shows no sign of dropping out of fashion any time soon.
In the same family as other firm favorites such as peaches, cherries, plums, and apricots, almonds provide a delicious, nutritious, and extremely versatile addition to any homestead or garden.
As the earliest-flowering stone fruit, the almond tree has the added bonus of also being an ornamental flowering tree, growing 10 to 15 feet high, and replete with fragrant pink or white flowers in early spring.
Beautiful as well as delicious – what’s not to like? As often is the case with beautiful things, these delicious nuts come with a few hang-ups… read on to find out more about what it takes to grow almond trees.
Cultivation and Historical Use
Cultivated as early as 4,000 BC, almonds (Prunus dolcis) are thought to be native to central and southwestern Asia, although their exact ancestry is unknown.
Throughout history, these nuts have had a lot of religious and cultural importance. They even merit a mention in the Bible, when in the Book of Numbers, Aaron’s rod blossomed and bore almonds.
The Romans also held a special place in their hearts for almonds, showering newlyweds with the nuts as a fertility charm, and there are records suggesting that they were a prized ingredient for Egypt’s Pharaohs.
Today, some Americans give out sugared almonds at weddings, as a representation of children, happiness, romance, good health and fortune. In Sweden, they are hidden in cinnamon-flavored rice puddings at Christmas to bring luck in the coming year to whoever finds them.
Explorers are supposed to have eaten them while travelling the Silk Road between Asia and the Mediterranean, where it didn’t take long before they took root and flourished, especially in Spain and Italy. Today, we often associate the nut with California, although they actually weren’t introduced there until the mid 1700s, when they were brought over from Spain by the Franciscan Padres.
They didn’t immediately take to life in California, however, and it took years of research and crossbreeding to help them adapt to their new, cooler life on the coast. By the 1870s, they’d cracked the problem (along with many, many nuts in the process) and now they are firmly established in California’s Central Valley.
Almonds are sensitive souls, and are fussy about their growing conditions, which unfortunately means they can be about as challenging to grow as they are delicious.
The trees require hot and dry conditions, thriving in USDA Plant Hardiness Zones 7 through 9 as they especially enjoy areas that have long summers with hot, dry, sunny weather, and therefore a long growing season.
That being said, they also have a need for a certain amount of cold (around 200-400 hours per year at temperatures less than 45°F/7°C ) to successfully break the dormancy of their buds. This is why they’re not well adapted to tropical climates.
They are particularly intolerant of wet soils and frosts, and as such are well suited to places like California and the East Coast. This is a problem for the early flowering almond, which is particularly vulnerable to frosts.
P. dolcis loves the sun. Although they will tolerate partial shade, they won’t flower or fruit nearly as well as they would if planted in in full sunlight.
Although they prefer well-drained, deep, loamy soils, they will tolerate other soil types, including poor soils, as long as they are not wet or poorly draining, which they absolutely cannot abide.
Conversely, and somewhat counter-intuitively, the trees need ample rainfall (around 500-600 millimeters or 20-25 inches annually) or irrigation to produce good yields and well-filled nuts, although they will survive with less water. Traditionally, they weren’t irrigated until farmers discovered they responded well to just the right amount of help given at the right time.
Although they flourish in semi-arid climates, P. dolcis likes a bit of extra water applied at the right times. Drip irrigation is the best method.
They especially benefit from extra watering in early spring, during the summer, and sometimes during the first months of autumn, but really need a helping hand at the beginning of the growing season, as starting off the season too dry can result in a significant decrease in production.
However, it is important not to water them around or near harvest time, with commercial growers stopping irrigation around 3-4 days before harvest. This means it’s a bit of a guessing game when growing these, and you have to find just the right balance to achieve a good harvest.
Almonds are generally not self-pollinating, so cross-pollination with a second variety is usually required for fruit production.
Recommended Varieties and Cultivars
When choosing your tree, the most important thing to keep in mind is your growing conditions, and which hardiness zone you’re in.
Another top tip is to make sure you buy a sweet almond if you plan to eat the nuts rather than a bitter almond tree, typically an ornamental which is grown more for aesthetic reasons.
There are quite a few standard varieties, including ‘Carmel,’ which gives an excellent, well protected nut and is also an excellent pollenizer, and ‘Mission’ which, despite being a late bloomer, is a very productive tree.
However, ‘All-In-One’ is often suggested as the best backyard variety, thanks to the fact it only grows to about half the size of a standard tree, making it ideal where space is a bit tight, such as in home orchards.
‘All-In-One’ is exceptional as one of the few self-pollinating cultivars, so it has no need of a neighbor for a helping hand in making fruit, adding to its value for the small space gardener. The fruit from this tree ripens in late September or early October, and it is considered a soft-shelled nut.
For a slightly hardier variety, ‘Hall’s Hardy’ is a good bet. This cultivar is just as often planted for its beautiful pink blooms as for its nuts. Ripening in October, it is a full-size almond tree that does better with a a buddy for cross-pollination, so be sure to plant another variety nearby for a good harvest.
‘Hall’s Hardy’ is very cold tolerant – in fact, it even requires a bit of a chill to produce fruit, so this is perfect for slightly more marginal places, recommended for USDA Hardiness Zones 5-9.
Proper Planting Practices
As with all trees, giving them a proper start in life is the key for their future success.
Almonds like a healthy distance from their neighbors, ideally 15-20 feed (4-6 meters) apart.
Before planting, the roots should be given a thorough dosing with water, ensuring that they’re thoroughly wet before they are put into the ground to to get them off to a good start in life.
The hole should be dug wide and deep enough for the whole root system, with special attention given to the tap root so that it’s not bent out of shape. As with many nut trees, almonds are especially sensitive to tampering with their tap root, so they should never be trimmed or forced into a hole that’s not big enough to accommodate it. The rest of the roots should also be sensitively handled, and carefully spread out to prevent matting.
They should be planted to the same depth they were grown at the nursery (you should see the noticeable color difference between the roots and the rest of the plant, which indicates which part should be buried). This is the same for both bare root plants and potted trees.
Soil should be firmly compressed around the roots as you refill the hole. Once the hole has been refilled, you should give your baby tree two buckets of water to settle it in well to its new home.
At this point, you can also give your tree a little boost by adding some fertilizer, though it is best to wait until spring to fertilize if planting in the fall.
By Root Graft
Like most fruit and nut trees, almonds are normally propagated by budding. This is by far the easiest and most effective way to grow them and ensure that they grow true to their parent plant.
A hardy root stock (often of peach or the more resilient bitter almond variety) is used to give the tree resistance to soil-borne diseases, and then the fruit-bearing branch is grafted onto the root stock.
Using grafted almonds makes the trees much more resilient, and they often grow much faster than from seed. This is particularly the case for those that have a peach root stock, which generally tends to be more productive than those grafted with almond root stock.
A further complication with almond trees is that you have to have at least two different, but compatible, varieties so that they can cross pollinate, usually via bees.
From the Nut
It’s perfectly acceptable to try growing your own from seed for a backyard project, as long as you are aware that it will take much longer to bear fruit, and any nuts that are produced may not be of the same quality as that of the parent plants.
Find fresh nuts – not roasted like you find in the supermarkets. Leave them to soak for around 48 hours, and then place them on a wet paper towel in a plastic bag and place them in the refrigerator.
About 3-4 weeks in the refrigerator should do the trick, and the almonds should start sprouting. At this point, they’re ready to pot in a nice, well-drained soil mix (something like a mix of sand and compost) and placed in direct sunlight, ideally on a windowsill where it’s nice and warm.
The important thing is to keep them moist, but never soggy. After they have reached about 6 inches in height, they’re ready to be moved up to a bigger pot size.
Pruning has different purposes at different stages of the tree’s life.
Pruning young almond trees determines their future shape, and therefore their productivity and the quality of the nuts produced. It’s important to get it right to ensure a good harvest.
Almonds are commonly pruned into a “vase” type shape with 3-4 main branches, which also allows for ease of harvesting. If done correctly, the “vase” shape makes the tree more vigorous, more productive, and guarantees a longer lifespan.
Pruning after maturity, however, is more about maintaining the shape established in the early stages of the tree’s life. Pruning renews the tree and stimulates it to produce more. Around 20% of an older tree’s canopy should be pruned back each year.
For more information on proper pruning practices, check out our guide (coming soon!).
Harvesting looks really fun, and that’s because it is!
Safely wrapped up in their shells, all it takes is a hard shake to make the nuts fall to the ground, where they can be gathered.
Top tip: it’s best to shake the trees over a sheet so they can be easily collected afterwards.
You’ll know they’re ripe for a picking (or a shaking) when the hulls start to split open, often from late summer through to October in the US. If you wait until about three-quarters of the nuts have started to split, it’s a safe bet to harvest them.
The nuts must be dried before consumption, which can either by done by leaving them on the ground for a few days after shaking them (if there’s no risk of rain where you are), or storing them safely somewhere cool and dry.
The average healthy and mature almond tree can produce a tree-mendous 50-65 pounds (23-30 kilograms) of nuts.
Pests and Diseases
Almonds, as I’ve already mentioned, are sensitive souls. They therefore may suffer from a number of afflictions.
They are particularly susceptible to soil-borne diseases, such as the fungal disease Verticillium wilt. This causes all kinds of drama for growers around the world every year, and enormous economic damage for commercial growers.
Verticillium wilt can be avoided by using a grafted specimen with a hardy root stock of peach or bitter almond. It’s also important not to over irrigate, which encourages the kind of conditions that verticillium thrives in. Soaker hoses are your best bet.
Apart from that, these trees often suffer from the bacterial disease known as crown gall. This usually gets into the tree via cuts, so care should be taken not to damage the tree. If pruning, always cut branches with clean, disinfected equipment.
Almonds may also have issues with mites, such as the brown mite and the red European mite, which stress the tree out and cause damage to its leaves.
If using an IPM program in your garden, these mites are best controlled with an oil spray during the trees’ dormant period, or through introducing natural predators such as the Western predatory mite.
There are also some pesticides which are effective against mites, including some pyrethroids.
Almond Quick Reference Growing Chart
|Plant Type:||Nut tree||Tolerance:||Mature trees somewhat drought tolerant; low chill hours required (200 or less)|
|Hardiness (USDA Zone):||5-9 (temperate-subtropical)||Soil Type:||Loose and sandy to loamy; does not do well in clay|
|Season:||Spring and summer||Soil pH:||5.5-8.5|
|Exposure:||Full sun||Soil Drainage:||Well-draining|
|Time to Maturity:||180-240 days, depending on cultivar||Companion Planting:||Cover crops like clover to aerate, facilitate water penetration, add nitrogen, and attract pollinators|
|Spacing:||14 feet minimum||Family:||Rosaceae|
|Planting Depth:||Same depth as nursery pot, or set crown of bare root stock just below soil surface||Genus:||Prunus|
|Spread:||10-15 feet||Species:||P. dulcis|
|Water Needs:||Low to moderate|
|Attracts:||Bees and other pollinators|
|Pests & Diseases:||Mites, navel orangeworm, peach twig borer, verticillium wilt, crown gall|
Highly Rec-almond Giving Almonds a Go
Okay, maybe “rec-almond” was a stretch… but we do highly recommend it!
Overall, despite being a bit finicky, almonds are definitely worth a shot in your garden.
With a bit of light, warmth, and TLC, this can be a beautiful and rewarding tree to have in your back garden.
Nuts about nuts? For further reading, check out the following articles:
- Death by Black Walnut: The Facts on Juglone Toxicity
- With a Bit of Patience, Here’s How You Can Yield Masses of Pecans
- How to Grow and Care for a Macadamia Nut Tree
© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Uncredited photos: .
About Natasha Foote
With a passion for soil health and growing trees, Natasha Foote is a biologist who was hit with a serious case of green fingers, and decided to swap sterile laboratories for getting her hands dirty in the soil. Formerly a farmer and researcher working with the agroforestry project Mazi Farm in Greece, when she wasn’t working on the farm, she was busy studying soil biology under the microscope. Now, you can find her in the south of France where, in between enjoying all the fresh peaches, plums, apricots, and cherries that the area has to offer, she’s working on various agricultural projects whilst writing about all things green.
Almond Trees are fairly hardy, but if you want to harvest the nuts, make sure to give it plenty of water and sunlight, with a cold weather snap during the winter.
Almond Tree Overview
|Scientific Name||Prunus dulcis|
|Type||Deciduous fruit tree|
|Common Names||Almond tree|
|Watering||Maintain moist, well-draining soil|
Almond trees come in bitter and sweet varieties. Bitter almonds are mostly grown for ornamental purposes, while sweet almond varieties are what you will need if you plan to consume your almond fruits.
This compact variety is ideal for smaller spaces as it grows to around half the size of an average almond tree, and unusually, this almond tree is self-pollinating, so it does not require you to plant more than one.
This variety is especially hardy and produces an abundance of stunning pink blooms. (Utah State University).
This almond tree blooms later than most but is very productive.
Caring for Your Almond Tree
Giving your almond tree the best start in life is essential for developing a healthy, thriving tree. The ideal time to plant an almond tree is in the fall, as these trees have a rapid early growth phase, and this will ensure they develop strong roots before winter. You can plant the tree at other times of the year, but be careful to protect the tree from frost and heatwaves.
First, choose a spot for your tree which has full sun but is protected from cold winds. Almond trees prefer a pH of around 6.5, though they will grow well in just about any soil type. The exception to this is soggy, poorly draining soil, which is not suitable for almond trees. They can handle a variety of soils, including sandy, loamy, and clay, but they absolutely must be in well-draining soil. If your soil is not well-draining, you can add in organic matter and sand to increase its draining capacity.
Dig a hole for your almond tree at least the same depth as the root ball. This is important because the taproot is sensitive and should not be bent or forced into a space too small for it. The hole should be wider than it is deep, roughly twice the width of the root ball itself. Soak the roots with water before you plant them and gently spread them out in the hole. Fill the hole with topsoil and ensure it is well compacted without air holes. Add extra soil around the trunk of the tree to create a slightly raised angle that will encourage water to drain away from the trunk and prevent rot.
Once planted, add several buckets of water to the tree to help it settle. Young trees may need to be staked to help keep them in an upright supported position, but stakes should be removed when the tree is able to hold its own weight, to allow it to grow without restriction.
Almond trees are not self-pollinating, and therefore. if you wish to see fruit, you will need at least two different trees planted in close proximity to each other to allow for cross-pollination. As a guide, the trees should be planted between 15 and 25 feet apart, but if you are short on space, then you can actually plant two almond trees in the same hole. The trees will grow with intertwined trunks and will ensure cross-pollination of the flowers.
When the almond tree is young, it will need plenty of water, as much as 3 inches each day. As the tree becomes established, you can cut back on watering to 3 inches per week, dependent on its conditions and the time of year.
Although almond trees enjoy hot, dry conditions, they do need lots of water to set fruit. Almond trees can survive in almost drought-like conditions, though these trees are unlikely to produce an abundance of fruit. If the fruit is not important to you, and you are growing your almond tree an ornamental, then watering will not need to be as much of a consideration. If you want your tree to produce fruit, you will need to pay more careful attention to your watering regime as almond trees can be quite finicky.
Give your tree extra water early on in the growing season, as a lack of water during this time typically results in a poor yield of fruit. Extra water can also be beneficial during hot, dry summers and at the beginning of fall. However, you must ensure that you stop watering your almond tree several days before you harvest the fruits. This allows the fruits to dry out and does require some guessing as to when the fruits will be ready to harvest.
Although the tree does benefit from additional water throughout the year, always be careful not to overwater the tree as it will not survive in wet soil.
Almond trees should be planted in a position where they will receive full sun. They need at least six hours of direct sun each day, but a greater amount of sun will result in a greater abundance of fruit. The tree can survive in partial shade, but it will produce a much smaller volume of flowers and may struggle to set fruit.
Almond trees like climates that experience long, hot summers, providing them with a long growing season. During very hot summers, you can whitewash the trunks of almond trees to protect them against sunscald. Although they enjoy the heat, they also require a certain amount of cold weather in order to break the dormancy of buds. Ideally, the tree should get between 300 and 400 hours each year of temperatures that are lower than 45 °F. This requirement is the reason why almond trees do not grow well in tropical climates, as they don’t get cold enough for long periods of time. However, it makes the almond tree ideal for growing in climates such as those found in California and states on the US east coast.
The almond tree is hardy to USDA zones 7 to 9 and will struggle outside of these regions. Although the tree requires a period of cold weather, frost can cause problems for it. Though the tree itself can cope with frost, it can affect the development of flowers, which will, in turn, affect fruit production.
When the tree is young, you should prune it to encourage good shape, which will result in a healthy tree and ensure a long productive life. Prune it in winter during its dormant period, cutting out all of the weaker branches, leaving just 4 or 5 main branches remaining.
Once the tree is established, your pruning will be about maintaining the shape, as well as encouraging new growth. Cut out any branches that are growing back toward the tree and any outside of its natural shape. Aim to remove around 20% of a mature almond tree’s branches each winter when you prune, as this will promote new growth and ensure the tree continues to renew itself.
Thinning out branches will also help light to penetrate the tree and increase airflow, which will help with flower production and the tree’s overall health. You should also prune back any dead or diseased growth at any time of year (University of California).
To harvest your almond tree, all you need to do is give the branches a shake. As long as the almonds are ripe, they will drop to the ground where you can collect them.
Almond trees are typically ready for harvesting in the fall. You will know they are ready when you see their hulls popping open. When the majority of fruit on the tree is bursting out of their hulls, you will know it is time to shake your tree. It’s a good idea to spread a sheet or tarpaulin on the ground to make for easy collection.
Once you have gathered your fruits, you will need to remove them from their hulls and allow them to dry out fully before they can be eaten. To do this, simply store them in a cool, dry spot for a few days. Some people leave the fruits on the ground for several days before collecting them, as this gives them a chance to dry out, but this should obviously only be done if you are sure that it won’t rain.
Almond trees are most commonly propagated by root graft. This ensures that the new tree is an exact copy of the parent tree, and means you can rely on it producing good fruit. Use a hardy rootstock, ideally peach, and then graft a fruit-bearing almond branch onto the rootstock.
You can also grow the tree from seed, but this will take much longer and may produce a tree different from the parent plant. To use your almond nut for propagation, soak a fresh nut in water for 48 hours. Then, set the nut on a paper towel and enclose it in a plastic bag. Leave the bag in a refrigerator for around a month, at which point you should see some sprouts forming.
Once you have sprouts, you can plant the nut in moist, well-draining soil in a pot. Position it on a warm and bright windowsill and wait for more growth. At around a height of 6 to 8 inches, you should transfer it to a larger pot. Once the tree has developed a strong root system, you can plant it outside.
Almonds Are Fruit! Should you Eat Them?
Posted on : April 2nd, 2018
Did you know that in some parts of the world almonds are eaten as a fruit? It’s true! The nut that we typically eat in the Western world is actually the inner seed of the almond fruit pit, known as a drupe. Almonds are in the botanical family “Prunus” which is the same family as plums (prunes), peaches, cherries, nectarines and apricots. All of these are also known as “stone fruits” because the fleshy and often delicious fruit that we typically eat surrounds a hard stone or wood-like seed found inside. Usually these seeds are never eaten—in some cases they might even be poisonous! In fact, a form of almond called “Bitter Almonds” fall into that category. But the ones we eat, also known as “Sweet Almonds,” are not only good to eat, they’re good for you!
But back to the fruit. Should you eat them?
Well, good luck with that! The season for almond fruit is extremely short, only a few weeks long in the Spring. The almonds need to be eaten before the nuts inside start to harden and while still fresh—which means green—and only keep in the refrigerator for a few days. They’re actually considered best the same day they are picked. That makes them a bit of a rare delicacy and some people definitely think of them that way! But other people consider them at best . . . interesting.
The texture varies depending on almond variety and when they are picked from gelatinous to somewhat creamy inside a crunchy fuzzy outer skin. The entire fruit is eaten, including the soft developing seed which is often considered the best part! The taste is a bit difficult to describe. Delicate. A little tart, a little like a vegetable, a little almondy, especially late in fruit-eating season.
In places where they are regularly eaten, the most common approach is to sprinkle them with olive oil, dip them into salt or sugar, and just pop them into your mouth! But you can also slice them and add them to salads, make them into soup, or even pickle them!
I came across a video that I’m sharing with you today by someone who calls himself the “weird fruit explorer.” It’s part of a series where he tries a little known fruit for the first time and reviews it in real time. His first impression of green almond fruit was amusing! I think you’ll enjoy what he had to say.
Maisie Jane’s California Sunshine Products, Inc. was founded on strong beliefs and passion for offering unique, flavorful, top-quality, nut products. We strongly believe in earth-friendly practices that start on our family owned and operated orchards. We use Organic farming practices and continue in the process by using all-natural ingredients with no preservatives or GMOs. We believe in honest, friendly and helpful customer relations at all levels. We take pride in every task, every day, with every person.
Fruits with these characteristics are called “drupes”. Specifically, a drupe is a fruit that has an outer fleshy part surrounding a shell that contains a seed. Other drupes include fruits from walnut trees and coconut trees.
The seed inside the almond fruit is what is commonly referred to as an almond “nut”, even though it’s not a nut. A nut is a hard shelled fruit that has an indehiscent seed; more simply, a hard shelled fruit that doesn’t open to release its seed(s). An example of a true nut would be an acorn or chestnut.
This all gives a whole new perspective to the famous Almond Joy jingle “Sometimes you feel like a nut; sometimes you don’t”. When you feel like a nut, an Almond Joy wouldn’t do you any good due to the ingredients primarily comprising of chocolate (bean), coconut (seed), and almonds (seed). The ending of the jingle, like so many advertisements, is then just plain false advertising: “Almond Joy’s got nuts” (LIES!!!), “Mounds don’t”.
If you liked this article and the Bonus Facts below, you might also enjoy:
- Peanuts are Not Nuts
- Bananas are Naturally Radioactive
- Why Doctors Have Men “Turn Their Heads and Cough” During a Physical
- The Best Ways to Lower Blood Pressure Naturally
- Other “nuts” that aren’t include Brazil nuts, Cashews, Walnuts, Coconuts, Macadamia nuts, Peanuts, Tom Cruise, and Pistachios, among others. OK, so Tom Cruise is a nut, but in a totally non-botanical way.
- The almond tree itself is a cousin of the peach, cherry, and apricot trees. The tree is medium sized and bears fragrant pink and white flowers.
- Almonds come in two varieties, sweet and bitter.
- The bitter form of almonds contains a toxic amount of prussic acid. Prussic acid, for those who don’t know, can be further refined into cyanide. Just a handful of unprocessed bitter almonds is enough to kill most people. Processed bitter almonds though can safely be eaten as all the prussic acid will have been leached out.
- About 1.7 million tons of almonds are produced every year world-wide with the United States, specifically California, producing about 80% of the world’s almonds and 100% of the U.S.’s commercial supply of almonds.
- Close to one million bee hives, which is about 50% of the U.S.’s total number of bee hives, are used to pollinate California’s almond groves.
- Almonds are mentioned ten times in the Bible. According to tradition, if the Israelites followed the Lord, the almond trees would give forth sweet almonds, but if they forsook the Lord their God, the trees would give forth bitter almonds.
- The Almond blossom provided the model for the Jewish menorah: “Three cups, shaped like almond blossoms, were on one branch, with a knob and a flower; and three cups, shaped like almond blossoms, were on the other… on the candlestick itself were four cups, shaped like almond blossoms, with its knobs and flowers”.
- In Christian tradition, the almond branches are used as a symbol of the Virgin Birth of Jesus. If you pay attention, you’ll notice that paintings of this scene often include almond branches encircling the baby Jesus.
- Blanched almonds are shelled almonds that have been immersed in hot water to soften the seed coat so that this coat can be easily removed to reveal the white insides.
Expand for References
Walnuts are fruits, not nuts – but does it matter?
Have you run into people with severe nut allergies who will eat peanuts, because they are legumes, not nuts?
Or have you placed a fruit platter on the table and heard a guest say that those bananas and oranges are actually berries?
We asked a biologist why scientists classify things in the plant kingdom so differently from the rest of us.
Anne Krag Brysting is a professor in plant taxonomy at the University of Oslo.
The ovaryof a common garden plant. (Photo: Paintser)
She explains that biologists divide nature into categories to make it easier to communicate with one another. Fruits and other types of vegetation are categorised according to their basic structures.
Chili is a berry
Fruit in a botanical context is the seed-bearing part of a plant. Fruit is the mature ovary or ovaries of one or more flowers. When the ovary swells up it becomes a fruit with one or more seeds inside.
Brysting says biologists generally look at three things when dividing fruits into types: Whether the fruit is dry or fleshy, whether if breaks apart to discharge seeds or doesn’t and whether it is composed of one or more ovaries.
There are simple fruits, which develop from a single or a compound ovary. These can have dry flesh. Then there are aggregate fruits, which do not develop from just the ovary, but also the flower itself. These are also known as false fruits, as some of the fruit is not from the ovary, but from the adjacent tissue. Strawberries, apples and pears are typical false fruits.
Almonds are the seed of stone fruit, or drupes. We eat the fruit wall of the peach. The coconut is filled with the nutrients the seed needs to grow. (Photo: / NTB scanpix)
Adding to the confusion, we eat different parts of fruits. The part that is edible, however, is not the concern of biologists when placing plants into their categories.
It is hard to picture, but coconuts, almonds, peppercorns and mangoes are all the same sort of fruit. They are stone fruits, also known as drupes.
This is because we eat the seed of the almond, on mangoes we eat the fruit wall or pericarp, on pepper we eat the entire fruit, usually after grinding it, and when it comes to coconuts we eat the nutritient part which is meant to serve the seed as it grows.
If we compare drupes they have their similarities. They have a rather thick peel or shell and they have one seed with soft fleshy fruit around it.
Numerous types of cabbages have been cultivated, originally descending from wild cabbage. (Photo: Shulevskyy Volodymyr / / NTB scanpix)
Berries have much in common with drupes, but they usually have multiple seeds. So they are called aggregate fruits.
On exception is the avocado, which Brysting informs us is counted as a berry, even though it only has one seed.
Among the berries you also tomatoes, chilies, blueberries, melons, oranges, bananas and kiwis.
But raspberries and blackberries are not categorised as berries. They are not just one fruit, but rather a cluster of small stone fruits that have grown together. These have more in common with a mango — or like a bunch of small mangoes.
Wild cabbage led to broccoli
Biologists do not think in terms of vegetables when categorising members the plant kingdom. The word has no clear biological meaning because vegetables are one or more parts of a plant that can be used in various ways.
Brassica olerace, or wild cabbage, is a good example of a plant that is used as a food. All types of cabbages descend from them, says Even Brattberg of the Norwegian University of Life Sciences (SNL).
Head cabbage developed down through pre-history and history as humans repeatedly planted seeds from the plants that grew with the largest buds and the shortest stems.
This is selection in animals is breeding and cultivation when it comes to plants. Plants that have characteristics which can be maintained through propagation, mainly by us, are called cultivars.
Kale, or leaf cabbage, is the nutritious flower of the plant. Broccoli is a cultivated flower and stem. Kohlrabi, or turnip kale, is a cultivar with an edible stem.
So many things
In addition to all the different cabbage varieties and offspring we have carrots, which are roots; peas which are the seeds of a legume; onions which are leaves; ginger and turmeric which are underground stems – or rhizomes.
The latter two lead us from your fridge to your spice rack. Spices are another category with no botanical meaning. Spices can be just about any part of a tree or plant, from leaves and flowers to bark and roots.
But biologists do recognise the herb! And what qualifies as an herb? It is a seed-bearing plant with aerial parts that do not persist above ground at the end of the growing season. In other words, the part we see dies. It is also a plant with no bark on its stem, points out Halvor Aarnes, a plant physiologist at the University of Oslo.
This gets mind-boggling again, because bananas are herbs but that rosemary you probably have in your cupboard is not.
Brysting explains that in biology and botany there are always things that don’t fit fully well into the pigeonholes we have given them, and fruits are no exception – because they too have exceptions.
Most of the classifications of fruit come from Germany, centuries ago. The categories were made on the basis of the fruits that were available at the time. So some exotic fruits like the lychee and the rambutan are pieces that don’t fit into the jigsaw systems well.
Botanical hair-splitting and definitions are not that important in our daily discourse, admits Brysting. So we are not wooden-headed when we call a walnut a nut, even though botanically it is a stone fruit, just like peach.
With a clear conscience we can call a raspberry a berry and a peanut a nut. No need to give your grocer a hard time for placing carrots and cabbages in the vegetable section.
Read the Norwegian version of this article at forskning.no
Translated by: Glenn Ostling
- Anne Krag Brysting’s profile