Apr/12/2016
Blossoms / Citrus / Fruit / Life Cycle of Plants / Seeds / Trees

Fruit Trees and Their Blossoms: Hands-On Activities for Spring

Has your child noticed the signs of spring? Have you heard comments about daffodils, new leaves, green grass, or even the smell of nature unfolding after her winter’s nap? One of my favorite signs of spring is the multi-sensory experience of blossoms. What can seem like overnight, suddenly there are pink and white trees with beautiful flowers and delicious fragrances. I am not the only one who relishes the sight of blossoms. In Japan and Washington, DC Cherry Blossom Festivals and tourist activities are a highlight of this season.

 

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Not every flower is a blossom. Flowers are the reproductive part of the plant. With the help of pollination, the purpose of a flower is to eventually create seeds so the plant can reproduce. The term blossom is generally reserved for the flowering part of a plant that will turn into a fruit, nut, or berry. Here in Arizona, we also refer to saguaro blossoms or the beautiful flowers on those iconic cacti with what appear to be arms.

 

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For this post, we will focus on the blossoms on fruit trees, or apples, pears, plum, and cherries to name a few. If a fruit has a single seed, it is called a stone fruit. Stone fruit is also referred to as drupe. This word is a botanical term I had never heard before, but it is kind of fun to say. Few people will know what you are referring to so you and your child might want to start using this term and share a reference that only the two of you understand. Drupes, with their single seed surrounded by fleshy fruit and a thin skin, are different from apples and their kin which are known as “pomes” and have cores containing multiple seeds in separate chambers.

 

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We will also include in this discussion reference to citrus trees or oranges, tangerines, lemons, and grapefruit. The term blossoms can also apply to the flowers that turn into berries and nuts, but these are distinct processes and will be reserved for a later activity post.

 

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Questions

Have you heard any of these questions? If not, perhaps you can begin a conversation with a prompt, “That tree is so beautiful this time of year, I wonder what is making it look so pink.”

 

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What are blossoms?

 

What colors can they come in?

 

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How do they develop or grow?

 

Why do they smell so good, sweet or fragrant?

 

Where does the fruit come from? Or, How do plants produce other plants?

 

The following more general questions about plants are helpful to ask periodically, or what do plants need to survive (water, nutrients, sunlight).   Also, consider the interrelatedness of living things. We are dependent on plants for carbon dioxide and food as are other animals. Ask what has a plant done for you today? Alternatively, consider what living things plants are dependent on (pollinators)? You will find these general questions about what living things need to survive and relationships among them as forming the foundation of science curriculum in pre- and elementary schools.

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Observe

There is so much to examine, where to start? Follow your child’s lead, but here is a variety of options for observing that you can suggest or demonstrate.

 

Getting up close to a flowering tree in full bloom is going to provide the best opportunity for examining its’ blossoms, but driving around and keeping an eye out for blossoming trees may be a good distraction from those routine car rides.

 

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A magnifying glass is essential for a close look. Drawing or sketching what one sees hone observation skills. Taking photographs (with a phone is fine) also results in fine-grained observations, but consider inviting your child to examine the flower carefully and then take a picture.

 

Stop if you see a tree with blossoms. Look closely at the flowers with a hand lens. Guide your child’s examination to include answers to the following: What do you see? Describe the color/colors, the number of petals, the shape of the petals, and other parts.

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If looking down on those blossoms, can your child identify shapes? Flowers come in two general shapes. The first kind is described as radial symmetry. These flowers can be divided into equal sections that are the same. Irregular flowers can not be divided, and there is no symmetry. Symmetry is a pattern that is typical in much of nature. This characteristic is a good thing to look for whatever the topic or interest. The term symmetry may not be on the tip of your child’s tongue, but he probably can recognize the construct of something being made up of equal parts. Just as we have two legs, two arms, two eyes, two ears, and one-half of our body looks just like the other half if you were to draw a line down the middle from head to toe.

 

What do the blossoms feel like?

 

What do they smell like? Find the language to capture the elements of the scent. What does the smell remind him of? Consider in this discussion what might be the advantage of a sweet or pungent odor (sweet attracts pollinators whereas a pungent odor generally repels, but can attract pollinators that prefer something stinky).

 

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Blossoms won’t make a noise but perhaps listen for birds or bees enjoying the tree and its bounty of color. What do they sound like?

 

What happens to those blossoms when the wind blows (the petals scatter and blanket the ground)?

 

Don’t forget to invite your child to check out the rest of the tree. About how high is it? If it seems small, it could be a dwarf tree. The size of the tree will also depend on whether or not it was pruned. Can you see evidence of pruning or cutting limbs? What is the shape of the canopy (umbrella-like, or maybe the tree is more of a cone)? Look closely at the bark. What color or colors is it? What is its texture (rough or smooth)? What do the leaves on the tree look like? What shape are they? What color and texture are the leaves? Some leaves are shiny, and others are dull. Are these characteristics of the tree that your child has noticed or that you can suggest she look at and feel?

 

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Perhaps suggest he examine what type of soil the tree was planted in. Is it moist or dry? Is it sandy or dark and nutrient rich?

 

Where is the tree planted relative to the wind direction or amount of sunlight? Stone fruit are typically not planted on the top of a hill because the wind is stronger on a hilltop and may blow the blossoms apart. Stone fruit and citrus trees need considerable sunlight. Is this the case for the tree your child is examining?

 

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If you have a blossoming tree nearby and can visit it regularly, consider drawing or photographing its progress over the next several months. That is, visit it regularly, every couple days or weeks depending on your schedule, and ask your child to document its growth.

 

Blossoms need to be pollinated to become fruit. What or who is doing this work? Can you see insects flying in or around those blossoms? Do they stop flying and perch or walk into the flower? Can you see the pollen they are going to disperse? Can you see that pollen on their backs or legs? The advantage to the tree to have all its’ blossoms blooming at the same time is that pollinators can move blossom to blossom doing their work.

 

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Flying insects are not the only animals interested in those trees. If you have a tree or know anything about orchards, you are aware that pest management consumes a good deal of energy. Can your child find evidence of pests either insects, birds, or mammals (mice, rabbits, deer), nibbling on the fruit?

 

Can you and your child find the ovary? Flowers have several different distinctive parts, but for our purposes here, three are important. Flower stamens are the male parts that produce pollen. Flowers have two or more stamens, and these usually form a ring around the pistil or the female part. The pistil is in the center of the flower if looking down and inside of it. On top, a feature called the stigma is sticky so that it can catch pollen. Stigmas can be hard to see. From the stigma, as your eye moves down the shaft (or what is called the style), at the bottom is the ovary that will eventually become the fruit. It should appear as a slight bulge at the top of the stem and is either just above or below where the petals connect.  This is where the fruit will develop. Stay tuned.

 

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Not every child will be interested in learning or using these scientific labels. The important lesson here is that the flower has different parts with different functions. You can use the labels for accuracy, but your child’s usage of them can wait until he is ready.

 

Those ovaries can ripen into simple fruit, which develops from a single ovary. The ripening can result in fleshy or dry fruit. In the first instance, think apples, pears, or oranges and lemons. The dry version would include almonds or chestnuts.   Remember that the ovaries are trying to develop seeds. What would be the function of that surrounding fruit? That plump, juicy surrounding layer is protective and nurtures those seeds. It is also something that can be eaten. For example, if an animal eats the tasty fruit – seeds and all, the chances are good that the seeds will be deposited later somewhere else when the animal goes the bathroom. This seed dispersal method comes with its own fertilizer.

 

 

 
 

Compare and Contrast

Questions build on questions in any investigation. Comparing things serves multiple purposes, including increasing observation skills and generating more questions.

 

If you have multiple fruit trees in your neighborhood, invite your child to compare blossoms and their trees. What variation in colors can be seen? Are the flowers different sizes or shapes? You may not know what kind of tree it is, but the comparisons are the goal. To determine what kind of tree it is, perhaps you both can ask someone, gather some descriptive information and look up the answer, or wait to see what fruit emerges in a couple of months.

 

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If you do not have flowering trees nearby, or only have one variety, you can still make these comparisons. Here is a site with pictures of a variety of blossoms.   See the Gallery on the following: https://en.wikipedia.org/wiki/Blossom

 

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In Washington DC, there are 13 varieties of cherry trees. Can your child see differences in these images, or distinguish among some of those varieties?

http://mydecorativetree.com/2013/04/washington-dc-cherry-blossom-tree-varieties/#.VwWAizbysoI

 

Compare the fruit and seeds that result. You’ve seen the blossoms. Did your child determine that she has a favorite flower? Now try the results or the different fruits. Does your child prefer apples, pears, cherries, or plums? Peaches and apricots would count too. How about a favorite citrus? Have a taste test comparing the taste of the various fruit growing on those trees that were covered in blossoms.

 

Save the seeds from those taste tests and compare them as well, in terms of their size, color, and shapes. Remember, stone fruit have a single seed and pomes have multiple seeds. Pomes are interesting in that if you cut them along the equator of the fruit, you may see patterns. Think for example of cutting an apple through the center. What is shape can you detect in looking at the seeds (a start is a common reference)?

 

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Explore where stone fruit and citrus trees grow throughout the United States. Here is a map of plant hardiness zones in the US. Find your state and where you live and examine the hardiness zone map. Stone fruit and pome trees are not as hardy as some other trees meaning they do not like to grow where there are really cold winters. However, these fruit trees also generally need a minimum number of annual “cold hours” (generally at least 200-250 or more) to be productive. In arboriculture, cold hours are defined as hours below 40 degrees Fahrenheit. Recommendations are mixed, but apparently stone fruit tress will do well in zones 4 – 7, or even up to 9. Citrus trees on the other hand, like zones 8 – 10 because they don’t do well where it freezes in the winter. What do these temperature difference tell you about these different types of trees?

 

With a little work searching on the internet your child can explore all the different types of fruits and the blossoms or flowers that they came from. You could create a set of flashcards with pictures of the different flowers and the fruits that they will grow into. This is a good way to emphasize a growing cycle and lay the foundations of understanding where all our different kinds of fruits and vegetables come from.

 

 
 

Measure

If you have been documenting the progress of blossoms on a tree, consider determining the answer to the following questions.

 

What was the average temperature outside when those blossoms appeared?

 

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How long did the blossoms last? The best measurement would be if your child can pin point on a calendar when the blossom opened, but if you start later in the blossom’s life cycle, no worries.   What is the approximate length of time those blossoms are on the tree? Cherry blossoms are out for a limited time period, so this will not involve a waiting game that could be tough for younger children.

 

How long before there is evidence of fruit?

 

How long until the fruit is ripe and ready to eat? This latter question will involve waiting a considerable period of time, so ask the question, mark a calendar and don’t dwell on it further.

 

Measure the size of the ovary once you have found it. Then measure the size of the fruit.

 

In other activity posts we have encouraged you to purchase litmus paper strips to test the Ph or acidity of things. If you have any of those around, and they are inexpensive and can be purchased online, test the acidity of the soil a blossoming tree is planted in. Stone fruit trees need relatively neutral soil. Ph measurements below 7.0 are acidic. Stone fruit trees like their soil to be about 5.5 – 6.5. Citrus trees grow better in a sandier, slightly less acidic soil, or Ph levels between 6 and 7. Who would have thought of soil as acidic? Soil acidity often comes from humic acids which are naturally produced by the decay (biodegradation) of dead organic material. Therefore dark, black organic rich soils are naturally slightly acidic.

 

If you have those litmus paper strips, test the acidity of various fruits. If you have several different types of citrus (grapefruit, orange, lemon, lime) you will notice that generally the more acidic a citrus is, the more sour it usually tastes. Also see our post on acids/bases.

 

http://guidingcuriosity.com/kitchen-science-acids-bases-common-kitchen-chemical-reactions/

 

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Experiment

Dissect a blossom’s ovary. What’s inside? Dissect several different ovaries and compare the results. (HINT: Even though they aren’t from a fruit-bearing tree or bush, sometimes larger simple flower like a tulip can serve for this kind of experiment.)

 

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Elaborate and Glossary

The Cherry Blossom Festival in Washington has a website dedicated to children’s activities. Check it out: http://www.nationalcherryblossomfestival.org/in-the-community/blossomkids/ . There are interactive links, one that does an excellent job explaining the life cycle of the cherry tree.

 

Press and preserve those blossoms to enjoy at a later time once they have disappeared from the tree. You have two alternative strategies that you and your child can select from. First is to collect blossoms and place them between sheets of newspapers. Place the newspaper with the blossoms on a flat surface and put heavy items on top. Wait for a couple of days.   An extension of this activity is to place the blossoms on paper and trace around their edges. Now put the heavy objects on top and wait. Whether you traced or not, invite your child to describe and compare the before and after versions. What happened?

 

The alternative is to place the blossoms between sheets of wax paper and with a hot iron, seal the wax paper together preserving the blossom.

 

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Explore the nutritional benefits of those stone fruits and citrus or the fruit those blossoms grow into and that we consume. Consider how much vitamin C we get from eating or drinking those fruits or their juices. We also benefit from the fiber they provide, and they help to keep us hydrated given the amount of liquid they produce. Remember, an apple a day keeps the doctor away.

 

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Glossary

 

Blossoms

Drupes

Pomes

Seeds

Ovary

Stamen

Pistils

Symmetry

 

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