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Frequently Asked Questions
Students' Questions and Experts' Answers
Contributed by Tulip Expert Eve Blanchard
Ways to use in the Classroom

Special thanks to Eve Blanchard for providing her time and expertise in responding to your questions below.


From: Utah

Q: I built a solarium on to my house and it shades the area my yellow Darwin tulips are planted in. Only 1 or 2 of the 6 of them have emerged, although all my other tulips are up (those not planted in shade). These tulips have bloomed marvelously for the past 2 springs and emerged in February the past 2 years. Is it possible they will still come up and bloom, or should I plan to dig the bulbs and move them to a full-sun area for next year, or are they doomed if they don't come up? I think they bloomed in early May the past 2 years. The area does get some late afternoon sun, but not too much. If I should dig them up, when would be the best time to do so? I hate to lose them. They are my favorite.

A: It's possible that something other than the amount of sunlight (and thus soil warmth) has affected your bulbs. For instance, moles or other creatures may have eaten them, or they may be diseased. A lack of sunlight may have kept your soil cool enough that the bulbs are delayed, but this sounds like an awfully long delay. If the soil was both cool and wet, the bulbs may have rotted. Once they've emerged, tulips can do fine in partial shade, particularly if they receive afternoon sun, but they will not thrive in full shade.

It's doubtful that you'd have success digging and moving the bulbs at this stage, but it's always worth experimenting. IF the bulbs are healthy when you examine them, try it and see what happens. But I would also consider buying some replacements.


Q: Someone said I could position a mirror to reflect sunlight on to my tulips that are planted in shade to help them emerge. Is this true? They haven't come up yet, unlike in past years when they were planted in full sun. By what date should I give up on them ever coming up?

A: Great question about positioning a mirror to reflect sunlight onto the soil where your tulips are planted! Why not experiment with that? Researchers have had some success conducting that sort of experiment with forage grasses. If your plot receives no sunlight at all, it might be difficult to reflect sun onto it. Do let us know the results of your experiment!


From: VA
George Mason Elementary School

Q: Some of our tulips have extremely short stems this year. At least the few that have already bloomed. However, some that only have the beginnings of buds have much longer stems. I know they are all the same species, so why is this true?

A: Now that's a puzzle! Temperatures during certain times in a tulip's development will affect stem length. Tulip bulbs need a certain amount of time in cold temperatures in order to release certain growth hormones. (This happens naturally during the winter.) These hormones will cause the emerging flower stems to lengthen. But if bulbs are planted too late in the fall, or experience a warm spell in winter, they may not have enough chilling time. In that case, the resulting plants may have short stems. On the other hand, a long period of cold weather before bulbs emerge in the spring can have the opposite effect: A "stressed" stem might actually grow longer. This could also happen if temperatures get very warm as the tulip plant grows. Stems that lengthen due to the stresss of too little or too much heat may not be as sturdy as stems on healthier plants. Another factor -- poor root development caused by heavy soil or lack of rain -- could result in short stems.
None of these answers your question of why only some tulips have longer stems. Take a look at your plot. Do you notice any pattern related to the location of tulips that have long or short stems? Perhaps one area of your plot has heavier soil or more shade (and cooler soil temperatures). How would you answer your own question?


From: VA
Terra Centre Elementary

Q: Our class was wondering how do tulips get their colors? How do people tell what color the bulbs are when they package them?

A: Just like you and your classmates have different hair colors, tulips growing in the wild have different petal colors. Perhaps they attract different types of pollinators. People who breed tulips for gardens also use different methods to propagate (create new) tulips with a variety of colors. Here's one method: When a breeder moves pollen from a tulip flower of one color to a tulip flower of another color, the second flower is fertilized. The seeds it produces are then planted. It will take 5 or 10 years for the tulips grown from those seeds to produce flowers. The flowers will be a new color or colors. If it's a "good" color, growers can create lots of new bulbs to sell by saving and growing the offsets (small new bulbs) that the tulips will produce each year. This is called "asexual" reproduction. It produces new plants that are exactly like the parent plants. Sometimes after a few years, the offsets from one tulip parent will naturally change color. They might even produce multi-colored offspring!

People who grow tulips commercially carefully label the plants and bulbs by type (cultivar) and color. That way, people who package them know which ones to pick out and pack!

Q: Our tulips are blooming right now. We noticed that the tips of the leaves have a red color to them. Is this because our tulips are red? Would white tulips have white around the edges of their leaves?

A: Great question and observation! If you are talking about the main tulip leaves, the red color is not likely related to the flower color. Tulip leaves actually have a red pigment in their tissues all along. But it is masked by the green chlorophyll that plants need to make food during photosynthesis. If a tulip plant is under any kind of stress, such as cold temperatures when it emerges, the chlorophyll may begin to disappear from parts of the leaves. That allows the red to show through. (The same kind of thing happens to trees in the autumn when their food-making begins to shut down for the season.)

If you are instead talking about the modified leaves that surround and protect the flower buds (called sepals), I have a different answer! As the bud stretches its tip and becomes larger, the green sepals do take on the color of the tulip flower. When it's fully open, it's hard to tell that the sepals were once green!


Q: What makes some tulips grow taller than others?

A: Just as some students in your class are taller than others, wild tulips also vary. Plant breeders can also produce tulips with different length stems.

Here are some other factors that can influence tulip height once they've been planted:
Temperatures during certain times in a tulip's development will affect stem length. Tulip bulbs need a certain amount of time in cold temperatures in order to release certain growth hormones. (This happens naturally during the winter.) These hormones will cause the emerging flower stems to lengthen. But if bulbs are planted too late in the fall, or experience a warm spell in winter, they may not have enough chilling time. In that case, the resulting plants may have short stems. On the other hand, a long period of cold weather before bulbs emerge in the spring can have the opposite effect: A "stressed" stem might actually grow longer. This could also happen if temperatures get very warm as the tulip plant grows. Stems that lengthen due to the stress of too little or too much heat may not be as sturdy as stems on healthier plants. Another factor -- poor root development caused by heavy soil or lack of rain -- could result in short stems.


From: VA
Mill Run Elementary School

Q: Why are the tops of the tulip leaves and the center sprout shriveled and brown instead of a healthy green?

A: It sounds like your early-emerging buds may have got frozen. Tulips can withstand snow and even cold temperatures. But if the flower buds have poked up, and the temperature drops to around 20 degrees F, the buds and leaves could be damaged. If that happens, blooms would not likely appear. This sometimes happens when a warm spell (which causes bulbs to emerge) is followed by a cold snap. Does that describe what happened in your garden? If not, it's possible that they may be diseased.


Q: Could the Deer and rabbit spray we have been using to keep the critters from eating the tops of our tulips, be damaging our tulips? Are there other products to keep rabbits away from the tulips that don't injure the plants?

A: It's not likely that the spray damaged your tulips. Most commercial deer and rabbit sprays are meant to be used on plants. Because you didn't describe how your students are damaged, I can't evaluate what might have happened to them.


From: The Long Eaton School - Derbyshire, Nottingham, UK

Q: "Our tulips have bloomed, they look lovely, but can anyone tell me why the tulips that we have planted over the past 3 years bloomed a lot earlier?"

A: Well, a number of factors could be at work. For instance, you might have different temperatures, sunlight, soil type, or other conditions that vary where each group of tulips is planted. Did you notice that the late-emerging tulips were in one section of your garden? If they were in the shade, they would have received less sunlight than the others. So it would have taken longer for the soil to thaw out, dry out, and warm up. If one group of tulips were in heavy, wet soil, they might also be slow to bloom.
As tulips grow in the same place over the years they develop side shoots, or bulbs. These more mature plants may tend to develop closer to the surface of the soil where it warms earlier in the season. You could test this by carefully digging some of each aged tulips and measuring how close they are to the surface.

Tulip Expert, Eve Blanchard
Science Educator and Writer

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