Journey North International Plant Study

Vertically Challenged Tulip Plants: The Tulip Expert Responds

What’s going on with the tulips in Seattle?
We asked CQ #10: “Lafayette Elementary school’s tulips were stunted in height this year. What factors might have caused their tulip plants and tulips in the whole Seattle area to be shorter this spring? Can you think of other examples?"

Mrs. Huter's 4th Graders from Council, ID responded, "I think that it was colder in Seattle this year and that is why the tulips are not so tall," wrote one student in our class.
Mrs. Huter's class then discussed the situation in Seattle, "We know Seattle had
much more rain this year. Perhaps the lack of sunlight kept the tulips from growing so tall."

Eve Blanchard

Eve Blanchard, the Journey North Tulip Expert shows us the thinking process that a scientist might go through.
Here's what she says:

Good thinking, Lafayette students. Yes, a drastic change in weather can cause tulips to be stunted. (They are a bit more temperature-sensitive than daffodils and other spring bulbs.) This often happens when a warm spell is followed by a cold snap. When I looked at this 3-month graph of temperature departures in your area, I saw some real interesting patterns!

Daily Temperature Departures for Seattle area Jan.-Mar.2006

Your warm January weather (or a warmer winter in general) could also break your bulbs’ “dormancy” too early. Most tulips need 12 to 16 weeks of underground chilling in order to grow and bloom well. But it sounds like you have beautiful blooms, so I’m sticking with my theory that temperature fluctuations were to blame.

If you had told us that only your tulips were stunted, but not tulips elsewhere in the neighborhood, I might have made one of these conclusions: 1) you planted them too late, so they weren’t chilled long enough or 2) they were in soil that was overly compacted or wet.

So, you see, even “experts” have to consider the data and try to come up with explanations that seem to fit. No one knows all the answers. That’s what is so exciting about science!