Cloned and Common Lilac Campaign
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Predicting leafing and flowering of cloned and common lilacs
Watch a short video on the importance of the cloned and common lilac campaign
This spring, you will receive predictions of when your  cloned ( Syringa chinensis or  common lilac   ( Syringa vulgaris)  will leaf-out and flower, an effort we call springcasting. 
These predictions will help you to more accurately capture the start of leafing and flowering on your lilacs. 
How do we do this? We use historical information about when lilacs have leafed-out and bloomed and what the weather was like preceding these events. We then use this information to develop models that can tell us, based on local weather forecasts, when lilacs are likely to leaf out and bloom this year.  Read more about these models, which are part of the  Extended Spring Indices.
What can you expect this spring?
We will send you two emails this spring - one alerting you that your lilac should be leafing out in the next three days, and one alerting you that y our lilac should bloom. Check your lilacs to see if the prediction is correct  as soon after these emails as you can,  and report your observations in Nature's Notebook .  
How do you know when you might receive the message? You might already have an idea of when your lilac usually leafs-out and blooms. Or, you can look at the maps below of the modeled leaf-out and bloom for lilacs in 2018 to get an idea of when you might first see these events on your lilacs.
2018 Lilac First Leaf: 
2018 Lilac First Leaf estimation based on historical lilac observations. Map created on the USA-NPN Visualization Tool. Visit the tool and click on your location to find out the predicted date. 
2018 Lilac First Bloom: 
2018 Lilac First Bloom estimation based on historical lilac observations. Map created on the USA-NPN Visualization Tool. Visit the tool and click on your location to find out the predicted date. 
Drs. Toby Ault and Carlos Carrillo of the Department of Earth and Atmospheric Sciences at Cornell University deliver even longer-term predictions of the start of spring. The areas in red in the map below are predicted to experience an earlier than average start to spring in 2019 and the areas in blue will experience a later than average start to spring.  
2019 long-term forecast of onset of spring, based on the Spring Leaf Index model. Map by Drs.Toby Ault and Carlos Carrillo of Cornell University.

Your reports of when you see leaf-out and flowering are much more valuable when you also report the preceding date that you didn't see those events. That means that someone looking at your data will know that there was only a short period of time in between your last "no" observation and your first "yes" - to better pinpoint the onset! 

Ideally, you should start making observations of your lilacs 2-3 times per week at least a few weeks before your lilac typically leafs and blooms. 
Why is this important?  Springcast predictions and the underlying models have value to agriculture, human health, wildland management, and more. Knowing when plants will undergo phenological changes can dramatically improve resource management and decision-making. 
The models that predict the start of spring are now being used by scientists to track how plants and animals are responding to climate change. This information is very valuable for preserving our natural resources, heritage, and way of life. 
Thank you for continuing this important legacy! 


Erin Posthumus
Outreach Coordinator