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Cloned Lilacs


Cloned Plants Program logoYou're invited to participate in the Cloned Plants Project by purchasing a cloned lilac and reporting phenology observations via Nature's Notebook. You can also participate by tracking a common lilac that is already established in your yard. 

Why Clones?

A lilac in New York blooms later than a lilac in Virginia. Why? One way to better understand the timing of spring phenology is by planting genetically identical plants, or clones, in different locations, and then to observe when they leaf out and flower. When observations are made on cloned plants, you can know with confidence that differences in the timing of flowering and leafing between different individuals is due to differences in local environmental conditions.

Learn more »

Consider contributing to this valuable effort by tracking a cloned lilac (Syringa x chinensis 'Red Rothomagensis') in your yard. View the map to find out whether lilacs grow where you live. We are also interested in observations of cloned dogwoods; if you live in the southeastern US, a cloned dogwood might be best for you. 

See what volunteers' observations of cloned lilacs are revealing.


This spring, you will receive predictions of when your cloned lilac will leaf-out and flower, an effort we call springcasting. 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 your 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.  

These predictions will help you to more accurately capture the start of leafing and flowering on your lilacs. 

Learn more about springcasting »

How to participate...

1. Obtain your cloned plants.

Cloned lilacs are available for purchase through Jung Seed Company during the planting season (late March through early June) at a cost of $20 for two plants. Place an order from their direct page or call 1-800-247-5864.

Once you have received your plants, check the information on choosing a planting site and on lilac planting and care.

If you prefer to track plants which are already established at your site, we also welcome observations on common lilac (Syringa vulgaris)

2. Join Nature's Notebook. If you haven't already, create a Nature's Notebook account. See our specifics of observing if you need more details on getting started. Make sure you register your lilac as the clone Syringa x chinensis 'Red Rothomagensis' when adding the plant to your site. 

3. Observe your plant(s). Report what you see (yes/no/not sure) on your plant periodically following the instructions for cloned lilacs. We encourage you to observe your plant(s) 2-4 times a week, especially in the spring, when things are changing rapidly. However, we welcome any observations you can contribute.

4. Report your observations. As you collect data during the season, log in to your Nature's Notebook account and enter the observation data you recorded. You can also use our smartphone apps to submit your observations!

 2017 Results from the Cloned lilac campaign

In 2017, you reported leafing for cloned lilacs at 72 sites and flowering at 94 sites. 

How do your reports of leafing and flowering compare to last year? You reported breaking leaf buds for cloned (Red rothomagensis) several weeks earlier in 2017 than in 2016. 

Cloned and common lilac breaking leaf buds 2016-17


We see a similar pattern with your reports of flowering, which were several weeks earlier in 2017 than in 2016.

Cloned and common lilac flowering 2016-17


How do your reports compare to our predictions of leafing and flowering from the Spring Indices

Our predictions and your reports are not far off! On average, you reported leafing of cloned lilacs only 1.06 days earlier than we predicted it would occur and flowering only 3.14 days earlier than we predicted.  

For cloned lilacs, you reported leafing for 56% of your lilacs and flowering for 67% of your lilacs within 1 week of our predicted date.  

Cloned lilac vs lilac index 2017

Our predictions for leafing and flowering tended to be earlier than your reports in Southeast states and in the upper Northeast, and later than your reports in middle states such as Pennsylvania, Michigan, and Wisconsin.

Your data on cloned and common lilacs help us to understand how well our Spring Index models reflect plant activity on the ground. These results will help us to create more accurate predictions of the arrival of spring. 

Cloned plants program roots

Lilacs at NASA Goddard Space Flight Center

For over 50 years cooperators in the United States and Canada have assisted phenological researchers by making phenological observations on cloned lilacs and honeysuckles. This program has now been incorporated into the USA-NPN's Cloned Lilac Campaign. Previously it had been part of the University of Wisconsin-Milwaukee's Indicator Observation Program. In addition to the cloned and common lilac, some participants in the UWM program observed cloned honeysuckle Lonicera tatarica 'Arnold Red'. Due to its invasive nature, honeysuckles have not been distributed to observers since 1987. The USA-NPN does not distribute the honeysuckle nor support its distribution, but we do welcome observations from historically established cloned honeysuckles. Find out more about this rich legacy dataset.

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