USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Cloned Plants Project

Cloned Plants Program logoWe invite you to participate in the Cloned Plants Project, by purchasing a cloned common lilac or flowering dogwood and making observations on it through Nature's Notebook.

Why Clones?

A maple tree in New York blooms later than a maple tree in Georgia. Why? Is it that both trees bloom when it's been warmer than 40 degrees farenheit for 3 weeks? Or are there genetic differences between the trees, which have optimized each one for spring in different climates? One way to tease apart genetic and environmental responses is to make observations on cloned  plants. When researchers can take data from genetically identical plants across the country, they can better detect the climate change signal - without all the noise created by genetic variation. Explore the many valuable findings and publications using the data from this project.

Lilacs and Dogwoods

Currently the USA-NPN's phenology observation program, Nature's Notebook supports observations of two species of cloned plants, a lilac (Syringa x chinensis 'Red Rothomagensis') and a dogwood (Cornus florida 'Appalachian Spring'). See the map to find out whether lilacs or dogwoods would be most appropriate where you live. You may also observe the common lilac (Syringa vulgaris) as part of this program - although it is not a clone, it does tend to have a uniform response to climate.


Through our collaboration withLilac phenophases photo collage.  Photo credit: Mark Schwartz Jung Seed Company, cloned lilacs are now available for purchase. Orders can be placed through Jung’s web page or by calling their order department at 1-800-247-5864. Once you have received your cloned lilac, check the information on selecting a planting site and on planting and care of the lilac.

Cloned dogwoods are currently only available through a wholesale nursery, and are purchased for a limited number of observers by the USA-NPN. If you live in the southeast, and would like to observe a dogwood, please select 'yes' to the "Request for Dogwood" field when you register or edit your account on our website. Once you have received your cloned dogwood, check the instructions planting and care of the dogwood.


Lilac and dogwood phenology is observed and recorded using the same methods described on the How to Observe pages and the species profile pages.

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 Plants Project. 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 obsrved cloned honeysuckle Lonicera tatarica 'Arnold Red'. Due to their invasive nature, honeysuckles have not been distributed to observers since 1987. The USA-NPN does not distribute the honeysuckle nor support their distribution. The USA-NPN does accept observations from historically established cloned honeysuckles.Find out more about the Cloned Plants Project and its history.