The Red Rothomagensis (Chinese) lilac is a perennial, deciduous shrub that grows 12 to 16 feet tall. Its tiny, reddish-purple flowers are grouped into showy, fragrant, terminal, long clusters. Compared to the much broader leaves of the common lilac (Image showing the lilac leaf difference), these leaves are about twice as long as they are wide.
The Red Rothomagensis (Chinese) lilac is a cloned plant grown as an ornamental. The most authoritative source identifies it as a cross between Syringa laciniata and Syringa vulgaris. The clone used for the USA-NPN Cloned Plants Project is properly known as Syringa x chinensis ‘Red Rothomagensis,' sometimes referred to incorrectly as ‘Persian Lilac.' Although introduced, cloned lilacs are not invasive. The USA-NPN Red Rothomagensis cloned lilac also does not produce seeds.
This cloned plant is genetically identical to all other cloned lilac plants in the USA-NPN Cloned Plants Project. We monitor these cloned lilacs to understand how they might respond to climate without the effects of variation among plants. These cloned lilacs were previously distributed as part of historic phenology networks in the United States. Observers who monitor cloned lilacs from the historic projects can now enter their observations as part of the USA-NPN.
These cloned lilacs can be obtained for planting and subsequent observation as part of the USA-NPN. 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. If you have recently obtained a cloned lilac plant, please check the information on how to select a planting site and the instructions for planting and care of your cloned lilac.
When to start observations: In the middle of winter, lilac buds are desiccated (dried out) and appear somewhat shriveled (mid-winter bud). In late winter, after conditions begin to warm, the buds hydrate (swell due to becoming moist), and the tips open slightly (late winter bud). When these two events happen, you can start to look for the first emerging leaves (daily observations). Once the buds have swelled and the bud ends are slightly open and a bit green, the next round of warm weather can force the first leaves to emerge.
We wish to thank Joseph Caprio, Pierre Dubé, Charles Holetich, William Kennard, Helmut Lieth, Leonard Perry, Owen Rogers, Forest Stearns, Morrie Vittum, Robert Wakefield, and all the original researchers involved in regional phenology projects throughout the United States and Canada. Their foresight in establishing these phenological observation programs will provide an abundant harvest of knowledge to this and future generations. The instructions and information provided on this web page are derived from those presented in a previous publication (Dubé et al. 1984).
Do you see...?
Breaking leaf buds Image of Breaking leaf buds In at least 3 locations on the plant, a breaking leaf bud is visible. A leaf bud is considered "breaking" once the widest part of the newly emerging leaf has grown beyond the ends of its opening winter bud scales, but before it has fully emerged to expose the leaf stalk (petiole) or leaf base. The leaf is distinguished by its prominent midrib and veins. (This phenophase was previously called "First leaf".)
All leaf buds broken Image of All leaf buds broken For the whole plant, the widest part of a new leaf has emerged from virtually all (95-100%) of the actively growing leaf buds. (This phenophase was previously called "Full leaf out".)
Open flowers Image of Open flowers For the whole plant, at least half (50%) of the flower clusters have at least one open fresh flower. The lilac flower cluster is a grouping of many, small individual flowers. (This phenophase was previously called "First bloom".)
Full flowering Image of Full flowering For the whole plant, virtually all (95-100%) of the flower clusters no longer have any unopened flowers, but many of the flowers are still fresh and have not withered. (This phenophase was previously called "Full bloom".)
End of flowering For the whole plant, virtually all (95-100%) of the flowers have withered or dried up and the floral display has ended. (This phenophase was previously called "Last bloom".)