German term (edited): Kulturnutzung 3 - 4 Jahre

This seems to be a term used in Austria:
http://www.biogarten-noe.at/?product=liebstoeckl
https://www.reinsaat.at/shop/DE/culinary_herbs/lovage_-_levi...

http://www.herbs2000.com/herbs/herbs_lovage.htm
"Normally lovage plants have a comparatively long life and can survive for eight years. However, it would not be wise to grow any plant of the species in your garden for this long as they loose vigor with age. It is best if you split the plants and re-plant the plump roots along with the stems at intervals of three to four years. This helps the plants to remain strong and energetic. The best time of the year to undertake this work is either during the setting of spring or the latter part of fall. During both these periods the plant remains dormant and hence unlikely to cause any harm to the existing plants."

Divide perennials every 3-4 years for more productive plants: http://pioneerthinking.com/divide-your-perennials

From a seed packet for Thymian: "Pflege: ... alle 2 bis 3 Jahre durch Teilung verjüngen"

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Note added at 4 hrs (2017-07-13 10:14:13 GMT)
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For lovage, http://modernfarmer.com/2016/03/lovage/
"Effective life: A decade or even longer, if roots are divided and replanted every four years"