Lacy phacelia (Phacelia tanacetifolia Benth.), a plant of North American origin, has been cultivated in the Carpathian Basin since the end of the 19th century. It was sown for ornamental purposes, but at the same time its potential for beekeeping was also recognized. It was prophesied to save the future of the Hungarian apiculture, but in the period following the Second World War with the collapse of the large estate system, it was cultivated as a bee pasture only on a small scale. Since the beginning of the 20th century, Hungarian researchers have been studied its forage potential in several experiments. Despite the fi rst contradictory conclusions, it has been respected as a valuable forage crop for several livestock species since the 1970s. Its excellent potential for green manuring and soil disinfection has been also confi rmed in many experiments carried out in the Carpathian Basin for more than a century. Since the end of the 1970s, its exportoriented seed production has boomed both in small and large farms in the Little Hungarian Plain (in NW Hungary). Th is practice has been strongly linked to migratory beekeeping, which has elevated lacy phacelia to the most important melliferous plants producing monofl oral honey in Hungary. Its annual production area has fl uctuated between 1500 and 11,000 ha in the last 20 years.

Phacelia tanacetifolia, an excellent cover, green manure and honey crop is now widely cultivated throughout the world. One of its principal European seed production regions is north‐western Hungary, where the recent withdrawal of a potent herbicide, linuron, created a new challenge for many growers. The goal of this study is to identify the main factors determining weed species composition in the phacelia fields of the region and to assess the efficiency of tine harrow and clopyralid herbicide in reducing weed abundance and biomass. We carried out a series of weed surveys across the study region following a two‐level design: (i) we estimated the cover of all weed species in 205 fields (broad‐scale survey, BS); and (ii) in 22 of these fields, we provided more precise biomass measurements (counting the individuals and measuring the dry weights of all weed species) in microplots samples (fine‐scale survey; FS). To characterize the fields, 34 background variables were also collected for all of the studied fields. In both investigations, Chenopodium album was by far the most abundant weed. Within the BS, using a minimal adequate model containing 11 terms with significant net effects, 20.93% of the total variation in weed species data could be explained. The variation in species composition was determined by environmental factors (soil pH, clay and K; precipitation and temperature), non‐chemical management variables (crop cover, preceding crop, irrigation and tillage system) and herbicides (linuron and clopyralid). Variation partitioning demonstrated the dominance of environmental and cultural components in shaping the weed species composition. Although the effect of mechanical treatments was most likely masked in the BS by the soil properties, our FS suggests that tine harrow could efficiently decrease the total number and biomass of weeds and can be a useful tool in the phacelia management of the future.

Stachys annua (L.) L., a melliferous archaeophyte plant became a dominant weed of the cereal stubbles of the Carpathian Basin in the medieval three-field system. By the middle of the nineteenth century, this plant provided more than two-thirds of the Hungarian honey production, and its high quality monofloral honey turned into a characteristic brand of the Hungarian apiculture. Recognizing its importance, S. annua also briefly became a minor crop cultivated in “bee gardens” and arable fields in the late nineteenth century, possibly also in response to the first signs of its upcoming decline. Starting with the advent of the steam plough, the twentieth century has brought a drastic decline for S. annua due to a combination of deeper and earlier tillage operations, agrochemicals, and new competing weed species (in particular the common ragweed, Ambrosia artemisiifolia). The last remnant stands of this previously dominant weed species are of considerable ecological and historical value as farmland biodiversity hotspots. These sites are important refuge for rare weeds, wild pollinators (including bumblebees), and declining farmland birds, which could be targeted by eco-schemes under the European Union’s (EU’s) greening Common Agricultural Policy. The rediscovery of the cropping potential of S. annua and the development of an appropriate technology would also allow its cultivation as a valuable bee forage, catch crop, green cover, or oilseed plant in the future.

Stachys annua (L.) L.– a typical annual weed species in stubble fields – was the most important melliferous plant in the Carpathian Basin during the 19th century. The agricultural intensification led to a drastic decline in the species, and previous efforts for its cultivation were unsuccessful due to its unevenly germinating seeds. This study aims to identify an effective method for overcoming the primary seed dormancy of S. annua. In laboratory experiments, we evaluated the effects of moist stratification for 4 weeks (in cold/warm sand) as well as using a gibberellic acid (GA) solution (250 mg/L) on seed germination under two light-temperature regimes (a “constant” regime at 20°C in continuous darkness, and a “fluctuating” regime with 14 h light at 20°C followed by 10 h dark at 10°C). Our results indicate that freshly matured seeds were mostly dormant at maturity. Gibberellic acid has a substantial role in breaking seed dormancy and can help substitute for the cold requirement. The best combination consisted of a GA treatment following a short (4 weeks) warm stratification, which led to a high (98%) germination rate in darkness at 20°C. The results indicate that, under natural circumstances, the seeds of S. annua require a longer period for their primary dormancy to be released. Our findings can establish the basis for the development of a dormancy-breaking technology to achieve uniform germination allowing future cultivation of the plant in bee gardens and arable fields.