Adding a PGR (benzyladenine, a synthetic cytokinin) to nutrient media for the microclonal propagation of _M._\(\times\)_sigganteus_ produced a highly embryogenic callus, which determined the completeness of shoots and accelerated the regeneration of the plant [28]. Supplementing Murashige and Skoog (MS) medium with 0.5 mg L\({}^{-1}\) 6-benzyladenine and 0.05 mg L\({}^{-1}\) \(\alpha\)-naphthalene acetic acid in the in vitro cultivation of _Miscanthus sacchariforus_ L. had a positive effect on adventitious shoot proliferation [29]. A new, effective, and simple regeneration system for _Miscanthus sinensis_ Anders, _M._\(\times\)_sigganteus_, and _M. sacchariforus_ was developed, comprising two media supplemented exclusively with growth regulators (5.0 mg/L of 2,4-D and 0.5 mg L\({}^{-1}\) of benzyl adenine, 0.5 mg L\({}^{-1}\) of KIN and 0.5 mg L\({}^{-1}\) of naphthalene acetic acid) and lasting five months [30]. The impact of PGRs on _Miscanthus_ spp. production was mainly investigated when the plant was cultivated on regular fertile land; however, the reported results are sometimes controversial. [PERSON] and [PERSON] [31] found that while two foliar sprays of benzyl adenine at 500 or 1000 mg L\({}^{-1}\), trintexapac-ethyl at 220 mg L\({}^{-1}\), or uniconazole at 20-40 mg L\({}^{-1}\) two weeks apart controlled the height of _M. sinensis_, the benzyladenine application did not suppress the height of this plant, though it did suppress the height of the other tested ornamental grasses. At the same time, the application of trintexapac-ethyl effectively controlled the height of Poaceae grasses, including _M. sinensis_, but did not influence the filler number of any plant studied. Application of PGRs based on humic acid showed a significant increase in aboveground and underground _M._\(\times\)_sigganteus_ biomass when the crop was cultivated in fertile soil [32]. At the same time, [PERSON] et al. [33] found that the use of gibberellic acid and AB aqua rooting agent, or these two substances together, did not positively affect the rooting of _M._\(\times\)_sigganteus_ seedlings. Laboratory studies related to the effects and interactions between symbiotic fungi, represented by arbuscular mycorrhizal fungi (AMF), along with the endophyte and cytokinin-like growth regulator thidiazuron (TDZ), on _M._\(\times\)_sigganteus_ production indicated [34] that the fungal inoculants and TDZ did not influence plant growth. However, they did modulate phytohormone levels in the leaves. The study highlighted the existence of phytohormone homeostasis under the combined influence of beneficial inoculants and a growth regulator. In greenhouse and field experiments, the enhancement of _M._\(\times\)_giganteus_ productivity with beneficial soil microbes and _Ascophyllum nodosum_ L. seaweed extract was observed on poor-quality, marginal land [25], which may be associated with increased access to limited soil nutrients due to PGR application. The PGRs emitism, Agrostimulin, and Regoplant, which are based on aversecting and phytohormones produced by _Cylindrocarbon obtususculum_, were tested on _M._\(\times\)_giganteus_ cultivation in fertile soil [27] and positively impacted the physiological parameters. They increased the value of the chlorophyll ratio, particularly in the early stages of vegetation growth, and enhanced morphometric indicators of plant height, the numbers of stems in the bush, and aboveground biomass yield. In addition, the application of PGRs reduced the dependence of survival rate on weather conditions, which was particularly evident for the late planting time. A limited number of studies analyzed the impact of PGRs on _Miscanthus_ spp. development in contaminated or marginal lands, including post-military areas. In one study, treatment of _M._\(\times\)_giganteus_ rhizomes with the humic-based PGRs Gumifild Forte and Fulbital increased plant survival rates when a crop was cultivated in field conditions in previously oil-contaminated soil [35].