Hair fescue is a perennial grass weed in lowbush blueberry fields that forms dense sods and reduces yield. As a result of natural tolerance or resistance of this grass to other currently registered herbicides growers rely on preemergence (PRE) applications of pronamide and postemergence (POST) applications of the Group 2 herbicides foramsulfuron and nicosulfuron + rimsulfuron for hair fescue management. This causes repeated application of Group 2 herbicides, which is compounded by the recent registration of flazasulfuron for POST suppression of hair fescue in lowbush blueberry. Mixtures of Group 2 herbicides with the amino acid–inhibiting herbicides glyphosate (Group 9) and glufosinate (Group 10), however, can improve weed control and may delay herbicide resistance development. This research used a factorial arrangement of Group 2 herbicides (none, foramsulfuron [35 g ai ha−1], nicosulfuron + rimsulfuron [13 + 13 g ai ha−1], flazasulfuron [50 g ai ha−1]) and mixtures (none, with glyphosate [902 g ae ha−1], and with glufosinate [750 g ai ha−1]) to identify possible mixtures that improve weed control and delay resistance development. Herbicides were applied in spring nonbearing year, fall bearing year, and fall nonbearing year, with each application timing conducted as a separate experiment. Foramsulfuron and nicosulfuron + rimsulfuron were not effective as fall applications, and spring applications of these herbicides with glyphosate or glufosinate improved hair fescue suppression. Glyphosate and glufosinate were more effective as fall rather than spring applications. Flazasulfuron was effective across all application timings, although its mixture with glufosinate generally improved hair fescue suppression. Flazasulfuron + glufosinate is tentatively recommended as an effective mixture for management of spring nonbearing-year and fall bearing-year hair fescue in lowbush blueberry.

Hair fescue is a common tuft-forming perennial grass weed that reduces yields and hinders mechanical harvest in lowbush blueberry fields. PRE terbacil applications traditionally controlled hair fescue but currently only provide suppression in most fields. Terbacil use has not, however, been evaluated in conjunction with other currently registered herbicides in lowbush blueberry. The objective of this research was to evaluate a range of terbacil-based herbicide treatments for hair fescue management in lowbush blueberry. The experiment was conducted at three lowbush blueberry fields in Nova Scotia, Canada. Spring nonbearing-year terbacil applications (2,000 g ai ha–1) exhibited variable efficacy on hair fescue with reduced total tuft density at one site and reduced flowering-tuft density and flowering-tuft inflorescence number at two sites. Suppression was limited to the year of application only. Terbacil followed by (fb) foramsulfuron (35 g ai ha–1) did not improve suppression. A terbacil tank mixture with glufosinate (750 ai ha–1), however, reduced flowering-tuft density and flowering-tuft inflorescence number at each site and reduced total tuft density at one site, suggesting improved suppression with terbacil + glufosinate relative to terbacil alone. Terbacil + glufosinate fb foramsulfuron gave additional reductions in total tuft density at two sites and reduced bearing-year flowering-tuft density at two sites, indicating that hair fescue suppression with this herbicide combination extends into the bearing year. Although less effective than the industry standard pronamide applications, terbacil + glufosinate or terbacil + glufosinate fb foramsulfuron could be used as part of a weed management program for hair fescue in lowbush blueberry.

There is a continual need for invasive plant science to develop approaches for cost-effectively benefiting native over nonnative species in dynamic management and biophysical contexts, including within predominantly nonnative plant landscapes containing only small patches of native plants. Our objective was to test the effectiveness of a minimal-input strategy for enlarging native species patches within a nonnative plant matrix. In Pecos National Historical Park, New Mexico, USA, we identified 40 native perennial grass patches within a matrix of the nonnative annual forb kochia [Bassia scoparia (L.) A.J. Scott]. We mechanically cut B. scoparia in a 2-m-wide ring surrounding the perimeters of half the native grass patches (with the other half as uncut controls) and measured change in native grass patch size (relative to pretreatment) for 3 yr. Native grass patches around which B. scoparia was cut grew quickly the first posttreatment year and by the third year had increased in size four times more than control patches. Treated native grass patches expanded by an average of 25 m2, from 4 m2 in October 2015 before treatment to 29 m2 in October 2018. The experiment occurred during a dry period, conditions that should favor B. scoparia and contraction of the native grasses, suggesting that the observed increase in native grasses occurred despite suboptimal climatic conditions. Strategically treating around native patches to enlarge them over time showed promise as a minimal-input technique for increasing the proportion of the landscape dominated by native plants.

Hair fescue is a widespread, seed-limited perennial grass in lowbush blueberry fields. Growers rely on pronamide, an expensive and difficult herbicide to use, for hair fescue management. Recent herbicide registrations provide opportunity to reduce pronamide use, though effects of these herbicides on hair fescue suppression and seedbank reduction are not well understood. The objectives of this research were to determine (1) the effects of herbicides currently registered in lowbush blueberry on suppression of hair fescue tufts and (2) whether suppression of hair fescue with these herbicides reduces hair fescue seedbanks. Pronamide gave the most consistent reductions in flowering tuft density, though applications after both autumn pruning and autumn of the nonbearing year were required to reduce the hair fescue seedbank by >60% across sites. Nonbearing-year hexazinone applications did not control hair fescue or reduce the seedbank. Nonbearing-year terbacil applications reduced flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. Glufosinate applications following autumn pruning or in the spring of the nonbearing year did not suppress hair fescue or reduce the seedbank. Spring nonbearing-year foramsulfuron applications, alone or after autumn or spring glufosinate applications, reduced hair fescue flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. In contrast, autumn and spring glufosinate applications followed by spring nonbearing-year foramsulfuron applications, when combined with autumn nonbearing-year pronamide applications, reduced flowering tuft density in both the nonbearing and bearing years and reduced the hair fescue seedbank by 58% to 83% across sites. Results indicate that hair fescue seedbanks can be reduced in lowbush blueberry fields and that a reduction in pronamide use will require alternative bearing-year treatments to prevent tuft recovery and seed production.

This study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

Quackgrass is a problematic agricultural weed in the temperate zones of the world and is difficult to control without herbicides or intensive tillage. However, it may be possible to control quackgrass with less environmental impact by combining multiple low-intensity control methods. A pot experiment was conducted in July to October 2012 and repeated in June to September 2013 to investigate the effect of rhizome fragmentation, competition from white clover, shoot-cutting frequency, and cutting height on quackgrass. Rhizome fragmentation was expected to result in more, but weaker, quackgrass shoots that would be more vulnerable to shoot cutting and competition. However, by 20 d past planting, rhizome fragmentation did not change the total number of quackgrass shoots per pot, because an increase in main shoots was offset by a decrease in tiller numbers. Rhizome fragmentation did not reduce quackgrass biomass acquisition during the experimental period. Although rhizome fragmentation did reduce total fructan content, it did not enhance the effect of clover competition, shoot-cutting frequency, or shoot-cutting height. Clover competition by itself reduced quackgrass shoot numbers by 72%, rhizome biomass by 81%, and belowground fructan concentration by 10 percentage points, compared with no competition. The more frequently quackgrass shoots were cut, the less biomass quackgrass acquired, and a high shoot-cutting frequency (each time quackgrass reached 2 leaves) resulted in a lower belowground fructan concentration than a low shoot-cutting frequency (at 8 leaves). However, in pots without competition, a higher shoot-cutting frequency resulted in more quackgrass shoots. A lower shoot-cutting height (25 mm) had more impact when shoot cutting was more frequent. In conclusion, rhizome fragmentation did not reduce the number of quackgrass shoots or rhizome biomass, but competition from white clover, a high shoot-cutting frequency, and a low shoot-cutting height strongly suppressed quackgrass biomass and fructan acquisition.

All herbicide treatments controlled the initial stand of Canada thistle [Cirsium arvense (L.) Scop.] and musk thistle (Carduus nutans L.) on a subirrigated range site. Annual retreatment controlled seedlings and the few plants that emerged from surviving root remnants after the first application. Average perennial grass production on unfertilized, herbicide-treated plots increased 110, 314, and 212%/yr over unfertilized check plots during the 3-yr period of treatment, i.e., 960, 3450, and 4300 kg/ha, respectively. Grasses did not fully reoccupy the site at the end of 3 consecutive yr of excellent thistle and forb control. The increase in grass production varied considerably among several herbicide treatments that controlled thistles equally. Grass production in the third year was greater under the 3,6-dichloropicolinic acid and 2,4-D [(2,4-dichlorophenoxy)acetic acid] treatment series than all other treatments. Ammonium nitrate enhanced the recovery of grass damaged by certain herbicides, but favored the competitive ability of the thistle more than that of the grasses.

Field experiments were conducted in 1992 and 1993 to evaluate wirestem muhly control in no-till corn with application of glyphosate, nicosulfuron, and primisulfuron. Glyphosate was applied preplant at 1.1 kg ai/ha. Nicosulfuron and primisulfuron were applied at 0.018, 0.036, and 0.072 kg ai/ha and 0.020, 0.040, and 0.080 kg ai/ha, respectively, at four postemergence timings that included a split application. Similar experiments were conducted with wirestem muhly grown from rhizomes and seed in the greenhouse. Glyphosate was the most effective herbicide in the greenhouse, providing at least 96% control. However, preplant application of glyphosate in the field was ineffective in controlling wirestem muhly. On average, nicosulfuron and primisulfuron never exceeded 72% control of wirestem muhly in the greenhouse or in the field. Nicosulfuron was generally more effective than primisulfuron. Control with split application timings was more uniform over a 12-wk period than single applications and late postemergence applications were often too slow acting to affect wirestem muhly growth. Although neither nicosulfuron nor primisulfuron controls wirestem muhly, both can provide suppression of this weed where other alternatives do not exist.

Field experiments were established in 1978 and repeated in 1979 to monitor quackgrass [Agropyron repens (L.) Beauv. ♯3 AGRRE] rhizome growth through a growing season. Quackgrass shoots grew most vigorously when temperatures were moderate. They elongated and differentiated an inflorescence in June. Rhizome apical tips remained belowground in late spring, early summer, and early fall. Quackgrass rhizome tips grew vertically and emerged from the soil in midsummer and late fall. Experiments conducted in growth chambers revealed that photoperiod, temperature, and nitrogen level affected quackgrass shoot and rhizome growth. Shoots grew vigorously at 21C and elongated to differentiate an inflorescence when exposed to a photoperiod of 14 h or longer. Rhizome apical tips remained belowground when plants were grown at 21 C and received 16 or 12 h of light, but the tips curved upward and emerged from the soil when quackgrass was grown at 32 or 10 C, or when the plants received 14 or less than 10 h of light. The temperature and photoperiod responses coordinated to partition the growing season into primary rhizome and rhizome-tiller growth periods.

Greenhouse and field experiments (at Rosemount and Roseau, Minnesota) were conducted to characterize the growth and development of 10 quackgrass [Agropyron repens (L.) Beauv.] biotypes selected near Roseau, Minnesota. The biotypes were highly variable for all traits studied. Eight of the biotypes had flag leaves approximately 1 cm wide, but two biotypes had flag leaves approximately 1.5 cm wide. Four biotypes were glaucous and blue-green in color, and the other biotypes varied from light to dark green and had varying leaf pubescence. In the field, plant height varied from 59 to 79 cm, and rhizome length varied from 105 to 135 cm. Spike production varied from 4 to 62 spikes per plant, and mid-season rhizome bud production varied from 246 to 1,211 buds, suggesting that the biotypes varied in their reproductive potential. Shoot dry weight varied from 48 to 362 g per plant, and daughter shoot production varied from 7 to 235 shoots per plant. The quackgrass near Roseau, Minnesota, appears to be made up of several distinct biotypes.

Various chemical and cultural treatments were evaluated for smutgrass [Sporobolus poiretii (R.&S.) Hitchc], control and their effects on pangolagrass (Digitaria decumbens Stent.) and bahiagrass (Paspalum notatum Flügge). Herbicide treatments were dalapon (2,2-dichloropropionic acid) at 1.7, 3.3, and 5.0 kg/ha with Sunoco HE spraying oil at 0, 9.4, 19.0 and 37.0 L/ha. Five weeks after herbicide treatment plots were clipped (clipped vs. nonclipped) and fertilized (0 vs. 112 kg/ha N). Increasing dalapon from 1.7 to 5.0 kg/ha increased smutgrass control and decreased the number of smutgrass plants/plot. Pangolagrass ground cover generally increased with fertilization, as the rate of dalapon increased up to 3.9 kg/ha. Bahiagrass ground cover decreased with rates of dalapon above 1.7 kg/ha. Increasing the rate of oil increased bahiagrass ground cover after 90 days. Nitrogen applied 5 weeks after dalapon treatment and semi-annually for 5 yr generally decreased ground cover of smutgrass and bahiagrass, but increased pangolagrass. Clipping treated smutgrass plants increased pangolagrass and bahiagrass ground cover while decreasing the ground cover of smutgrass.

Greenhouse and field experiments were conducted to evaluate the effectiveness of nicosulfuron and primisulfuron with different adjuvants on wirestem muhly control. The adjuvants evaluated with the two herbicides included a nonionic surfactant, crop-oil concentrate, crop-oil concentrate plus urea-ammonium nitrate, methylated vegetable-oil concentrate, and organosilicone methylated vegetable-oil concentrate. In the greenhouse, nicosulfuron and primisulfuron performance was similar, although small differences occurred between adjuvants and herbicides. In the field, changing adjuvant affected nicosulfuron performance more than primisulfuron and in general, greater control was achieved with nicosulfuron than with primisulfuron. Among adjuvants, methylated vegetable-oil concentrate provided greater wirestem muhly control with nicosulfuron and sometimes primisulfuron compared to the others, while the nonionic surfactant was the least effective with both herbicides. Regardless of adjuvant, none of the field-applied treatments controlled wirestem muhly much beyond the 12 wk-evaluation period.

Four field experiments were conducted during 1988 and 1989 to determine the effects of POST application of nicosulfuron on quackgrass control in conventional field corn. A single application of nicosulfuron at 35 to 70 g ha–1 applied to four- to six-leaf quackgrass controlled over 90% of quackgrass five weeks after treatment. Nicosulfuron at 35 g ha–1 applied at the one- to three-leaf stage was not as effective as the same rate applied at the four- to six-leaf stage. When nicosulfuron at 35 g ha–1 was applied to four- to six-leaf quackgrass, over 80% of the quackgrass regrowth was controlled one year later. Nicosulfuron did not injure ‘Agway 584S’ corn at the highest rate (140 g ha–1) tested and did not reduce silage or grain yield.

Under greenhouse conditions, approximately 50% visible control of bermudagrass [Cynodon dactylon (L.) Pers. ♯3 CYNDA], quackgrass [Agropyron repens (L.) Beauv. ♯ AGRRE], and wirestem muhly (Muhlenbergia frondosa L. ♯ MUHFR) was obtained using 0.56 kg/ha glyphosate [N-(phosphonomethyl)glycine], CGA-82725 {2-propynyl-2-[4-([3,5-dichloro-2-pyridinyl] oxy) oxy)phenoxy propanoate}, 0.28 kg/ha fluazifop-butyl {(±)-butyl 2-[4-[(5-(trifluoromethyl)-2-pyridinyl)oxy] phenoxy] propanoate}, sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one}, and 0.11 kg/ha haloxyfop-methyl [methyl 2-(4-((3-chloro-5-(trifluoromethyl)-2-pyridinyl)oxy)phenoxy)propanoate]. Except for quackgrass, sethoxydim and fluazifop-butyl reduced shoot regrowth in plants clipped 3 to 6 h after treatment Sethoxydim required a 24-h duration on quackgrass foliage to reduce growth. Fresh weights of haloxyfop-methyl- and CGA-82725-treated plants required a 12- to 24-h clipping for reduced regrowth in all species. For all herbicides and species tested, little or no regrowth occurred when plants were clipped 48 h after treatment. A 1-h interval between split applications of sethoxydim and a 24-h interval between split applications of fluazifop-butyl and haloxyfop-methyl reduced fresh weights of bermudagrass regrowth when compared to an equivalent single rate. Regrowth of treated quackgrass indicated a 24-h interval was required for reductions with split applications of sethoxydim, fluazifop-butyl, and haloxyfop-methyl. Wirestem muhly regrowth was reduced after a 1-h interval between applications. In all species, superior control was obtained using two half-rate applications compared to one full-rate application.

Sheep and hair fescue are perennial, tuft forming grasses that spread by seed and form dense sods in wild blueberry fields. These sods compete with the crop for resources and hinder harvest. Field and greenhouse studies were conducted in 2015 to evaluate 1) the effect of sequential glufosinate and foramsulfuron applications on suppression of fescues in the greenhouse and field, and 2) efficacy of glufosinate and foramsulfuron on fescue seedlings when applied at 2, 4, 6, and 8 wk after seedling emergence in the greenhouse. Glufosinate applications at 750 and 1,005 g ai ha−1 followed by foramsulfuron application at 35 g ai ha−1 reduced fescue leaf number and biomass relative to foramsulfuron application alone in the greenhouse. In the field study, fescue flowering tuft density, tuft inflorescence height, seed production, and seed viability were reduced by foramsulfuron alone, but there was a trend towards lower seed production and tuft height when fescues were treated with glufosinate at 1,005 g ha−1 followed by foramsulfuron. Foramsulfuron caused low seedling mortality at all application timings evaluated, but glufosinate caused >90% mortality in seedlings when applied at 2, 4, 6, or 8 wk after seedling emergence. Our results suggest that sequential applications of these herbicides are less effective under field conditions relative to results obtained in the greenhouse, though burndown glufosinate applications may have a role in reducing fescue seedling recruitment. Additional research should be conducted to determine the effect of early spring and autumn glufosinate applications on fescue seedling recruitment and suppression of established fescue tufts with subsequent foramsulfuron applications.

The competitive ability of five cool-season grasses relative to Dalmatian toadflax, musk thistle, and downy brome was assessed in two field studies. In 1994, Bozoisky Russian wildrye and four wheatgrass varieties (Critana thickspike, Hycrest crested, Luna pubescent, and Sodar streambank wheatgrass) were seeded into populations of downy brome and musk thistle at Riverside, WY. The same grasses were seeded into populations of Dalmatian toadflax at Cheyenne, WY, in 1995. In 1997 and 1998, weed populations at both study sites were reduced in areas seeded with the five grasses relative to unseeded controls. Hycrest crested and Luna pubescent wheatgrasses were the most competitive against the three weed species. Bozoisky Russian wildrye was more competitive against Dalmatian toadflax than against the other weeds. Sodar streambank wheatgrass suppressed musk thistle and downy brome but was not competitive against Dalmatian toadflax. Seeded grasses, such as Hycrest crested and Luna pubescent wheatgrass, appeared to limit the re-establishment of these weeds. Economic model predictions of the net present values and the internal rates of return suggest that Hycrest crested and Luna pubescent wheatgrass can provide financially feasible long-term weed control only if desired grass yields are maintained for more than 15 yr.

Jubatagrass is one of the most invasive plants along the California and southern Oregon coast. It establishes dense populations that can severely impact native plant diversity and conifer seedling recruitment following forestry operations. This goal of this study was to evaluate the effectiveness of both manual removal and several herbicide control options and application techniques. In addition, a cost analysis was also conducted for the most successful herbicide control methods. Results demonstrate that mechanical removal through digging is effective, although labor intensive. Among the herbicides tested, glyphosate applied as a high-volume (spray-to-wet) application (0.6% ae) in early summer, low-volume application (2.4% ae) in early summer or fall, and ropewick technique in early summer or fall (> 9.9% ae) all provided ≥ 88% jubatagrass control, but the low-volume treatments were the most cost effective. Although the graminicide sethoxydim at the highest rate (0.36% ai) did not give effective control, fluazifop applied in the fall in a low-volume treatment (0.98% ai) gave 87% control of jubatagrass. Imazapyr gave some level of control but does not appear to provide an economical option for jubatagrass management. Results of this study demonstrate that in addition to the more conventional methods of mechanical removal and spray-to-wet glyphosate (0.6% ae), control of jubatagrass can also be equally or more effective with low-volume and ropewick applications of glyphosate.

Rice was planted at 78 kg/ha with different densities of creeping rivergrass. Creeping rivergrass at stand densities (SD) of 10,000 to 70,000 stolon segments/ha produced 5.4 to 6 stolons per introduced segment; however, 130,000 through 520,000 SD produced 1.4 to 2.1 stolons per segment. Stolon production was 60,000 plants/ha and increased to 760,000 stolons/ha at planting densities of 10,000 to 520,000/ha, respectively. The 260,000 and 520,000 SD produced similar stolon lengths of 217 and 318 km/ha; however, stolon length was less at lower SD. Total node production was 290,000 nodes per ha with an average of 29 nodes per segment in the 10,000 SD and 5.4 to 9.8 nodes per segment with 70,000 or greater SD. Total biomass increased as SD increased. Creeping rivergrass shoot emergence from soil was 31, 63, 44, and 25% for segments planted at 0, 1.3, 2.5, and 5 cm deep, respectively. In a greenhouse study, glyphosate at 1,260 g ai/ha controlled creeping rivergrass 91% and biomass production was 19% of the nontreated creeping rivergrass. Bispyribac, cyhalofop, fenoxaprop/s, fenoxaprop/s plus fenoxaprop, glufosinate, imazethapyr, penoxsulam, propanil, and quinclorac were less effective than glyphosate.

Studies were conducted to evaluate growth and reproductive capabilities of creeping rivergrass in response to rice herbicide programs. Creeping rivergrass grown from single-node stolon segments, multiple-node stolon segments, and rhizomes was treated with various herbicides to evaluate activity on subsequent growth and viability of nodes produced from treated plants. Comparison with the nontreated, cyhalofop, glyphosate, and imazethapyr reduced creeping rivergrass fresh weight by more than 84 to 96%. Glyphosate reduced sprouting of nodes from treated plants 93% compared with nontreated plants. Activity from these herbicides may decrease when applied to plants grown from rhizomes versus rhizome clusters. Plants treated with cyhalofop, glyphosate, and imazethapyr had reduced fresh weight of 36 to 46% when plants were grown from a rhizome cluster, and 69 to 90% when plants were grown from a single rhizome segment, compared with nontreated. Cyhalofop and glyphosate reduced node sprouting by 81 to 98% of nontreated, regardless of parent structure.

Miscanthus × giganteus cv. Illinois is a high-yielding perennial grass crop being developed for cellulosic biomass production in the United States. It is a sterile cultivar and must be established using plantlets or rhizomes; this asexual propagation is relatively expensive, thereby limiting more widespread acceptance. Perennial, tetraploid, seeded types of M. × giganteus have been developed that could reduce establishment costs, while producing high biomass yields. Weed control during the year of establishment is essential because this grass crop does not compete well with weeds in the establishment year. Greenhouse and field experiments were conducted to identify PRE and POST herbicides that would not adversely affect seeded M. × giganteus emergence or growth. Imazethapyr and quinclorac applied PRE had no negative affect on M. × giganteus growth in the greenhouse with respect to seedling emergence, plant height, observed injury symptoms, or fresh weight. In the field, plant emergence was significantly higher with quinclorac plus atrazine than the nontreated control, and emergence with isoxaflutole plus atrazine was not significantly different from the control. Six herbicides applied POST in the greenhouse showed little or no negative effect on miscanthus growth. In the field, several PRE plus POST herbicide combinations did not negatively affect M. × giganteus growth; however, none of these provided adequate weed control under irrigated conditions. Further evaluation of PRE and POST herbicides is needed to identify robust weed control options that are safe on seeded M. × giganteus.