Spotlight on Black Locust: Leafing Up and Flowering, But Challenges Remain

Black Locust (Robinia pseudoacacia) ‘Turbo’ continues to draw interest across the Biomass Connect Demonstrator Hubs for its fast growth, nitrogen-fixing abilities, and suitability for marginal land. As of May 2025, Black Locust is in full leaf at most sites, with some even flowering for the first time — though chlorosis, deformities, and wildlife damage continue to present management challenges.

At Hillsborough, trees are fully leafed but showing signs of stress. Leaves appear very chlorotic (yellowing), and the team is observing deformed growth on new lead shoots — a recurrence of symptoms seen last year. Notably, these issues appeared after glyphosate spot spraying, suggesting a possible herbicide sensitivity. The team noted that a split-plot approach may have provided clearer insight.

At Aberystwyth, glyphosate was applied using the Herbidome applicator, and dead plant areas were cleared with a flail mower. The Black Locust trees that have survived the winter look a lot happier and healthier than the same time last year.

At Headley Hall, Black Locust is reported to be in full flush with healthy leaves. A live plant count recorded 11 dead trees, though dense foliage made exact counting difficult. The overall canopy is filling out well, indicating successful establishment for many trees.

At Cockle Park Farm, trees appear bushy and green, though some tip necrosis has been noted. Hare damage was also reported this month, reinforcing the need for ongoing wildlife monitoring.

At Auchincruive, trees are getting bushier and greener, with no specific pest or disease issues recorded.

At Boghall, trees are also looking healthy and bushy, although some branch tips are showing necrosis. The site team removed dead trees earlier in the month and applied glyphosate using both knapsack and boom sprayers to manage weeds. Inter-row mowing was completed late May, keeping growth competition under control.

At North Wyke, flowering was observed for the first time on five trees — a milestone for the site. Overall, the trees look healthy, and in areas with no gaps, canopy closure is developing well. However, clusters of buttercups remain around many tree bases, which are difficult to manage due to the prickly nature of the crop.

At Chesham, 44 Black Locust trees were confirmed alive as of 20 May, with varying levels of health. Some are thriving, while others are weaker. One tree was even spotted in bloom — a rare and encouraging sign of reproductive maturity.

While Black Locust is leafing up well and showing isolated signs of flowering, chlorosis, deformity, and herbivore pressure continue to require close attention. With its natural resilience and valuable traits, this species remains promising — but success depends on site conditions, weed control precision, and ongoing monitoring.

Spotlight on Eucalyptus: Tall Growth and Localised Damage Across the Hubs

Eucalyptus, one of the fastest-growing species in the Biomass Connect trials, is making noticeable gains in height this May — particularly in the Eucalyptus nitens and E. dalrympleana varieties. However, spring wind events and ongoing pest pressure are causing challenges at some sites, reinforcing the species’ need for careful siting and support.

At Hillsborough, E. nitens and E. dalrympleana continue to lead in growth, with E. nitens already reaching around 1.8 metres in height. Aphids remain present but are not causing significant damage. Spot-spraying with glyphosate has been effective in reducing weed pressure, and no further interventions were required this month.

At Aberystwyth, the Eucalyptus plots endured strong winds over the weekend of May 24th–25th. This caused damage to new growth at the tips of branches and led to leaf stripping — with larger-leaved species the most affected. Paths between rows have been topped, and areas close to trees mown to improve airflow and reduce grass competition.

At Headley Hall, trees have recently put on a burst of height. Frost damage has been minimal, but many leaves are turning red. Management has focused on maintaining weed control while monitoring foliage condition.

At Cockle Park Farm, Eucalyptus continues to grow well, with new growth visible across the plot. Some wind damage was reported, but no signs of hare or disease damage have been observed this season.

At Auchincruive, the outlook is mixed. Several trees still appear brown and dry — likely dead — and those that survived winter winds may require further support. Tree straps have been purchased, and extra stakes will be installed. Inter-row mowing was completed on May 26th.

At Boghall, mowing was carried out on May 21st, and new tree supports have been purchased, with installation planned as soon as possible. Eucalyptus health is under review at this site following winter damage.

At North Wyke, most trees appear healthy, though one tree that had blown over has died. Attempts to straighten wind-rocked trees have occasionally caused further damage — underlining the challenges of managing tall, fast-growing trees in exposed conditions. The last round of inter-row spraying was effective, and mowing was completed in tight rows using a ride-on mower.

At Chesham, all Eucalyptus trees were inspected and are reportedly “growing tall and looking very healthy.” No major pest or weather-related issues were noted this month.

Eucalyptus is clearly thriving at many sites, but the species’ rapid vertical growth makes it vulnerable to wind damage — particularly on exposed plots or where support is insufficient. As summer approaches, site teams will continue to monitor leaf health, support structure integrity, and aphid levels to ensure strong establishment heading into the dry season. 

Spotlight on Poplar: Rapid Growth and Full Leaf Emergence Across the Hubs

Poplar is entering the 2025 growing season with confidence, as trees across the Biomass Connect Demonstrator Hubs are now in full leaf and beginning to put on height. Whether planted as Short Rotation Coppice (SRC) or Short Rotation Forestry (SRF), Poplar continues to demonstrate rapid early growth and adaptability across a variety of UK sites — although wind exposure and weed competition remain challenges in some locations.

At Hillsborough, both SRF and SRC Poplar plots are in full leaf and putting on height. Grass beneath the trees has been mown, but the area is still awaiting a spray treatment. In the SRC plots, creeping buttercup and clover are becoming established under the canopy, which may require attention.

At Aberystwyth, inter-row mowing has been completed in both SRF and SRC plots. The trees are progressing well, and no major issues were reported this month.

At Headley Hall, Poplars are showing good growth and leaf colour. Both SRF and SRC trees are well established and leafing up uniformly.

At Cockle Park Farm, SRF and SRC Poplars are healthy, with no disease noted. Some hare damage was observed in the SRC plot, but overall development is strong. No spraying has been reported this month, but previous mowing has helped manage competing vegetation.

At Auchincruive, SRF Poplars are described as “big and blooming,” with dead trees and branches removed to make space for new growth. Inter-row mowing was completed on May 26th. In the SRC plot, leaves are growing nicely, and volunteer willows have been removed. Additional mowing is scheduled for early June.

At Boghall, SRF Poplars are looking leafy and robust. SRC Poplars are also growing well, with healthy foliage despite some wind damage noted during the month. Inter-row mowing was completed on May 21st.

At North Wyke, trees in both SRF and SRC plots are looking healthy and developing well. However, two lead stems in the SRF plot snapped — likely during high winds on May 24th. No significant disease or pest issues have been reported, and last month’s inter-row spraying was effective.

At Chesham, shiny new leaves are appearing across the SRF Poplar plot. No signs of leaf blackening were found on the AF7 variety, and although some minor bug damage was noted, it is not considered serious. The SRC Poplar plot is leafing up well and showing similar vigour.

With all Poplar plots now in full leaf and vertical growth well underway, this month has reinforced the crop’s potential as a high-yield, fast-growing component of biomass systems. While wind damage remains a risk at exposed sites, strong spring management and continued monitoring will help ensure a productive summer season.

Spotlight on Miscanthus: Strong Early Growth and Weed Management Underway

Miscanthus is powering into the 2025 growing season with visible canopy development and strong regrowth following harvest. Both Miscanthus giganteus and Miscanthus Athena are showing healthy growth across the Biomass Connect Demonstrator Hubs, while the 2023 and 2024 variety trials are progressing at varied rates, providing valuable insights into establishment success, weed competition, and environmental resilience.

At Hillsborough, no active management was reported for either main plot this month, but both M. giganteus and Miscanthus Athena are growing well, with plants reaching 60–80 cm in height. Some patches of dock, buttercup, thistle, and nettle have emerged in both plots and will likely require spot spraying or mowing soon.

At Aberystwyth, M. giganteus has grown strongly, though drought stress is becoming apparent. By mid-May, some leaves had begun to curl, and a patch of approximately 15 m² is showing significant stunting. Miscanthus Athena is generally performing well, but broadleaf weeds are appearing in bare areas and will need post-emergence herbicide treatment.

At Headley Hall, both plots are showing good new growth following harvest. M. giganteus is doing well with minimal weed presence, while Miscanthus Athena is thriving despite dry conditions. Creeping thistles have been spotted and will be sprayed before the Miscanthus gets too tall.

At Cockle Park Farm, new shoots are emerging in both plots, and no disease or pest issues have been reported. Some hare damage was observed in M. giganteus, but Athena appears unaffected. Growth is generally strong.

At Auchincruive, both plots are reported to be “growing well” and around knee-height. Post-emergence herbicide was applied on May 5th to control broadleaf weeds using a mix of Harmony SX and Starane. Results have been positive, and no pest issues were reported.

At Boghall, M. giganteus is described as “bushy, green, and healthy.” Athena is also growing well, though some bare patches remain at the lower end of the plot. Both plots were treated with the same post-emergence mix on May 7th. The treatments have worked well, though some areas may need follow-up due to persistent willow herb.

At North Wyke, growth is mixed. The section of M. giganteus that was cut and manured last year remains weak due to high grass competition. In contrast, Athena — particularly the 2023 planting — is performing better, with less weed pressure and stronger emergence. No active management was carried out in May, but observations support avoiding in-season cuts and manure applications.

At Chesham, M. giganteus and Athena were harvested in March and are now outgrowing the thistles in most areas. Weed pressure remains manageable, and growth is on track.

Variety Trials:

• 2023 Miscanthus Variety Trials:

  • At Hillsborough, replanted crops have not established well.

  • At Aberystwyth, plants are growing well, and paths have been mown.

  • At Boghall, weeds were knocked back with herbicide on May 7th, though willow herb remains an issue.

  • At North Wyke, inter-row mowing and herbicide on missed plots have helped improve conditions.

  • At Headley Hall, grass is browning off, but last year’s replants haven’t taken well.

• 2024 Miscanthus Variety Trials:

  • At Hillsborough, establishment remains poor.

  • At Aberystwyth, overwintering success is mixed, with some gaps.

  • At Boghall, plots look “weedy,” and advice is being sought.

  • At North Wyke, mowing has kept inter-rows clean.

  • At Headley Hall, browning grass and weak establishment mirror 2023 patterns.

Miscanthus is clearly on the move, with vigorous early growth and increasingly effective weed suppression in well-established plots. The variety trials continue to show how environmental conditions and planting techniques influence long-term crop success — valuable data for the future of perennial biomass systems in the UK.

Spotlight on Willow: Strong Performance at Most Hubs, but Sawfly Sets Back Aberystwyth

Willow is proving to be one of the most vigorous and resilient crops across the Biomass Connect Demonstrator Hubs this season — with tall growth, dense foliage, and strong canopy development reported at nearly every site. However, a severe outbreak of sawfly at Aberystwyth has caused significant defoliation, reminding us that pest pressure can change the picture quickly in spring.

At Aberystwyth, both the SRC plot and the Willow Variety Trial have suffered from sawfly larvae, which have stripped leaves from a large number of trees — in some cases up to 90% defoliation. While plants remain alive, this has severely impacted canopy development and delayed growth compared to other hubs.

At Hillsborough, willow is growing well in both plots, with canopies beginning to close and grass between rows mown. No pest or disease issues were noted.

At Chesham, willow is growing steadily and performing reliably. It is leafing up well with young catkins. No issues were reported, and no intervention was needed this month.

At Cockle Park Farm, willow has fully leafed out with new shoots developing. Hare damage was observed again, but no damage from disease were found.

At Headley Hall, willow is leafing out well with a healthy canopy. While some caterpillars (sawfly larvae) were observed, they are not yet causing serious damage.

At North Wyke, willow plots are growing well, There are some brown aphids on the young growth of Inger. There is no sawfly damage and Inger, that suffered last year is looking healthy. Some minor ‘black spot’ has been noted on the leaves of RR07160 and Ester. This area may benefit from inter-row mowing next visit. The inter-row spray on the missed row has worked well. Sprayed rows are starting to ‘grow out’, but the benefit can still be seen.

At Auchincruive, the willow is described as “very green and leafy” and “very tall” — a clear sign of vigorous growth. Spot spraying for dock and thistles is planned for early June, with strimming scheduled if needed. There are no current pest or disease issues.

At Boghall, willow is “green and leafy”, and inter-row mowing was completed in the variety trial on May 7th. Some pests have been noted on some trees (mostly round the outside of plot near the Miscanthus)

In summary, willow remains a standout crop in the Biomass Connect trials — offering reliable growth, early canopy development, and low management needs at most sites. However, the significant sawfly outbreak at Aberystwyth is a timely reminder of the importance of pest surveillance and rapid response, especially during warm, dry springs.

Sida (Sida hermaphrodita) is progressing well into the growing season at the Biomass Connect Demonstrator Hubs, with most sites reporting good green-up and expanding canopies. While overall health is strong, some plots are still showing patchy establishment or residual chlorosis, prompting spot-feeding, weed control, and discussions around future plot adjustments.

At Aberystwyth, plants are growing well, but there’s a clear gradient across the plot, with one end significantly ahead of the other. Yellowed plants are greening up, suggesting recovery from early stress.

Hillsborough: Leaves are coming on strong following application of a low dose of NPK fertiliser. The team also gapped up the plot, but the bottom half remains very sparse.

Chesham: Sida is growing well, with no issues reported. The crop appears healthy and is progressing as expected, with some plants reaching 1.5 m in height.

At the Headley Hall site, Sida plants are described as vigorous and green, with some plants reaching 1 metre in height. Chlorosis is still visible in parts of the plot. Some of the higher leaves on the Sida plants have started to curl up and feel crisp to the touch. possibly due to the hot, dry conditions.

Cockle Park Farm: Sida is growing well with green appearing the the rows becoming visible. Some plants show some yellowing.

North Wyke: The herbicide application has worked, but two rows were missed because of the confusing gapping-up nature of the new plant placement. These areas have been carefully strimmed. Some plants are good, some are very small, and some are missing. No plants are flowering.

At the Auchincruive demonstrator hub, the sida plants are getting bigger and greener. Inter-row spraying was completed earlier in May.

Boghall: Both rhizome and plug-propagated plants are greening up nicely.

Across the hubs, Sida is establishing well — with chlorosis fading, canopies expanding, and no pest or disease problems reported. Fertiliser and gapping-up are helping bring underperforming plots into line, while weed control remains a key focus to ensure a strong summer trajectory.

Spotlight on Reed Canary Grass: Mixed Growth and Weed Pressure Across the Hubs

Reed Canary Grass is progressing into its main growth phase across the Biomass Connect Demonstrator Hubs this May. While some sites are seeing good development and competitive stands, others are dealing with patchy establishment or significant weed grass contamination. Management has focused on targeted spraying and preparation for hand re-sowing where needed.

Aberystwyth
Reed Canary Grass is growing well, but there is lots of competition from weed grasses. Areas of the plot where RCG has failed to establish have been sprayed off and will be re-sown by hand.

Hillsborough
RCG is growing well and has reached around knee height (50–60 cm). However, the plot appears to contain multiple grass species, indicating a possible contamination or misidentification issue.

Chesham
Nothing to report.

Headley Hall
RCG is looking good, with lots of new growth and beginning to put on height. Not as thick as last year but this is down to the lack of rain so far in the season.

Cockle Park Farm
Quite good growth has been reported. No disease or wildlife damage has been observed.

North Wyke
RCG is present and competing well with other grasses. The plot border has been strimmed.

Auchincruive
The RCG plot was sprayed off on May 5th with glyphosate (4 L/ha) using both knapsack and boom sprayers. Missed patches will need to be redone.

Boghall
RCG is coming up thick and healthy. The plot was sprayed off on May 6th.

Across the sites, RCG is showing its potential for reliable establishment in wet or marginal areas — but also highlighting its sensitivity to early competition and sowing success. With further spraying and re-sowing underway where needed, plots should begin to show clearer performance as summer progresses.

Spotlight on Switchgrass: Emerging Growth and Re-establishment in Progress

Switchgrass, a warm-season C₄ grass, is known for its late emergence — and that pattern continues across the Biomass Connect hubs this May. While some sites are beginning to see green-up, others are still in the process of re-sowing or waiting for clearer signs of establishment. Weed control and plot maintenance are the main priorities at this stage of the season.

At Aberystwyth, the siwtchgrass p[plot was re-sown on May 30th with a 8-coulter drill (Coulter width of 15 cm). After sowing the plot was rolled.

At Headley Hall, the switchgrass is starting to come away from the base of the plant, but the lack of rain means there hasn’t been much growth yet.

At the Auchincruive site, the switchgrass plot was srpayed off with 4 l/ha glyphosate on May 5th.

The Boghall site had the same treatment as the AUchincruive site and was sprayed off on May 6th.

At Chesham, there has been nothjing to report from the switchgrass plot.

At North Wyke the plot borders have been strimmed and the area seems to be mostly weeds.

At Cockle Park Farm there are new switchgrass shoopts starting to appear but growth is very slow despite no damage from hares or deer and no diseases or pests.

Overall, Switchgrass is slow to start, but beginning to stir at some locations. Most teams are still focused on weed suppression and monitoring emergence, clearer establishment patterns should become visible in June.