Adapting to Rising Soil Moisture Deficits in Field Tree Production
Met Éireann Soil moisture deficits July 8th from left to right: well-drained, moderately drained, and poorly drained soils.
With Met Éireann’s maps showing Soil Moisture Deficits (SMDs) surpassing 50 mm to 69 mm across the south and east, field nursery conditions are turning critical. While deep-rooted semi-mature trees can tolerate early dryness, young tree seedlings and 1+1 whips are facing immediate growth restrictions.
Nutrients need to be available to the trees two weeks before the “Lamas growth” (start of August), leaving little room for application without irrigation. With no rain forecast in the east of the country in the coming week, nurseries need to adapt their fertiliser strategy immediately:
- Halt Granular Nitrogen: Do not top-dress dry soils. Without >10 mm of rain, nitrogen will volatilize (Nitrous oxide gas is a highly potent greenhouse gas). Worse, idle nitrogen will trigger a dangerous, soft vegetative flush if/when rains arrive in late July or August, leaving trees highly vulnerable to frost damage.
- Prioritise Potassium (K): If applying nutrients to irrigated blocks, utilise high-K compound fertilisers. Potassium regulates stomatal closure, helping trees manage internal water balance and stress.
- Review Cultivation: mechanical weeding in dry blocks; turning the soil accelerates vital moisture loss from the root zone.
The latest experience from whip/young tree growers in Belgium is that netting/shading is required over all newly sown seed-raised stock to protect from intense heat and light levels. While protecting vulnerable young plants, netting and frames can only be put on and removed by hand, making it an expensive process.
New introductions – Flower trials and HTA Plant show
Over the last few week there has been a flurry of activity with ongoing new introductions taking place across a range of sites in these annual shows in the Netherlands and England.
Congratulations to Tully Nurseries who launched Hebe Rhubarb Crumble in the UK at the HTA event and won a gold award. It is available in the UK through Bransford Webbs. It features, pink grey and green foliage with white flowers through the summer.
At the Flowertrials this year, Syngenta Flowers introduced a vibrant lineup of innovations designed for performance and impact. The new Begonia semperflorens series Bada Bing Swift (green foliage) and Bada Boom Swift (dark foliage) showed uniformity and can speed up production. The eye-catching Dahlia Coffee Shop ‘Lavender Latte’ dazzled visitors with its rich, dark foliage and elegant semi-double blooms in a refined lavender tone. Cutting raised sunflower Sunfinity® with Double Yellow promises strong reflowers and mildew resistance.
Pan America seed launched a new Bacopa Galactic Mist White. It is seed raised and promises no pinching and cleaning They say “This new genetic resolves the issue of too-early flowering and the cleaning requirements of vegetative genetics, as the plant fully develops prior to flowering”. It has large flowers and is naturally compact. There have been cultivation issue in different selections in Ireland in recent years- Galactic Mist White could be the variety we have been waiting for.
Schneider young plants displayed Verbena bonariensis Flair. Bred by Benary this Verbena grows to just 30 cm tall eliminating growers need for pinching or PGR use.
Florensis presented the overall FleuroStar winner Dahlia coccinea Maxi Noir – Velvet Crush. It has striking, near-black (velvety dark bronze) foliage with massive, fully double pink to purple flowers that measure 10 to 13 cm across. It grows to 35-45 cm tall. It is reported to have a very long flower season- June to October. Combined with mildew resistance- an issue for stressed Dahlia plants this should be a very reliable and successful variety.
Amenity Horticulture Census for 2025 launched
The Department of Agriculture, Food and the Marine (DAFM) has recently launched the 2025 Amenity Horticulture Census to gather essential sector data, inform policy, and fulfil EU reporting obligations. Developed with the CSO and the Horticulture Industry Forum, this year’s streamlined survey features fewer questions. Data on the sector is essential for good planning- the phrase “he holds the data wins the battle” remains true. In addition recent fuel support schemes for specialist growers required applicants to have completed the last horticultural census.
Registered Professional Operators must submit their data using the EUSurvey tool by July 31st. It is noted that responses will be processed securely alongside existing register data; personally identifiable information will never be shared, and only anonymised, aggregated data will be published.
Complete the Amenity Horticulture Census
Results of regulator survey – Ornamental Horticulture facing similar challenges to food producers
The 2026 Agri-Food Regulator Supplier Survey highlights systemic pressures beneath outwardly stable buyer relationships. Key findings include severe margin squeezes from rising input costs (labour, energy, overheads) that suppliers cannot pass on, limited negotiating leverage, and a reluctance to report formal Unfair Trading Practices (UTPs) due to fear of commercial retaliation.
Flowers and plants represent a distinct segment of respondents (4% of direct suppliers). Because ornamental nurseries face identical pressures—long crop cycles with high upfront costs, minimum wage inflation, and a market dominated by major retail/wholesale buyers—this report validates the sector’s vulnerability. It underscores the critical need for growers to protect margins, utilise the Regulator to counter unfair contract terms, and seek transparent pricing from large retailers to sustain long-term business viability.
Fireblight officially removed from Irelands Protected Zone list.
DAFM have notified growers of the revocation of the PZ for fireblight in their latest grower traders notice for 2026- see here. It is expected that this will be reflected across key documents for DAFM in the coming weeks, hopefully reducing the administration burden on growers. There are only a few countries in Europe now that remain free of the bacteria: Estonia, Latvia and Finland, while there are several regions that are free of fireblight e.g. Corsica.
It is noted that the bacterial disease is a latent infection in hawthorn hedge rows it can cause devastating damage to species such as Cotoneaster, Pyracantha and Malus. Copper based treatments after pruning and good hygiene may help reduce spread. Resistant varieties should grown be where the infection risk is considered to be high.
Persistent Weed Management in Field Flower and Tree Production
Controlling stubborn weeds in field-grown trees and flowers requires a targeted, integrated strategy. Mechanical control is growing in importance however established perennials, and some annuals are not well controlled in this way. I note below four problematic species currently challenging field operations. Best control can be achieved right now during active growth. In all cases growers should take great care with soil and machinery movement to prevent the spread of the weed by hitchhiking of roots or seed. Where possible leave working these infested areas until last in the day/programme so as to minimise the movement around the fields. Use of any hormonal herbicides e.g. MCPA, 2,4D, Triclopyr should be used with he greatest of caution due to the risk of damage of ornamental plants with drift or residues in sprayers.
Images below from top right: Equisetum arvense, Petasites fragrans, Nicandra physaloides, Rorippa sylvestris.
Species-Specific Strategies
- Mare’s Tail (Equisetum arvense): Its deep, extensive rhizome network makes mechanical cultivation counterproductive, as slicing fractures the roots and propagates new clones. The waxy cuticle restricts herbicide penetration. Use a heavy roller or bruise the stems prior to applying a systemic herbicide like fluroxypyr (e.g. Arbiter/Binder) or a high-load glyphosate formulation with an added surfactant.
- Winter Heliotrope (Petasites fragrans): This aggressive perennial competes with flowers/tree rows with its massive, light-blocking canopy. Target plants during active growth in mid-to-late summer using localised glyphosate or triclopyr spot treatments. Avoid early tilling, which fragments the highly invasive rhizomes.
- Creeping Yellow Cress (Rorippa sylvestris): This perennial weed is easily spread by its fragile, creeping roots. Along with its close relative Rorippa palutris they favour damper ground. Repeated mechanical hoeing of infestations will reduce the weeds growth but increase spread. Now is an ideal time to use directed post-emergence applications of Triclopyr-based products paired with Dicamba or 2,4-D are highly effective. German research in field production of HNS found residual herbicides foramsulfuron (Conviso One) and Iodosulfuron to have good control. Iodosulfuron is available mixed with Difluenican as Valdor flex and is approved for outdoor ornamentals.
- Shoofly Plant (Nicandra physaloides): While technically a vigorous annual, its prolific seed bank acts like a perennial threat in nursery rows. It has become a weed of tillage crops and gets into tree production etc through crop rotation. Pre emergence residual herbicides—such as Dimethenamid P and Pendimethalin (Wing P) are effective if applied in time – early spring. If there are gaps in the herbicide programme and the weed germinates it is critical to hand-rogue or spot-treat survivors before they set seed.
Management Note: A weed wiper or licker prevents drift to trees and while slow it is the safest method of spot treatment. Always use shielded sprayers to prevent herbicide drift onto tree bark or low-hanging foliage, and rotate chemical modes of action to prevent resistance.
Electronic PPP Record Keeping (Post-2027) reminder
New regulations will change how growers manage spray records. Starting in 2027, the Department of Agriculture, Food and the Marine (DAFM) will transition toward a fully digital, “machine-readable” reporting system.
Key Requirements
- Format: Records must be kept in a digital format that is “machine-readable” (e.g., extractable into .csv or .html files).
- Accessibility: While records do not need to be submitted automatically, they must be made available immediately upon request by DAFM officials.
- Using platforms like Google Forms or Microsoft Forms is an effective way to transition from paper logs to a DAFM-compliant digital format. These tools allow you to create a customised “Spray Log” that can be filled out on a smartphone or tablet immediately after application. A QR code linking to these can be kept in the chemical store/tractor cab for easy access.
New products reminder – Sivanto Prime and Romeo
Romeo bio fungicide prevents powdery and down mildew and botrytis with up to 8 application per ornamental crop. It has on label approval for a number of protected crops: baby leaf, cucumber, courgette, lettuce, strawberries and tomatoes and outdoor endive and grapes. There is EAMU off label approval for outdoor and protected ornamentals. Romeo is marketed by Fargro UK.
See Romeo label here and Romeo instructions for use here
Sivanto Prime insecticide
The aphicide, Sivanto Prime from Bayer has now been officially registered in Ireland for use on a range of edible crops. It has off label authorisation for ornamentals and forest nurseries. Sivanto Prime provides horticultural growers with a new aphicide that aligns with Integrated Pest Management (IPM). Between 1 and 4 applications are permitted per year depending on crop type. The product contains the active ingredient flupyradifurone, IRAC Group 4D. This chemical has already been available for amateur use as Provanto Smart Bug Killer and is permitted on ornamental crops.
See details here- Sivanto Prime label and Sivanto Prime EAMU for non food crops. Note there are some restrictions stipulated which are not normally prescribed and which growers may not be overly familiar with. For example, the product cannot be used on land parcels which slopes towards an intersecting watercourse, that the product can only be applied with drift reducing nozzles and to protect bees for some crops it cannot be partnered FRAC 3 fungicides,
Please Note- extensions of authorisation for minor uses, there is limited evidence of crop safety and/or product efficacy available, and the commercial risk of using this product on the crops/situations listed is borne entirely by the grower.
The Department of Agriculture Off-label Extension of Authorisation for Minor Uses (EAMU) – Non-Food Crops (pdf)
Box moth caterpillar- increased damage and spread due to hot weather.
Recent sustained high temperatures have significantly accelerated the life cycle of the Box tree moth caterpillar. Warmer conditions reduce the incubation period of eggs and speed up larval development, compressed from the typical 30 days down to under 18 days. This allows for an additional generation per season (up to 2-3 lifecycles), leading to rapid population growth, faster geographic spread, and severe defoliation of Buxus sempervirens.
Multi-tier control strategy should be considered to mitigate commercial damage:
- Biological Controls: Bacillus thuringiensis species are approved for forestry and many edible crops but not ornamentals. They are effective at killing caterpillars if ingested by them.
- Pheromone Trapping: mass-trapping pheromone systems to disrupt mating cycles and monitor male adult flight peaks to time spraying precisely.
- Chemical Cover: Chlorantraniliprole products are effective, e.g. Lakota, Laguna, Coragen and Shenzi 200.
Image above of caterpillars feeding on Buxus courtesy of EPPO Matteo Maspero and Andrea Tantardini, Centro MiRT – Fondazione Minoprio (IT).
Dates for your diary
- July 16th Glas horticulture trade show
- August 11th-15th, August Florum tree nursery symposium Germany
