Introducing the Project
Herbicide phytotoxicity testing on a range of container-grown ornamental plant species
This project has been funded by HCP Ltd using returned grower’s AHDB levy monies in the form of a grant payment to support plant protection improvements.
A range of short-term crop protection focused projects will be funded across all of horticulture using the funds, a number of which will cover the various sectors of ornamental horticulture including hardy nursery stock, bedding and pot plants, cut flowers, and bulbs (narcissus).
Various trade and crop associations, and grower groups are involved in the generation of the project proposals.
Project objective
The objective of this eight-month trial is to assess the safety of six new and existing herbicide products with pre- and post-emergence activity, for use over container-grown ornamentals, to add to the limited range of products currently available and used commercially. As part of the project, the herbicide products have already been applied, and will be applied again, to 26 container-grown plant genus/species at two distinct timings, early spring, and late summer 2026, to provide an indication about their relative safety over different stages of crop growth.
Introducing the HCP herbicide phytotoxicity trial
Herbicide products examined and trial plant genus/species
The herbicide products examined in the trial include:
- Broadway Star (florasulam + pyroxsulam), post-emergence herbicide. EAMU 1118/25.
- Emerger (aclonifen), residual herbicide for broad-leaf and grass weed control. EAMUs 3340/25 and 3341/25.
- Goltix Titan (metamitron + quinmerac), residual and post-emergence herbicide. EAMU 1318/25.
- Plus, three other coded herbicide products.
See the HTA EAMU technical factsheets for further detail on each named herbicide product (HTA members only).
The genus/species used in the trial are a mixture of climbers, grasses, herbaceous, and shrubs as summarised in the table below, a total of 84 plants of each were treated.
|
Name |
Pot size |
|
Buddleja davidii ‘Royal Red’ |
3 L |
|
Carex testacea |
3 L |
|
Ceanothus ‘Blue Mound’ |
3 L |
|
Choisya ternata ‘White Dazzler’ |
3 L |
|
Clematis ‘Nubia’ TM Evipo079(N) |
3 L deep |
|
Cornus alba ‘Baton Rouge’ |
3 L |
|
Euonymus fortunei ‘Emerald Gaiety’ |
2 L |
|
Geranium ‘Rozanne’ |
2 L |
|
Hebe franciscana ‘Variegata’ |
3 L |
|
Helenium ‘Short n Sassy’ |
2 L |
|
Hosta ‘Shadowland ™ Empress Wu’ |
2 L |
|
Hydrangea paniculata ‘Framboisine’ |
3 L |
|
Jasminum officinale |
3 L deep |
|
Lavandula ang ‘Hidcote’ |
3 L |
|
Lonicera japonica ‘Halliana’ |
3 L deep |
|
Lonicera nitida ‘Garden Clouds Copper Glow’ |
3 L |
|
Philadelphus ‘Mrs E. L. Robinson’ |
3 L |
|
Photinia x fraseri ‘Scarlet Blaze’ |
3 L |
|
Potentilla fruticosa ‘Abbotswood’ |
3 L |
|
Prunus laurocerasus 'Etna' |
2L |
|
Salvia nemorosa ‘Caradonna’ |
2 L |
|
Sambucus nigra ‘Black Beauty’ |
3 L |
|
Sedum ‘Rose Carpet’ |
2 L |
|
Spiraea japonica ‘Shirobana’ |
3 L |
|
Stipa arundinacea (syn. Anemanthele lessoniana) |
3 L |
|
Veronica ‘Ulster Dwarf Blue’ |
2 L |
Individual genus/species position were randomised within each treatment plot.
Trial layout showing the range of plants tested
Project delivery
The trial has been set out on commercial production beds at Darby Nursery Stock, Old Feltwell Road, Methwold, Thetford. Herbicide applications have been made/will be made using a gas-powered precision sprayer, by staff from the Vegetable Consultants Association to delivery precise amounts of product to each container. Plant scoring systems have been designed to record (a) visible damage on plants and (b) subsequent growth. A representative number of plants will be selected for scoring each treatment, with scoring prior to each application, two weeks post application, one month post application, two months post application and six months post application. A final marketability score will be given at the end of the trial. Events and relevant project output are planned throughout the life of the project.
Project consortium members
