PRE Pairing for Success: Emerging Invasives, Contentious Cultivars & Common Ground



PRE logo

Through a 2017 Farm Bill grant, 4 botanic gardens across the nation commenced deployment of the PRE™ (Plant Risk Evaluator) tool and database. Each botanic garden partner assessed 50 plants of interest or contention within their region, for a total of 200 regional assessments. Please see below for links to PDFs of each evaluation.

PRE is a 20 question plant risk assessment tool. It is also an online platform and database enabling those involved in non-native, terrestrial plant production to know before they grow if a plant poses a potential regional invasive risk. Click here for more information on PRE. If you’re interested in getting involved as a PRE reviewer or having a PRE account for your organization, please email us at



This year-long project significantly advanced the PRE tool, database, and process in many ways: improving ease of use for users; growing the database beyond California; increasing awareness of PRE as a resource nationally; and providing better understanding of each phase and role within the PRE process. Questions we aimed to answer over the course of the project included:

Collaboration: How does PRE (tool + process) advance substantive collaboration among horticultural stakeholders which results in better plants being promoted and fewer invasive plant risks?

Multi-Region Comparison: For taxa evaluated in 2 or more states, how do state assessment ratings compare?

Invasive Risk Categories: For taxa rated as “Evaluate Further”, did missing biological information contribute to the assessment outcome; and if so, then what kind of information would be needed to answer more questions? Would this resolve the outcome to either Low Risk or High Risk?  For PRE purposes, would “Moderate Risk” be a more appropriate term than “Evaluate Further”?

Cultivars: How does the PRE model work for cultivars? Can PRE be improved to handle unique aspects of cultivars, or any non-native plants new to the marketplace (and science), with very little information about their behavior on the landscape?

Invasive Concern: Which of the taxa evaluated are predicted to have a high risk of invasiveness in the state? Low risk of invasiveness? Following stakeholder review, which taxa could be considered invasive risk priorities in the state, if not considered “emerging invasives?”

To increase stakeholder collaboration and improve the quality of the evaluations, we aimed to have each evaluation reviewed by representatives from industry, plant science, and conservation. Most evaluations were reviewed twice; all evaluations were reviewed at least once. Please note: for a given evaluation, the PDF report might not reflect all reviews, as stakeholders began reviewing evaluations before this functionality (marking the evaluation reviewed) was added to the PRE site.

Regional Collaborators:
Atlanta Botanical Garden
Botanical Research Institute of Texas with Fort Worth Botanic Garden
Chicago Botanic Garden
University of Minnesota Landscape Arboretum

Each region evaluated 50 plants including landscape plants of significant economic impact grown or sold in the region and contentious cultivars in the region. 23 plants of common concern were also assessed (evaluated in 2 or more regions).

Regional Evaluation PDF Links

Plant Region Download Report
Acer buergerianum Georgia  Download PDF
Agapanthus praecox ssp. minimus ‘Peter Pan’ Georgia  Download PDF
Ailanthus altissima Georgia  Download PDF
Albizia julibrissin Georgia  Download PDF
Ampelopsis brevipedunculata Georgia  Download PDF
Ardisia crenata Georgia  Download PDF
Arundo donax Georgia  Download PDF
Berberis thunbergii Georgia  Download PDF
Berberis thunbergii ‘Crimson Pygmy’ Georgia  Download PDF
Broussonetia papyrifera Georgia  Download PDF
Buddleja davidii ‘Black Knight’ Georgia  Download PDF
Camellia oleifera Georgia  Download PDF
Celastrus orbiculatus Georgia  Download PDF
Cinnamomum camphora Georgia  Download PDF
Dioscorea bulbifera Georgia  Download PDF
Elaeagnus pungens Georgia  Download PDF
Elaeagnus umbellata Georgia  Download PDF
Euonymus alatus ‘Compactus’ Georgia  Download PDF
Euonymus fortunei Georgia  Download PDF
Euonymus fortunei ‘Coloratus’ Georgia  Download PDF
Festuca arundinacea Georgia  Download PDF
Firmiana simplex Georgia  Download PDF
Hibiscus syriacus ‘Diana’ Georgia  Download PDF
Ilex cornuta ‘Needlepoint’ Georgia  Download PDF
Lagerstroemia indica ‘Natchez’ Georgia  Download PDF
Ligustrum japonicum ‘Recurvifolium’ Georgia  Download PDF
Ligustrum sinense ‘Sunshine’ Georgia  Download PDF
Liriope muscari ‘Variegata’ Georgia  Download PDF
Lonicera fragrantissima Georgia  Download PDF
Lonicera japonica Georgia  Download PDF
Lygodium japonicum Georgia  Download PDF
Mahonia bealei Georgia  Download PDF
Melia azedarach Georgia  Download PDF
Miscanthus sinensis ‘Scout’ Georgia  Download PDF
Nandina domestica ‘Firepower’ Georgia  Download PDF
Paulownia tomentosa Georgia  Download PDF
Pistacia chinensis Georgia  Download PDF
Poncirus trifoliata Georgia  Download PDF
Pyracantha coccinea Georgia  Download PDF
Pyrus calleryana ‘Bradford’ Georgia  Download PDF
Quercus acutissima Georgia  Download PDF
Reynoutria japonica Georgia  Download PDF
Rosa multiflora Georgia  Download PDF
Schinus terebinthifolia Georgia  Download PDF
Spiraea japonica ‘Gold Mound’ Georgia  Download PDF
Triadica sebifera Georgia  Download PDF
Vernicia fordii Georgia  Download PDF
Vinca major Georgia  Download PDF
Vinca minor Georgia  Download PDF
Wisteria sinensis Georgia  Download PDF
Acer palmatum Illinois  Download PDF
Acer platanoides ‘Crimson King’ Illinois  Download PDF
Acer platanoides ‘Royal Red’ Illinois  Download PDF
Acer tataricum ssp. ginnala Illinois  Download PDF
Aegopodium podagraria Illinois  Download PDF
Aegopodium podagraria ‘Variegatum’ Illinois  Download PDF
Alnus glutinosa Illinois  Download PDF
Ampelopsis brevipedunculata ‘Elegans’ Illinois  Download PDF
Berberis thunbergii ‘Crimson Pygmy’ Illinois  Download PDF
Berberis thunbergii ‘Rose Glow’ Illinois  Download PDF
Buddleja davidii ‘Black Knight’ Illinois  Download PDF
Buddleja davidii ‘Royal Red’ Illinois  Download PDF
Euonymus alatus ‘Compactus’ Illinois  Download PDF
Euonymus alatus ‘Rudy Haag’ Illinois  Download PDF
Euonymus fortunei Illinois  Download PDF
Forsythia ‘Sunrise’ Illinois  Download PDF
Frangula alnus ‘Ron Williams’ FINE LINE Illinois  Download PDF
Gentiana cruciata Illinois  Download PDF
Geranium sanguineum var. striatum Illinois  Download PDF
Hedera helix ‘Thorndale’ Illinois  Download PDF
Hemerocallis ‘Stella d’Oro’ Illinois  Download PDF
Hosta ‘Halcyon’ Illinois  Download PDF
Hosta sieboldiana ‘Frances Williams’ Illinois  Download PDF
Hydrangea macrophylla ‘Bailmer’ ENDLESS SUMMER THE ORIGINAL Illinois  Download PDF
Hypericum x inodorum ‘Kolmapuki’ PUMPKIN Illinois  Download PDF
Lilium szovitsianum Illinois  Download PDF
Lysimachia nummularia ‘Aurea’ Illinois  Download PDF
Lythrum virgatum ‘Morden Gleam’ Illinois  Download PDF
Malus ‘Adams’ Illinois  Download PDF
Malus ‘Donald Wyman’ Illinois  Download PDF
Malus ‘Jewelcole’ RED JEWEL Illinois  Download PDF
Miscanthus sinensis ‘Gracillimus’ Illinois  Download PDF
Miscanthus sinensis ‘Morning Light’ Illinois  Download PDF
Miscanthus sinensis var. condensatus ‘Cabaret’ Illinois  Download PDF
Nepeta racemosa ‘Walker’s Low’ Illinois  Download PDF
Pennisetum alopecuroides Illinois  Download PDF
Polygonatum glaberrimum Illinois  Download PDF
Pyrus calleryana ‘Bradford’ Illinois  Download PDF
Pyrus calleryana ‘Glen’s Form’ CHANTICLEER Illinois  Download PDF
Reynoutria japonica ‘Devon Cream’ Illinois  Download PDF
Reynoutria japonica ‘Variegata’ Illinois  Download PDF
Rosa oxyodon Illinois  Download PDF
Salvia x sylvestris ‘Mainacht’ MAY NIGHT Illinois  Download PDF
Sambucus tigranii Illinois  Download PDF
Spiraea japonica Illinois  Download PDF
Syringa reticulata Illinois  Download PDF
Tilia cordata ‘PNI 6025’ GREENSPIRE Illinois  Download PDF
Viburnum dilatatum ‘Henneke’ CARDINAL CANDY Illinois  Download PDF
Vinca minor Illinois  Download PDF
Weigela florida ‘Red Prince’ Illinois  Download PDF
Acer platanoides Minnesota  Download PDF
Acer platanoides x truncatum ‘Keithsform’ Minnesota  Download PDF
Acer platanoides x truncatum ‘Warrenred’ Minnesota  Download PDF
Acer pseudosieboldianum Minnesota  Download PDF
Acer pseudosieboldianum x palmatum ‘IslAJ’ Arctic Jade Minnesota  Download PDF
Acer pseudosieboldianum x palmatum ‘IslNW’ North Wind Minnesota  Download PDF
Acer tataricum ssp. ginnala Minnesota  Download PDF
Aegopodium podagraria ‘Variegatum’ Minnesota  Download PDF
Ajuga reptans Minnesota  Download PDF
Ampelopsis brevipedunculata Minnesota  Download PDF
Berberis thunbergii ‘Bagatelle’ Minnesota  Download PDF
Berberis thunbergii ‘Crimson Pygmy’ Minnesota  Download PDF
Buddleja davidii Minnesota  Download PDF
Caragana arborescens Minnesota  Download PDF
Celastrus orbiculatus Minnesota  Download PDF
Cercis canadensis Minnesota  Download PDF
Digitalis lanata Minnesota  Download PDF
Dipsacus fullonum Minnesota  Download PDF
Dipsacus laciniatus Minnesota  Download PDF
Elaeagnus angustifolia Minnesota  Download PDF
Euonymus alatus ‘Compactus’ Minnesota  Download PDF
Lamium maculatum Minnesota  Download PDF
Lamium maculatum ‘Beacon Silver’ Minnesota  Download PDF
Leucanthemum vulgare Minnesota  Download PDF
Leymus arenarius ‘Blue Dune’ Minnesota  Download PDF
Lonicera caerulea ‘Cinderella’ Minnesota  Download PDF
Lonicera caerulea ‘Tundra’ Minnesota  Download PDF
Lonicera tataricum ‘Honeyrose’ Minnesota  Download PDF
Miscanthus sinensis ‘Graziella’ Minnesota  Download PDF
Miscanthus sinensis ‘Purpurascens’ Minnesota  Download PDF
Miscanthus sinensis ‘Strictus’ Minnesota  Download PDF
Miscanthus sinensis ‘Zebrinus’ Minnesota  Download PDF
Morus alba Minnesota  Download PDF
Phellodendron amurense Minnesota  Download PDF
Pinus sylvestris Minnesota  Download PDF
Populus alba Minnesota  Download PDF
Pyrus calleryana ‘Bradford’ Minnesota  Download PDF
Pyrus ussuriensis Minnesota  Download PDF
Rhododendron ‘Electric Lights Double Pink’ Minnesota  Download PDF
Robinia pseudoacacia Minnesota  Download PDF
Rosa multiflora Minnesota  Download PDF
Scilla siberica Minnesota  Download PDF
Sorbus alnifolia Minnesota  Download PDF
Syringa reticulata Minnesota  Download PDF
Tanacetum vulgare Minnesota  Download PDF
Taxus cuspidata Minnesota  Download PDF
Ulmus pumila Minnesota  Download PDF
Viburnum lantana ‘Mohican’ Minnesota  Download PDF
Viburnum opulus L. Minnesota  Download PDF
Weigela florida ‘Red Prince’ Minnesota  Download PDF
Abelia xgrandiflora Texas  Download PDF
Albizia julibrissin Texas  Download PDF
Allium sativum Texas  Download PDF
Arundo donax Texas  Download PDF
Asclepias curassavica Texas  Download PDF
Bothriochloa ischaemum Texas  Download PDF
Buddleja davidii Texas  Download PDF
Clematis terniflora Texas  Download PDF
Clerodendrum bungei Texas  Download PDF
Colocasia esculenta Texas  Download PDF
Elaeagnus umbellata Texas  Download PDF
Eragrostis curvula Texas  Download PDF
Euonymus alatus Texas  Download PDF
Euonymus fortunei Texas  Download PDF
Firmiana simplex Texas  Download PDF
Hedera helix Texas  Download PDF
Houttuynia cordata Texas  Download PDF
Ilex aquifolium Texas  Download PDF
Ilex cornuta ‘Burfordii’ Texas  Download PDF
Ipomoea batatas Texas  Download PDF
Lagerstroemia indica Texas  Download PDF
Lantana camara Texas  Download PDF
Ligustrum sinense ‘Sunshine’ Texas  Download PDF
Liriope spicata Texas  Download PDF
Lonicera fragrantissima Texas  Download PDF
Lonicera japonica Texas  Download PDF
Lonicera maackii Texas  Download PDF
Loropetalum chinense Texas  Download PDF
Loropetalum chinense var. rubrum ‘Sato’s Dwarf Red’ Texas  Download PDF
Miscanthus sinensis Texas  Download PDF
Nandina domestica Texas  Download PDF
Pennisetum alopecuroides Texas  Download PDF
Photinia x fraseri Texas  Download PDF
Phyllostachys aurea Texas  Download PDF
Pistacia chinensis Texas  Download PDF
Plumbago auriculata Texas  Download PDF
Portulaca grandiflora Texas  Download PDF
Pyrus calleryana ‘Bradford’ Texas  Download PDF
Rhaphiolepis indica var. umbellata Texas  Download PDF
Ricinus communis Texas  Download PDF
Ruellia brittoniana ‘Chi Chi’ Texas  Download PDF
Triadica sebifera Texas  Download PDF
Ulmus pumila Texas  Download PDF
Vinca major Texas  Download PDF
Viola odorata Texas  Download PDF
Vitex agnus-castus Texas  Download PDF
Wisteria sinensis Texas  Download PDF
Wisteria sinensis ‘Angie’ Texas  Download PDF
Wisteria sinensis ‘Jako’ Texas  Download PDF
Wisteria sinensis ‘Prolific’ Texas  Download PDF


How to Answer PRE Questions Guide – a guide for screeners on how to answer the 20 PRE questions, to maximize consistency and ensure screeners understand what the question is asking

PLOS ONE Published Research: The Development of a Plant Risk Evaluation (PRE) Tool for Assessing the Invasive Potential of Ornamental Plants – the Conser et al. research model upon which the online PRE is built.

Project Puts Collaboration First in Answering, “What’s Invasive?” — PlantRight blog post with more information about the 2017 Farm Bill project in the form of an editorial piece. Also covers the tool’s background and development and includes links to interviews with PRE screeners from all 4 botanic gardens.



This material was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS). It may not necessarily express APHIS’ views.

PRE Screeners:

Kylie Bucalo, Atlanta Botanical Garden

Lila Uzzell, Atlanta Botanical Garden

Melina Lozano Duran, Atlanta Botanical Garden

Emily Russell, Chicago Botanic Garden

Mike Monterusso, University of Minnesota Landscape Arboretum

Dan Miller, University of Minnesota Landscape Arboretum

Steve McNamara, University of Minnesota Landscape Arboretum

Kim Taylor, Botanical Research Institute of Texas

Volunteer Stakeholder Reviewers:

Brian Jernigan (Georgia)

Eamonn Leonard (Georgia)

Chris Butts (Georgia)

Dave Coyle (Georgia)

John Ruter (Georgia)

Allan Armitage (Georgia)

Stewart Chandler (Georgia)

Harvey Cotten (Georgia)

Karan Rawlins (Georgia)

Henning von Schmeling (Georgia)

Shelly Matthew Prescott (Georgia)

Richard Hawke (Illinois)

Kim Shearer (Illinois)

Chris Evans (Illinois)

Shannon McEnerney (Illinois)

Jeff Mengler (Illinois)

Mike Daab (Illinois)

Clair Ryan (Illinois)

Linda MacKechnie (Illinois)

John Taft (Illinois)

Steve Worth (Illinois)

Mike Yanny (Illinois)

Laura Van Riper (Minnesota)

Tim Power (Minnesota)

Emilie Justen (Minnesota)

Angelique Dahlberg (Minnesota)

Christy Marsden (Minnesota)

Tim Vogel (Minnesota)

Mary Meyer (Minnesota)

Tom Buechel (Minnesota)

Matthew Kaproth (Minnesota)

Chel Anderson (Minnesota)

Charlotte Reemts (Texas)

Hans Landel (Texas)

Mengmeng Gu (Texas)

Steve Moore (Texas)

Trey Wyatt (Texas)

Barron Rector (Texas)

Jed Aplaca (Texas)

Autumn Smith-Herron (Texas)

Dave Waetjen, UC Davis Information Center for the Environment (PRE website developer)

Laura Miller, Texas A&M University Extension (Commercial Horticulture, PRE connector)

Sustainable Conservation

Horticultural Research Institute

Travis Bean  (PRE Science Team/Advisory Group)

Elizabeth Brusati (PRE Science Team/Advisory Group)

Ramona Robison  (PRE Science Team/Advisory Group)

Joe DiTomaso (PRE Science Team)

Dean Kelch (PRE Science Team)

PRE Advisory Group