Targeted Invasive Plant Solutions
Beautiful in Your Garden,
But Be Aware
Often mistaken for wildflowers, invasive plants
are spreading through our natural ecosystems,
urban landscapes, and agricultural lands at an
alarming rate. Invasive plants are often quite
striking and attractive, but their beauty can be
deceptive. Invasive plants spread through several
horticultural pathways of invasion including land-
and waterscaping, gardening, and wildflower
seed mixtures. Gardeners, landscapers, retailers,
BC Landscape & Nursery Association, Landscape Awards of Excellence 2008
nurseries, and others have the ability to prevent the
establishment of invasive plants by making informed
choices when selecting, trading or purchasing
horticulture plants and seeds.
Do You Know What
The objectives of this publication are to:
1. Prevent the establishment of new invasive plants Horticulture and Invasive Plants
in British Columbia. BC’s wide range of climates creates some
2. Provide practical solutions for the management of the best growing conditions in Canada,
and disposal of existing infestations. allowing gardeners to grow a diversity of
3. Increase awareness of the negative ecological, attractive and exotic trees, shrubs, and flowers.
social, and economic impacts of invasive plants. This combined with a growing horticulture
4. Encourage responsible or “Garden Smart” industry has resulted in an increased number of
practices. introductions of exotic ornamentals.
The term invasive plant, as used hereafter, includes Sometimes these striking ornamentals escape
provincially listed invasive plants and noxious weeds, as cultivation and spread quickly, forming dense
well as other alien plant species that have the potential patches, thereby displacing native species
to pose undesirable impacts on people, the economy, and disrupting natural ecological processes.
or the environment.
Invasive plant parts and seeds can be
introduced and spread:
Impacts of Invasive Plants 1. Intentionally as an ornamental or food plant;
2. Unintentionally as a by-product of disposal,
Through competition for water, nutrients, and space, primarily by garden waste dumping; and
invasive plants displace desirable vegetation and can 3. Naturally by birds, wildlife, livestock,
disrupt natural ecosystem functions. Lacking natural vehicles, railway cars, and wind.
pathogens or predators, invasive plants can negatively
affect soil productivity, water quality, aquatic habitats, Mechanisms to enforce legislation that
stream bank stability, biodiversity, range resources, addresses horticulture and invasive plants
wildlife habitat, species at risk, wildfire frequency and in BC needs improvement. In response,
intensity, culturally important plants, human health, there is a growing network of partnerships
public infrastructure, recreation, and landscape and collaborations between the horticulture
aesthetics. Invasive plants cause estimated crop losses industry, provincial and local government,
of over $50 million annually in BC (Ministry of Agriculture retailers, regional invasive plant committees,
and Lands), and are the second greatest threat to gardeners, and other concerned individuals to
biodiversity after habitat loss (International Union for address unwanted horticultural plants and stop
the Conservation of Nature). their spread. Such partnerships have lead to the
www.invasiveplantcouncilbc.ca March 2009
Purple Loosestrife PLANT Garden Astilbe PLANT Anise Hyssop PLANT Cardinal Flower
(Lythrum salicaria) INSTEAD: (Astilbe x arendsii) INSTEAD: (Agastache foeniculum) INSTEAD: (Lobelia cardinalis)
L. Scott C. Matheson C. Matheson C. Lewis
development of these “Garden Smart” Targeted Invasive Plant Solutions or T.I.P.S., and a
“Grow Me Instead” booklet, which illustrates the top “unwanted” invasive plants in horticulture
along with suggested non-invasive native or ornamental plant alternatives
Make Informed Choices — be “Garden Smart”
Everyone loves beautiful plants, and making informed choices for your garden or landscape project
can help safeguard BC’s environment and economy for future generations from the impacts of
invasive plants. Before you plant a new species in your garden, ask yourself:
1. “Will the plant be invasive outside my garden?” Many plant traits that are desirable to gardeners—such
as easy germination and establishment, tolerance to drought and frost, rapid growth and abundant seed
production—enable a plant species to become invasive.
2. “If I order a plant from outside BC, could it be invasive in my environment?” It is possible, although there
may be a lag phase before a plant becomes invasive.
3. “What do I need to know from my local nursery or garden centre?” Find out if a plant is a “fast spreader” or
a “vigorous self-seeder” in your planting zone. If so, these are warning signs that the species may be invasive.
4. “Is there an alternate plant I can use instead of one with the potential to become invasive?” Check the
availability of alternative, non-invasive plants suitable for your area.
Choosing Wildflower Seed Mixtures
Many wildflower seed mixes, including those marketed as ‘backyard biodiversity’ and ‘meadow
mix,’ contain invasive plant seeds. A study in 2002 by the University of Washington discovered
that out of 19 packets of wildflowers mixtures, each contained three to 13 invasive plants. A third
of the packets did not list any contents, and only five correctly itemized contents. Refer to the
Invasive Plant Council of BC’s Seed Mixture T.I.P.S. to learn more about selecting appropriate,
non-invasive seed mixtures (www.invasiveplantcouncilbc.ca/resources).
Prevention is the most important and cost-effective invasive plant management strategy, but often the
least used. It is critical to prevent invasive plants from spreading and becoming established in new areas.
Horticulture is a key pathway of invasion of new invasive plants into BC and Canada; therefore, T.I.P.S.
provided for being Garden Smart are focused on PREVENTION. Overall, knowing what you are growing and
selecting the right plant for the right place are the most effective actions you can take.
Integrated Pest Management (IPM)
Since the goal of this document is to prevent the establishment of invasive plants through horticulture, other
invasive plant management options are not described. In the event that invasive plants are introduced,
Integrated Pest Management (IPM) principles should be implemented. IPM is a decision-making process
that includes identification and inventory of invasive plant populations, assessment of the risks that they
pose, and development of well-informed control options that may include a number of methods, site
treatment, and monitoring.
Control methods vary with species, severity of the plant invasion, and site characteristics. Management
strategies will vary by invasive plant species, severity of the plant invasion, and site characteristics. Site-
specific mechanical, chemical, or biological control methods may be applied. For more information on
control methods, consult your regional invasive plant committee, refer to species- and activity-specific
T.I.P.S., or go online to www.weedsbc.ca. To find a regional invasive plant committee near you, visit
www.invasiveplantcouncilbc.ca/regional-committees or call: 1-888-WEEDSBC.
Targeted Invasive Plant Solutions 3
Butterfly Bush PLANT Oceanspray PLANT California Lilac PLANT Red-Flowering Currant
(Buddleja davidii) INSTEAD: (Holodiscus discolor) INSTEAD: (Ceanothus thyrsiflorus) INSTEAD: (Ribes sanguineum)
I & G. Carter L. Scott A. Jarrett C. Matheson
T.I.P.S. for being Garden Smart
ACTIVITY TARGETED INVASIVE PLANT SOLUTIONS
These T.I.P.S. are always applicable:
• Learn about invasive plants in your area and select the right plant for the right place. Be
suspicious of exotic plants promoted as “fast spreaders” or “vigorous self-seeders,” as these are
often invasive plants.
• Before purchasing an exotic plant, check reliable sources: www.invasiveplantcouncilbc.ca or
www.greatplantpicks.org or contact your local nursery or regional invasive plant committee.
• Check with your regional invasive plant committee coordinator to see if the plant is invasive in
your area or call 1-888-WEEDSBC.
• Request only non-invasive plants from your local nursery and gardening centre.
• Control established invasive plants using site and species appropriate methods. For example,
hand pulling, digging, cutting, and mowing.
• Deadhead (remove) flowers, seedpods, and berries of known invasive plants to prevent
reproduction through seeds and to reduce seed spread by birds, wildlife, pets, and people.
• Trade only non-invasive plants and seeds with other gardeners.
• Avoid picking plants from roadsides, gravel pits or other disturbed areas. Many of the prettiest
wildflowers growing along roadsides are aggressive invasive plants that should not be moved to
• Help educate other gardeners in your area through personal contact. This could include
information sharing at gardening club activities, informing neighbours of invasive plants on their
property, online blogs or a simple call to a friend.
• Replace invasive plants with non-invasive exotic or native alternatives.
• Select non-invasive exotic and/or regional native plants for your garden. Native plants are
naturally adapted to the local environment.
• Request that local botanical gardens, nurseries, and gardening clubs promote, display or sell
• Contact your local chapter of the North American Native Plant Society (www.nanps.org) or
Seeds of Diversity (www.seeds.ca) for more information on native plant nurseries and seed
• Consult the Invasive Plant Council of BC’s Grow Me Instead booklet to learn more about
non-invasive alternatives to horticulture’s most unwanted plants.
• Dispose of invasive plant parts and seeds responsibly (i.e., bag and landfill or incinerate).
• Don’t “recycle” garden debris into a public park or natural area.
• Avoid composting many invasive plants, as they can quickly re-establish themselves.
• Contact your regional invasive plant committee to learn more about responsible disposal
techniques in your area.
• Use wildflower seed mixes with caution, as they may contain invasive plant seeds. Read
the label to see what species are listed and check if they are desirable for your location by
contacting your regional invasive plant committee.
• Read the label to see what species are listed and check if they are desirable for your location.
Check with your regional invasive plant committee to find out which species listed in the mixture
are invasive for your area.
• Be aware that in some cases not all of the plants contained within the mixture will be listed.
• Monitor seeded areas for invasive plants, and control seedlings immediately.
• Don’t collect ‘wildflower’ seeds from roadsides, gravel pits, or other disturbed areas.
Legislation and Regulations Provincial and Regional Coordination
Invasive Plant Strategy for British Columbia:
The Seeds Act defines seed as ‘any plant part of any species invasive-plant-strategy.pdf
belonging to the plant kingdom, represented, sold, or used to
grow a plant’. Therefore, grain fed to animals (e.g. birdseed) Species Identification and Management
cannot be regulated under the Seeds Act and Regulations. BC Ministry of Agriculture and Lands. 2002. Field
The Seeds Act and Regulations are relevant to large-scale Guide to Noxious and Other Selected Weeds of
plantings, roadsides, landscaping, gardening, ornamentals, British Columbia, 4th ed. www.agf.gov.bc.ca/
land reclamation, soil conservation, green cover, wildlife cropprot/weedguid/weedguid.htm
grazing or habitat, wetland restoration, and other similar
activities. http://laws.justice.gc.ca/en/S-8 BC Ministry of Forests and Range Invasive Alien
The Plant Protection Act and Regulations aim to ‘prevent
the importation, exportation, and spread of pests injurious E-Flora BC, Electronic Atlas: www.eflora.bc.ca
to plants and to provide for their control and eradication
and for the certification of plants and other things.’ Global Invasive Species Database:
Provincial Invasive Plant Council of BC. Targeted Invasive Plant
In BC, invasive plant management on all lands (Crown and Solutions series: www.invasiveplantcouncilbc.ca
non-Crown) is regulated by the BC Weed Control Act, and
the management of specific Crown lands is regulated by Weeds BC (BC Ministry of Agriculture and Lands):
the Forest and Range Practices Act (FRPA), the Community www.weedsbc.ca
Charter, and the Integrated Pest Management Act (IPMA).
See the Legislative Guidebook for more information. Provincial Inventory and Mapping Database
www.invasiveplantcouncilbc.ca/resources/reports Invasive Alien Plant Program (IAPP):
The FRPA requires forest and range managers to specify
and implement measures that prevent the introduction or Integrated Pest Management
spread of the 42 invasive plants listed under the Invasive BC Ministry of Environment Integrated Pest
Plants Regulation within their forest stewardship plans, Management Program: www.env.gov.bc.ca/epd/
woodlot licence plans, range use plans, and range epdpa/ipmp/index.html
stewardship plans. www.for.gov.bc.ca/tasb/legsregs/frpa/
The WCA requires all land occupiers to control the Partners
spread of 48 provincial and/or regional noxious weeds Funding for this project was provided in part by the Invasive
on their land and premises, and specifies provisions for Alien Species Partnership Program (IASPP), a Government of
transportation, movement, and cleaning of machinery. Canada initiative.
Thank you to the Horticulture Advisory Committee, who
The IPMA regulates herbicide applications that may be advised the development of these Garden Smart T.I.P.S.:
used to control invasive plant infestations. Becky Brown, Ministry of Agriculture and Lands; Hedy Dyck,
www.qp.gov.bc.ca/statreg/stat/I/03058_01.htm British Columbia Landscape and Nursery Association;
Douglas Justice, University of British Columbia Botanical
The Community Charter is enabling legislation that Garden; Penny Koch, Master Gardeners Association of
provides powers that municipalities may use for, among BC; Colleen MacDonald, Sage Green Projects Inc; Tasha
other things, invasive plant control. Authority for invasive Murray, Greater Vancouver Invasive Plant Council;
plant control is available under either weed control Rod Nataros, NATS Nursery; Scott Pearce, Gardenworks;
powers or broad powers for the protection of the natural Paulus Vrijmoed, Linnaea Nurseries; and Pam Wesley,
environment. www.qp.gov.bc.ca/statreg/stat/c/03026_00.htm Coastal Invasive Plant Committee.
PLACE YOUR STAMP HERE
References and Links
Invasive Plants in Horticulture
Garry Oak Ecosystems Recovery Team. (2007). Garry Oak
Gardener’s Handbook. Retrieved 03 19, 2009, from Garry
Oak Ecosystems Recovery Team: www.goert.ca
Invasive Plant Council of BC. (2007). Report 4: Minimizing
the Impacts of Invasive Plants in Horticulture. Retrieved 03
19, 2009, from Invasive Plant Council of BC: REPORT A WEED:
CONTACT US: 1-888-WEEDSBC
The Nature Conservancy, et al. (2008). GardenSmart www.invasiveplantcouncilbc.ca
Oregon: a guide to non-invasive plants. Retrieved 03 19, Go to “Contact Us” link or call,
2009, from The Nature Conservancy: www.nature.org write or fax us at:
Washington Invasive Species Coalition. (2006). Garden #104 - 197 North 2nd Avenue
Wise: Non-Invasive Plants for Your Garden. Retrieved 03 19, Williams Lake, BC V2G 1Z5
2009, from Washington Invasive Species Coalition: Phone: (250) 392-1400
www.invasivespeciescoalition.org Fax: (250) 305-1004