Posted Date: April 12, 2025

Tags: Meetings  

What’s in that seed mix?

Wildflower mixes, Pollinator mixes, or Butterfly mixes can be an attractive way of easily establishing some beautiful flowers and trying to help out pollinators. However, these mixes can often contain invasive species that pose an ongoing risk to native plants and can reduce biodiversity. The horticulture trade is a major vector for the introduction and spread of invasive plants. Making sure you don’t plant invasive plants in your garden can help protect the native plants and biodiversity around you.

One of the best things about living in the Fraser Valley is our proximity to nature, most of us live within walking distance to a park or other natural areas, allowing us to enjoy our beautiful landscape and the biodiversity that we coexist with. Because of that, it’s important to remember that your garden is connected to other gardens and natural areas around you. The plants you grow can spread outside of your yard and into the surrounding natural areas by wind, by birds and animals, or even by your boots/clothing! What you choose to grow may not stay in your yard or the planter box if we are not careful.

Good intentions, but let’s slow down

Many wildflower mixes contain invasive plants as they can seem promising for people looking to grow easy low maintenance flowers for both themselves and pollinators. We love these lovely, well-intentioned people who want to help our biodiversity, and our insects and pollinators. 

However, in 2022, the Invasive Species Council of BC conducted a scan of 16 seed distributors in BC and found that almost all of them sold at least one invasive species. In 2002, University of Washington researchers grew 19 wildflower seed mixes and found that each contained 3 to 13 invasive species. Gardeners with the best of intentions can still easily buy invasive seeds often without even knowing.

Don’t get fooled by a pretty face

Many invasive plants get introduced because they are pretty plants with beautiful flowers! A few species that commonly occur in wildflower seeds mixes and are considered invasive in the Fraser Valley include:

• Bachelor’s button aka Cornflower (Centaurea cyanus)

• Baby’s breath (Gypsophila paniculata)

• Foxglove (Digitalis purpurea)

• Dame’s rocket (Hesperis matronalis)

• Mountain bluet (Centaurea montana)

• Comfrey (Symphytum officinale)

It is very important to make sure that we are not selecting “wildflowers” with traits that can make a plant invasive. Words like “low maintenance”, “establishes easily”, “grows quickly”, “resistant”, “tolerates a wide variety of conditions” can be indicators that those plants may be able to spread beyond your garden. Remember, if you are a “black-thumb” (as opposed to a green-thumb) looking to plant something that you can’t possibly kill, what happens if this plant is taking over and you need to keep it under control?

If they’re invasive, why can I still buy them?

Only some invasive plants are regulated in BC and covered in the BC Noxious Weed Act. Even then, this is only limited to physical stores. On the internet, anyone can buy seeds online and plant them - there are very few ways of regulating or enforcing people from doing so (a few years ago, people across the country even received “mysterious” packages of seeds of unknown origin).  

Unfortunately, currently, there is no legislation that prevents the sale of many invasive plants (this is a whole issue worthy of its own blog post). This means that invasive plants that are not on the list may still be sold in seed mixes, and it’s up to buyers to be cautious. 

Names can be so confusing

Unfortunately, trying to avoid invasive seeds in seed mixes is not as easy as it might seem. If you were buying a seed pack with just one type of seed, it is usually very obvious and clear as to what you are buying. Unfortunately, when you are buying a “mix”, many seed mixes do not include information on what species are included, making it impossible to determine whether they contain invasive species. 

Even when the species included in the mix are listed, some plants have multiple common names! So we end up needing to rely on the Latin name to determine what is actually in the package. Unfortunately, there are no packaging rules, so often, the Latin names are also not included on the package. In addition to containing known invasive species, seed packets can also contain contaminant seed not labelled, and the introduction of new invasive seeds through contaminated seed packets can be another concern.

Fortunately, there are a few ways to help minimize some of these concerns. 

• Some seed packs have their list on their website instead of on the package itself, you can quickly check online what plants are included in the mix. Usually if they have a list online, those should include the Latin name, helping to better determine what is in the mix pack.

• Purchasing single plant packages can help reduce the risk of having unknown plants - you would be getting exactly what you expect from plant names on the package. You can make your own mix by buying multiple single-plant seed packs and combining them.

What even are these mixes for anyway?

By definition, wildflowers are flowers that were not planted on purpose. They grow freely and without human intervention. But “wildflowers” that grow naturally and freely differ depending on where the location is - what might be considered a “wildflower” in Florida, are not likely to be a wildflower in British Columbia, and what might be considered a “wildflower” in even Kamloops, is not likely a natural wildflower in Abbotsford.

Pollinator mixes or Butterfly mixes are seed mixes are meant to support pollinating insects or butterflies, thinking that this would help our biodiversity and local insect populations. But just because a plant helps pollinators, does not mean they help OUR pollinators (ie. European honeybees pollinate plants very differently compared to our native Bumblebees). And just because a plant may help to provide nectar to butterflies does not mean they support ALL the life stages of a butterfly (ie. caterpillars or pupae stages). A plant may support SOME pollinators or the butterfly life stage, but it does not mean they are not necessarily native or non-invasive. 

Some seed producers might grow their own seeds, but some producers might be wild-harvesting their seeds - that is not a good practice if we want to know for sure what plants are included in the seed packs. In fact, some of the locally available seed mixes that you might find in big box stores or dollar stores are from entirely different biogeoclimatic zones like Montana, Ontario, Manitoba, or even California - places with plants and wildlife that are very different from the Fraser Valley. 

So the question becomes, if we are planting these seeds to help our local pollinators, butterflies, and wildlife, but we are using seeds that are not composed of local plants - then are we actually helping our local biodiversity?

Native seeds mean native plants that support native wildlife

Many people buy wildflower mixes to help out local pollinators. However, wildflower seed mixes rarely contain plants native to the Fraser Valley. Native plants and native pollinators have co-evolved over millenia to form strong relationships. Native plants can help support some of our native bees that only pollinate a smaller number of species and rely on those species for their survival. 

When planting for native pollinators consider plants such as 

• Giant blue eye mary (Collinsia grandiflora)

• Sea blush (Plectritis congesta)

• Goldenrod (Solidago lepida/Solidago canadensis)

• Fireweed (Chamerion angustifolium)

• Large-leaved lupine (Lupinus polyphyllus)

• Lance self heal (Prunella vulgaris ssp. lanceolata)

• Woolly sunflower (Eriophyllum lanatum)

• Pearly everlasting (Anaphalis margaritacea)

• Nodding onion (Allium ceruum)

These plants are all native to the Fraser Valley and help support a diversity of our pollinators.

Okay, I get it, but how do I select seeds?

Hopefully by this point, you understand the importance of choosing your seeds carefully, and also knowing what you are growing! So how can you choose seeds that work for you, and avoid invasive plants?

There are many different seed options out there, let’s focus on some questions to consider before making any purchases:

1. Be honest with yourself about your goals for the site - what do you want the space to look like or what do you want the space to do?

   • Do you want to attract birds? Help our bees? Have pretty flowers to look at? Or do you just want to cover a bare patch of dirt? 

   • Will the seeds you hope to plant help you achieve your goal?

 

1. Can you choose native plants and/or non-invasive plants instead? 

   • The PlantWise Grow Me Instead Guide can help you find alternatives

2. Are you buying your seeds from a reputable source? Was the seed grown locally?

   • Locally grown seed is less likely to be contaminated with invasive seeds that aren’t yet established in the area. By sourcing seed locally you can help prevent new introductions of invasive plants. 

3. Do you need to buy a “mix”? Or can you select some single-plant seed packs?

   • It is much easier to avoid invasive plants when choosing single-plant seed packs over mixes, since you can better research what you would be growing.

4. Read the seed pack label - does it list the plant species? Do they include the Latin names?

   • The Latin names allow you to know what you’re actually planting since plants can have many different common names. You may need to go online to the seed company’s website to get those details. 

   • If they don’t list the species, you may need to consider looking for alternative options.

5. Research the plant

   • Does the seed mix contain any plants invasive to the Fraser Valley? Our priority list should help you avoid the priority invasive species.

   • If the species are not on our list - how are these plants being described, what words are being used? If the plant is being described with words similar to “low maintenance”, “resistant”, “tolerates a wide variety of conditions”, maybe consider giving this plant some more thought about what your monitoring and follow up efforts are in case this plant does start to spread quickly.

Let’s keep learning

For more information on seed mixes and invasive plants, check out these reports and guides:

• Alberta Native Plant Council’s 2006 Guidelines for the Purchase and Use of Wildflower Seed Mixes

• Penn State University’s post on Understanding Wildflower Seed Mixes

• Invasive Species Council of BC (ISCBC)’s post What’s in Your Seed Mix?

• Sea to Sky Invasive Species Council (SSISC)’s post on Wildflower Seed Mixes

• Invasive Species Council of BC (ISCBC)’s Seed Mix Factsheet

For more information on which native plants to choose to best support native bees and other pollinators check out these fantastic resources:

• Fraser Valley Conservancy’s guide to Gardening with Native Plants

• BC Native Bees resource on Plants for Coastal BC Bees & Gardeners 

• Xerces Society’s  Native Plants for Pollinators & Beneficial Insects: Maritime Northwest

 

If you’re looking for seed mixes without invasive seeds, many local environmental groups also sell their own seed mixes, free from invasive plants! Check out the Invasive-free Wildflower Mix created by the Sea to Sky Invasive Species Council. For more larger plants, our colleagues at the Fraser Valley Conservancy also holds a Native Plant Sale every year!