Better Together: How Plant Diversity Supports Garden Health

Earth’s biodiversity, the diversity of life across all levels, is on the decline. Animal and plant species face extinction at a rate far surpassing the natural pace. Biological diversity acts as a safeguard against declines in ecosystem functioning. Recognizing and comprehending local environmental issues catalyzes taking action to preserve native and vulnerable plant and animal species. 

In part three of our Program Priority Series host Erin Hoover discusses Plant Biodiversity.
In this episode, Erin covers:

• How do master gardeners support plant biodiversity?
• What does plant biodiversity mean and why is it beneficial?
• Ecological gardening and plant biodiversity
• Plant diversity through the concept of right plant, right place
• Increasing biodiversity with native plants
• Avoiding invasive species when planning for plant diversity
• Sustainable garden choices to support plant diversity
• Ideas for incorporating plant biodiversity in urban spaces
• Top 5 actions gardeners can take to support plant diversity

As a homesteader, Erin has turned her own property into a small, thriving farm. She grows veggies, tends to fruit trees and shrubs, and raises livestock, all while following permaculture principles to keep things as sustainable as possible. Her focus these days is on finding new uses for native plants, figuring out ways to feed her animals from her land, and growing her own food.

When she’s not working on the homestead or recording The Evergreen Thumb, you’ll find Erin out exploring Washington’s mountains, forests, and beaches—always looking for ideas and inspiration to bring back to her garden.

• WSU Master Gardeners Program Priority: Plant Biodiversity
• WSU Master Gardener Plant Biodiversity Tips
• Enhancing Plant Biodiversity for a Vibrant, Thriving Ecosystem
• Washington Native Plant Society
• Plant Sales
• Educational Events
  

Welcome to The Evergreen Thumb, your go-to podcast for up-to-date research-based horticulture and environmental stewardship knowledge to help you grow and manage your garden. Produced by Washington State University Extension Master Gardener Volunteers and brought to you by the Master Gardener Foundation of Washington State.

[00:00:16] I’m your host, Erin Hoover, a WSU Extension Master Gardener since 2015 and a certified permaculture designer and modern homesteader.

WSU Master Gardener volunteers are university-trained community educators who have been cultivating plants, people, and communities since 1973. Are you ready to grow? Let’s dig into today’s episode.

Welcome to episode 45 of The Evergreen Thumb.

WSU Extension Master Gardener Program Priority #3: Plant Biodiversity

[00:01:00] This is part three in our nine-part series on the WSU Extension Master Garden Program Priorities. And this episode is all about plant biodiversity. Earth’s biodiversity is declining rapidly with species facing extinction at an accelerated rate.

Biodiversity is crucial for maintaining ecosystem health. Understanding local environmental issues can inspire actions to preserve native and vulnerable species. Practices such as reducing lawns, managing invasive plants, and promoting native plants help support biodiversity from individual backyards to broader regions.

How Do Master Gardeners Support Plant Biodiversity?

WSU Extension Master Garden Program sustains biodiversity by teaching stewardship of healthy ecosystems and controlling invasive species. These efforts empower individuals to help safeguard ecosystem functioning, enhance biodiversity, and promote environmental stewardship by teaching individuals how to make impactful changes in their homes, landscapes, and gardens.

[00:02:00] The program contributes to cleaner air and water, healthier soils, and more resilient local ecosystems. This, in turn, supports public health, food security, and overall community well-being.

Does Plant Biodiversity Mean?

Plant biodiversity refers to the variety and variability of plant life in a particular area. This includes everything from trees and shrubs to grasses and wildflowers, even ground covers and aquatic plants.

It’s not just about the number of species, but also the genetic diversity within those species and the ecosystems they create. Plant biodiversity is critical for maintaining ecological balance because different plants play unique roles in supporting life. They form the base of food webs. They regulate water cycles, stabilize soil, and provide habitat and food for other organisms like pollinators, birds, and beneficial insects.

Benefits of Diverse Ecosystems

[00:03:00] A wide variety of plants means more food and shelter for wildlife. Native plants in particular have co-evolved with local insects, birds, and mammals, making them essential. For wildlife to thrive, a diverse garden can attract and sustain a wide range of beneficial creatures helping to maintain a healthy ecosystem.

A diverse species of plants also contribute to soil health in various ways. Some fix nitrogen, others hold organic matter like leaf litter, or their root systems help prevent erosion or improve water infiltration, and all of these lead to healthier, more fertile soils. Additionally, plant diversity helps gardens better adapt to stress, such as extreme weather, events, pests, and diseases.

[00:04:00] When you have a mix of species, it’s less likely that a single pest or disease will wipe out everything. Diversity also means that if one plant fails in a drought or a flood, others may thrive, keeping the ecosystem functioning.

Public places like parks and community gardens can also serve as critical biodiversity hubs, especially in urban areas.

Supporting diverse plant life can even address big environmental issues like climate change, diverse plantings, capture more carbon, reduce erosion, and can, like I mentioned, withstand more extreme weather events. A continuous supply of blossoms from a variety of plants blooming at different times helps nourish pollinators throughout their life cycles, and gardens can also act as stepping stones to connect fragmented habitats, especially in urban areas, allowing pollinators and other wildlife to thrive.

Ecological Gardening and Plant Biodiversity

So one concept that relates to plant biodiversity is ecological gardening. In a lot of ways, this is very similar to, um, what I’ve talked about before about the basics of like a permaculture system. And the idea is to design gardens to work with nature rather than against it and supporting those natural processes.

[00:05:00] So like in a food forest or even in, um, ornamental bed, think about layering ground covers, herbaceous perennials, shrubs smaller the understory trees and if you have the space, larger overstory trees and vines and you know, embracing your moss and the lichens and things like that. All these things are natural layers and mimic natural ecosystems to help provide more diverse habitats.

Plant Biodiversity Through the Concept of Right Plant, Right Place

Another concept that Master Gardeners are specifically passionate about is right plant, right place. What this means is when you’re choosing a plant or you’re gonna put a plant in, you know, by your house or in your garden, you want to make sure that you’ve chosen the right plant for that location.

[00:06:00] Things to consider are the lightning. Does it need full sun? Does it thrive in shade? Can you be an edge plant? Work at some sun and some shade? What kind of soil does it need? Does it need sandy well-draining soil? Does it need clay soil that can really hold onto some of that moisture? You need to match plants to the soil type.

Another huge thing to consider is the space. Don’t expect that if the plant tag says that your tree is gonna grow 20 feet, it doesn’t stop growing at 20 feet. That’s what it’s considered its mature size, and the general rule that I use is to add at least 25% to the listed size to better accommodate that plant.

[00:07:00] If it does get too big in the space that you’re trying to allocate for it, that overcrowding with neighboring plants can lead to poor airflow disease and competition for resources. Another thing to keep in mind is the water requirements of the plants that you’re putting in. Are they drought-tolerant? Are there moisture-loving that can affect where you choose to put those plants?

If you have a plant that’s more, uh, sensitive to moisture levels, you know, you may wanna put it closer to your house or in a place where you’re going to see it on a regular basis so that it can get regular water. Whereas drought tolerant plants you can put out much further because they don’t need as much attention and as much water.

Also, consider microclimates in your garden wind exposure. Cold spots like frost pockets, heat sinks, or that like concrete or asphalt areas or other heat reflective areas like uh, rock walls. Those are heat reflective areas, and those are gonna create warmer microclimates where you can maybe push the boundaries of your hardiness zone and protect some more frost sensitive plants.

WSU Extension Master Gardener Plant Sale Reminder

[00:08:00] I wanted to take a quick break to remind you that spring is just around the corner, and this means that it’s time for the WSU Extension Master Gardener Plant Sales across Washington. These plant sales are the perfect place to find healthy, locally grown plants, including vegetables, perennials, natives, and more, all while supporting research-based gardening education in your community.

Not sure where to find a sale near you? Visit your local WSU Extension Master Gardener website or check out the statewide event calendar at www.mastergardenerfoundation.org/overview/plant-sales. Whether you’re looking for the perfect addition to your garden or just wanna chat with knowledgeable gardeners, don’t miss out.

Support your local master gardeners and grow something great this season.

Increasing Plant Diversity with Native Plants

[00:09:00] Another technique to support biodiversity is to include native plants. Now, I know some people are very particular and they say you need to rip out all your non-native plants or whatever. But really, if you’re gonna add new plants or if you’re gonna remove some, consider replacing them with native plants.

Native plants are those that occur naturally in the region where they’ve evolved. That’s kind of what I’ve alluded to earlier. Native plants are going to be more resilient. They’re gonna support other native species of pollinators and other wildlife because they’ve co-evolved.

And one little tidbit that I just read was from, uh, Doug Tallamy, who is an entomologist, who has written a number of books that are an excellent read, if you have a chance.

His research has shown that native oak trees and where I live, there are a lot of the, the gary oak, which is the, or the Oregon white oak. Those trees support over 500 species of caterpillars. That’s huge.

[00:10:00] I didn’t even know we had 500 species of caterpillars, whereas something like a ginkgo tree, which is a beautiful tree, and it’s common in Asia, is host to only five species of caterpillar, and apparently, it takes 6,000 caterpillars to raise one brood of chickadees, a native bird in our region. So this kind of illustrates the impact that planting or supporting native species, a native tree can have an effect on other birds, insects, and other plant life.

Some of the other great things about native plants is once they’re established, they generally don’t require much maintenance. If you want some fancier or special plants, like I said, you know, keep those closer to the house or closer in an area where you’re going to be regularly so they can get the most care.

[00:11:00] But native plants are generally tougher, especially if they’ve been grown in a native plant nursery in your local area. Now if you go buy a douglas fir that was grown in Michigan and you live in Washington, it’s gonna be more acclimatized to Michigan. You know, so it’s not exactly the same, um, even if it is the same species because native plants are adapted to local environments, they require a lot less water.

Um, like what I said before, but this also saves you time because you’re not out there watering everything. They save water, um, and it saves you money, especially if you’re on a municipal water system and you have to pay for your water.

Avoiding Invasive Species When Planning for Plant Biodiversity

[00:12:00] So another aspect of our plant biodiversity program priority is invasive species, particularly invasive plant species, although there are invasive insects as well that are a problem. So, educating yourself on what are the invasive species in your area, because it varies from county to county, and from Eastern Washington and Western Washington.

There’s a state list, and then each county has its own list of different classes of obnoxious weeds and which ones need to be controlled. So check with your noxious weed board to make sure that you are not supporting or introducing invasive species into your landscapes. Butterfly bush is one shrub that gets a lot of controversy because they tend to propagate very easily and spread, and I.

Supposedly they’ve created sterile species, but I’ve heard that there may be some issues with that as well. I don’t have any concrete evidence on that one. People say they like to plant them for the caterpillars, but most caterpillars and butterflies and monarchs in particular, don’t actually use butterfly bush.

[00:13:00] Butterfly bush apparently do provide nectar to some adult butterflies, but because of their potentially invasive nature, there are a lot of other options that are a better fit. Native milkweeds are another option.

Butterfly bush is actually a Class B invasive species in Washington, and uh, that means that it is currently limited to only portions of the spa, but it is required to be controlled in regions where they’re not yet widespread and that’s where you need to contact your county Noxious Weed Board to learn if, if they do need to be controlled on your land. The big problem with what are classified as invasive species is that they outcompete native species and can actually, in some cases damage ecosystems.

[00:14:00] There are some plants like, uh, yellow flag iris, that grow in marshes and riparian zones and can actually prevent access, wildlife access to the water because they’re so thick. They can create a lot of problems with the flow of water, things like that.

Sustainable Garden Choices to Support Diversity in the Garden

So next I wanna talk about some of the more sustainable gardening choices that you can make to support plant biodiversity.

And one of them is to plant with future generations in mind. Think beyond a single season, choose perennials, whether they be herbaceous, meaning they die back all the way to the ground each winter, or self-sowing annuals are another nice one, and you could also try getting involved with seed-saving or propagating plants.

You already have them so dividing them, taking cuttings. And we do have an episode on seed saving primarily for vegetables. But there are some native plants that are very, very easy to propagate on your own.

[00:15:00] And then also is, you know, educate others, sharing knowledge. If you do research on an invasive species, share that knowledge, and that’s one of the things that really important to master gardeners is master gardeners are lifelong learners, and it’s our purpose to educate others on how gardening choices can impact the environment, impact biodiversity.

Ideas for Incorporating Plant Biodiversity in Urban Spaces

So what are some ways you can incorporate biodiversity into small spaces or urban spaces? And it is possible no matter how small a space you have. You might consider a small container garden. It can be just a small raised bed. It could be a container like a pot in a windowsill or on your patio.

[00:16:00] Have a diversity of plants in a variety of pots, pollinator strips, sidewalks, or fences. And if you choose a pollinator seed mix, try to make sure that all of the plants listed in the seed mix are native. There are some seed mixes that are come from other parts of the country and may contain plants that are very aggressive in this area, even if they aren’t necessarily, uh, considered noxious weeds.

So keep that in mind. One thing that I’ve actually found very beautiful is in, in more, um, urban or suburban neighborhoods where there’s that strip between the sidewalk and the, and the road. There are all kinds of names for it, but turn that into a pollinator garden or a kind of a rain garden if it’s on a hill or on a slope, you can do a dry riverbed or plant appropriate plantings in there for pollinators.

[00:17:00] And there’s a lot of ways to support biodiversity in small spaces or even just if it is a large space, start small. Just do a section. Do what your time and experience and space allow, observe nature. That’s been a big one for me is observing nature. Learning how to see the layers in a forest and mimic those in my own garden and expanding over time.

You don’t have to do it all right away. You don’t have to rip out everything that’s non-native. Work with what you have and take those things into consideration as you go.

Top 5 Actions Gardeners Can Take to Support Plant Diversity

Okay, so here I’m gonna talk about the top five actions that gardeners can take to support biodiversity. These are some of these I’ve already talked about, but just kind of to recap them.

Incorporate natives into your gardens to support local wildlife. Avoid invasive species that harm ecosystems, diversify plantings by mixing species colors and bloom times. This is especially good for pollinators. Create habitats, include water, shelter, and food sources for birds, insects, and other wildlife.

[00:18:00] Finally, share. Share your knowledge, share seeds with friends and neighbors and community groups. I know a lot of libraries actually now have started seed banks and seed libraries. Where I am it’s the Timberland Regional Library.

There are several libraries in that system that have started seed libraries, and I know our main group, the Master Gardener Program that’s local to me, we have a seed saver event every fall in our demonstration garden where we share the seeds that we harvested from the plants in the garden. And there are many other master gardener groups that do that as well. So, check with your local extension office or your local Master Gardener Program to see, um, what kind of seed-saving events or workshops they offer so that you can share and learn more.

Final Thoughts

That more or less wraps this up, but I want to encourage you to explore resources on the WSU Extension Master Garden Program website.

[00:19:00] There’s a webpage that I will share in the show notes that links directly to our plant biodiversity program priority and talks about not just the impact that master gardeners have, but what you as gardeners can do.

I’ll also include some other podcast episodes that I’ve done in the past related to plant biodiversity, and if you have any specific questions about plant biodiversity or if you want to share some photos of your experiences in building biodiversity in your garden, find us on social media. We’re on Instagram and Facebook, and we’d love to hear from you.

Or you can always email me at hello@theevergreenthumb.org. Thanks for listening.

[00:20:00] Thank you for joining us on this episode of The Evergreen Thumb, brought to you by the WSU Extension Master Gardener Program volunteers and sponsored by the Master Gardener Foundation of Washington State.

We hope that today’s discussion has inspired and equipped you with valuable insights to nurture your garden.

The Master Gardener Foundation of Washington State is a nonprofit organization whose primary purpose is to provide unifying support and advocacy for WSU Extension Master Gardener programs throughout Washington State.

To support the Master Gardener Foundation of Washington State, visit www.mastergardenerfoundation.org/donate.

Whether you’re an experienced Master Gardener or just starting out, the WSU Extension Master Gardener program is here to support you every step of the way. WSU Extension Master Gardeners empower and sustain diverse communities with relevant, unbiased, research-based horticulture education.

Reach out to your local WSU Extension office to connect with master gardeners and tap into a wealth of resources that can help you achieve gardening success.

[00:21:00] To learn more about the program or how to become a Master Gardener, visit www.mastergardener.wsu.edu/get-involved.

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The views, thoughts, and opinions expressed by guests of this podcast are their own and do not imply endorsement by Washington State University or the Master Gardener Foundation of Washington State.