While our main focus is on growing things that we can eat, that necessarily includes providing conditions for all of the living things who form part of the food web that we and our food exist in.
We realize that first sentence is a bit of a word salad, so let's break it down.
In order to survive, all living things rely on the interaction of countless other living things in their environment. Some of those things have direct relationships - like how an apple tree needs pollinating insects and a genetically different apple tree nearby in order to set fruit. The vast, vast majority have indirect relationships - like how certain soil microorganisms interact with humic acids and permit certain elemental minerals to bond with soil particles to make the minerals available for absorption through plant roots. Every living thing has multiple direct and indirect relationships, spreading outwards in all direction. The combination of all of those relationships is so mind-bogglingly complex that we humans aren't even close to understanding how the most basic of natural processes actually work. That network of relationships is the food web.
Kind of makes you long for the good ol' days when we thought it was a food chain, eh?
So what does this have to do with flowers? Well, the selfish answer is: pollinators. At its most basic level, the more different types of flowers we have, blooming at different times of year, the more we encourage pollinators - bees, butterflies, moths, wasps, flies, ants, beetles, birds, and all sorts of other delightful critters - to hang around. That way they'll be here when our food crops are flowering. Of course, the food web has a lot more layers than that. A better answer is that bugs are a key indicator of ecosystem health. Pollinators are only a small subset of the general insect population. Among insects, there are herbivores, predators, scavengers, and decomposers, each playing an important role - despite humans often viewing them as problem pests. Bugs are the primary food source for birds and small mammals, and vital for ecosystem health.
Our flower focus is on perennials and self-seeding annuals - flowers that come back bigger, stronger, and in greater numbers year after year. We're saying flowers, but we really mean perennials of all types - trees, shrubs, vines, herbaceous plants, ground covers, and grasses alike. Year over year, our flower gardens take over more and more of the acre of lawn that was here when we moved in. We're dedicated collectors - adding more and more different species and cultivars to the mix.
Without Pearly Everlasting in the garden, there's no food for the Painted Lady caterpillar. (Photo courtesy of Natural Themes Native Plant Nursery)
A diversity of perennials creates a diversity of food sources and habitat, which attracts a diversity of species. Most insects are specialists - particularly the herbivores - they have one specific host plant upon which they can feed, or hatch their young. As goes the plant, so goes the insect.
An abundance of insects attracts an abundance of predators. Predatory insects - like wasps, ladybugs, and dragonflies - tend to overwinter their eggs in or on perennials, especially those with hollow stems. Perennials tend to put on seed heads or fruit which hangs well in to the winter months, feeding birds and small mammals who overwinter here, and the migrators who arrive early or leave late. The stems and leafy debris of last year's growth provides overwintering, breeding, and hiding spots for amphibians and reptiles. When we give them a place to live, these predators repay the favour by patrolling our gardens 24/7.
There's way more going on below ground than above it. Perennials drive the creation of topsoil from sand, clay, and rock. Their roots reach deeper and wider than annual plants, and are a habitat for billions upon billions of soil micro-organisms. Every fall, when the leaves fall or the plant ties back, some of the roots die off too. Those roots decompose, which feeds soil life, sequesters organic matter (carbon) and bio-available minerals, and leave empty spaces in the soil which hold water. Each growing season, the plants and micro-organisms work together to take carbon and nitrogen from the air and store it in the earth, to break minerals out of rock and clay particles and incorporate them into living tissues (where they become available to whoever eats the plant). Annual plants do these things too, but not nearly as well, or as quickly, and take a lot more human effort to maintain. Only perennials can create a stable soil ecosystem that builds rich, spongy topsoil with minimal human input.
The foliage of Sundrops feeds Momphid moth larvae, and their pollen supports a native bees and moths. (Photo courtesy of Natural Themes)
So yeah, we plant a lot of flowers... but not all flowers are created equal. Some are more equal than others.
New England Aster is a keystone flower, which hosts 9 species of caterpillar, and is the sole food source for 16 specialist pollinators.
Native plants are vastly superior to non-native plants. We're lucky to have Natural Themes Native Plant Nursery about 10 minutes away, so it's easy for us to get advice, nursery stock, and seeds. The question of what's "native" and what's not can be a bit of a hot-button issue for opinionated gardeners. Few would debate the merits of native plants - planting the plants who adapted to live here to support the critters who co-evolved with them. It's really a no-brainer. Where you get disagreement is over what's "native", the impact of climate change, the naturalization of "invasive" species, and whether we should be planting "exotics", "non-natives", or "invasives" at all.
In short, the problem with non-native species is that no bugs here evolved to eat them. This may be great for having pristine, undamaged foliage in your garden, but if nothing is eating them, then you've planted a food desert for bugs. True, many exotics are, when in bloom, popular with pollinators - and it is important to provide pollen and nectar for the flower-feeders. The problem is that almost all pollinator insects start off their life as an herbivore. Eggs are laid on a host plant, and once the young hatch, this plant is their food source. 90% of insects are only capable of eating one plant. This is true at the herbivore stage, and at the flower-feeding stage. A few insects can feed on plants in the same family, but most insects evolved only to eat one thing. If that plant is absent, so too is that insect. If that insect is absent, then its function in the ecosystem is unfulfilled.
The more gaps in ecosystem function you have in your yard, the the more dysfunctional it is. A dysfunctional yard is out of balance, and prone to infestations and outbreaks. When you group a bunch of dysfunctional yards together, you've built dysfunctional neighbourhoods and cities. Enough of those adds up to a sick ecosystem, and accelerates biodiversity collapse, just like we're seeing.
A diversity of native plants is the only cure.
It's critical to feed as many different kind of bugs as we can, through their full life cycle. It's a remarkably easy thing to do. Just plant a bunch of different native plants.
So what's a native plant then?
The short answer is that a native plant is one that evolved in the place you are. We've heard a lot of people describe their definition of "native", and they're all pretty good. We don't take sides, or pass judgement if someone has a different definition than us. The fact that they've taken time to think about what it means to them, and come up with their own definition at all puts us all on the same team. For us, we have a really broad definition: anything that originated in north-eastern North America, and maintains its place in the food web is good enough for us.
North-eastern North America is a big, and very diverse area to draw from. North is our starting point - as with our edible perennials - is the growing zone. We're Zone 5 here, in the "Great Lakes Forest" bioregion. We've started with edibles that grow well in our zone, but usually to Zone 4 - which gives us the best chance of the plants surviving winter. Once we're more established, have identified some warmer microclimates, and have some time to play around on the margins, we'll venture into Zone 6 and warmer. In 50 years, our area will likely be more of a Carolinian climate, due to global warming. We will have warmer climate plants here waiting for it. Same idea with the flowers. East is the next element. Our bioregion was historically mixed forest, dominated by white pine, oak, maple, black walnut, beech, cedar, and hemlock. It stretches from the Atlantic Ocean in the east, to the prairies in the west. If it evolved in that environment, it's native enough for us.
That settles the question of where a plant originates, but its place in the food web is equally important to us. It matters what humans done with or to the plant. There's a spectrum of human
Bloodroot is one of the earliest flowers, and provides a critical spring food source for solitary bees, flies, and beetles. Its seeds are spread by ants.
involvement, from plants that have made their own way on one end, through selective breeding (propagating the offspring of the plants that are most like what we want), to backcrossing (combining two or more plants that have the characteristics we want), all the way to genetically modified frankenplants on the other. The farther you get away from the self-evolved plant, the more likely it is that you're removing connections to the food web.
Plant breeders, particularly for commercial nurseries, tend to select for things like colour, bloom size, bloom length, disease resistance, cold hardiness, drought tolerance, ease of harvest, and so forth. These "improved" varieties are called cultivars. Cultivars can be beautiful, bulletproof plants in the garden. The problem is that they've often been changed faster than the rest of the food web can adapt. Nothing co-evolved with them. Cultivars of native plants are more useful than cultivars of exotics. But even native cultivars are less useful than their source plant. They tend to host fewer micro-organisms in their roots, provide less nutritious pollen or nectar, or even be inedible to the single-host species who rely on the parent plant for food, and so on. Sometimes the usefulness of a plant is plain to see from the bites out of the leaves, or the swarms of flower feeders covering the blooms. However, the vast majority of ecosystem impacts are unseen, unstudied, and unknown. That's why many native plant lovers are hard-liners against cultivars and non-native plants at all.
We're not hard liners. We love us some crazy double-frilly-giant tulips, a massed bed of hostas, or a unique colour of creeping phlox. It's virtually impossible for Mike to drive past an end-of season garden centre sale without ripping a U-ey. We're collectors of all kinds of beautiful plants, and a few ugly ones. In our gardens, native wildflowers stand side-by-side with cultivars of the same plant. We aim to have at least 50% of our planted gardens be native plants or cultivars. We make up for the exotics with sheer volume. Our farm is 36 acres, and is already abundant with wildflowers. We plant 50+ native trees and shrubs a year. The previous owners planted a LOT of native flowers, which we propagate into new garden beds. This place positively vibrates with life, in all seasons. We lucky to be able to focus on making relatively minor tweaks to the overall farm ecosystem.
Flower garden priority #1 is lawn reduction. Turf grass is pretty much a monoculture of non-native grasses that are cut so short they're never allowed to flower. The more of that we can replace with a perennial garden, the more habitat we create, the less gas we burn, the less time we spend mowing, and the more beautiful our own habitat becomes. We're still learning about different native species - many of which we'd never seen before - and their growth habits - but the main focus is smothering grass and getting roots in the ground.
In all our plantings, we aim to have a succession of blooms from the earliest days of spring, through to the killing frost in the fall. From fall through winter, seed heads stand in the garden, and berries and nuts hang from the branches for the hardy few who stick out the winter.
Native flowers form the backbone of any new garden planting. We try to plant at least as many natives (as close as we can get to the self-evolved plant) by volume as we do cultivars. Our vegetable gardens are surrounded on all sides by flower gardens with tall, native perennials, to invite predators and pollinators into our garden. Native perennials are sometimes slow to establish, so we'll patch holes with annual plants, or less vigorous self-seeders that will eventually get out-competed. We'll plant native support species in our forest as well. We apply permaculture guilds to our flower plantings too - layering trees, shrubs, vines and herbaceous perennials together - including nitrogen-fixers, and plants with different types of root.
In the years to come, as we get to know these native plants a little better, we plan to share some guides to assembling "guilds" of native plants which feed garden visitors year-round, and how to achieve a "cottage garden" vibe using natives.
Hairy Beardtongue is one of only two larval hosts for the Baltimore Checkerspot butterfly.
Gardening is about the journey, not the destination. Every year, in every bed, we get a little bit better.