When’s the Best Time to Plant Wildflowers from Seed?
If you’re dreaming of a colorful wildflower patch buzzing with pollinators, you may need to get a head start on planting. Garden expert Logan Hailey digs into the proper timing for wildflower seeding in the garden!
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Not every part of your garden should be manicured and domesticated, especially if you want to nurture wildlife like bees, butterflies, and birds. Wildflower plantings add beautiful, low-maintenance color and dimension to your garden while providing vital habitat for local creatures.
Unlike vegetables and ornamentals, wildflower seeds typically do best with very little attention. As long as they are direct seeded at the right time and depth, nature does most of the work for you.
It’s important to source wildflower seeds native to your region and climate. Native plants have adapted for centuries or millennia to the specific soil, rainfall, and temperatures of your area. But before you can bring your wildflower dreams to life, be sure you plant the seeds at the right time or season for proper germination and growth.
Featured Seeds In This Article:
The Short Answer: Autumn is Ideal for Sowing Most Wildflowers
Generally, fall (September to November) is the best time to sow perennial wildflowers because it ensures the plants are in sync with Mother Nature. While every species has slightly different needs, most temperate wildflowers bloom in summer and drop their seeds in fall. Fall seeding between September and late November mimics the lifecycle of these wild plants.
Winter moisture and frosty temperatures help the seeds break dormancy and trigger strong growth in spring. Then, the new plants emerge, and the cycle repeats, creating self-perpetuating wildflower patches. However, this time frame varies depending on where you live and whether a plant is annual, biennial, or perennial.
Tender annual wildflower seeds like zinnia or native sunflowers should be seeded after your last frost date when the soil temperature is at least 55°F (13°C). Biennial and perennial wildflowers like echinacea (coneflower) and yarrow should be planted in fall to ensure that cold temperatures break the seed dormancy.
The Long Answer
Many wildflowers require a vernalization (cold exposure) period to break the seed’s dormancy and trigger germination. Take note of the flower species’ lifespan and native region. For example, Texas bluebonnets can be seeded as late as October to mid-November in Texas, while goldenrod (Solidago spp.) can be sown throughout the winter in far northern climates. Tender annuals like zinnias shouldn’t be seeded until the warm weather of spring.
However, for most temperate-climate species, seeding in fall mimics the flowers’ natural lifecycle. Wildflowers that bloom in late spring and summer typically set fruit by late summer or fall and develop ripe seedpods. Before frost arrives, these fruits or pods will fall to the ground, leaving seeds to overwinter before sprouting and growing again in spring.
Sow Biennial and Perennial Wildflowers in Fall
In general, almost all biennial and perennial wildflowers are seeded in the fall or very early spring. This allows the seeds to sit through the cold temperatures of winter and germinate as soon as the weather warms in spring.
If you forget to seed in fall, you can also broadcast sow (scatter) wildflower seeds as soon as the ground is free of snow in spring. Those in more temperate climates can seed in winter. Some flowers can even be sown in the snow!
Wildflower Seed Cold Stratification
Cold exposure is the key to most wildflower success in temperate regions. If a plant is accustomed to growing in areas that frost (most of the U.S.), it will likely require cold, moist weather to “awaken” them and trigger germination. Seeds remain dormant or “asleep” until this happens.
Cold stratification is sometimes called “vernalization” or “cold treatment.” All these terms mean the same thing: the seeds need to be exposed to cold weather to germinate.
If you live in an area that doesn’t freeze, your local native wildflowers typically won’t require a cold exposure period. However, if you want to grow flower seeds that require vernalization, you can place the seeds in the fridge for several weeks or multiple months before planting. This is a way to expose them to “winter” in a simulated environment.
Sow Tender Annual Flowers in Early Fall or Late Spring
If you miss the fall planting window, it’s best to wait to plant annual wildflowers until spring when the risk of frost has passed and soil temperatures are above 55°F (13°C). Tender annual flowers cannot handle frosty temperatures, so if they germinate too late in fall, the fragile young foliage will likely die during the coming frosts.
Harsh northern winters can also kill the seeds, inhibiting germination altogether. Your wildflower seed packet should tell you if you’re dealing with a tender annual.
Annual vs. Biennial vs. Perennial
The lifecycle of a plant determines its growth, flowering, and seeding schedule. Humans have divided plants into three categories to describe their life cycles:
- Annual: Complete their entire life cycle (from seed, to flower reproduction, to death) in one season
- Biennial: Grow foliage their first season and produce flowers/seeds the second year
- Perennial: Live longer than two years with persistent roots
Annual Wildflowers
Annual plants live for a single season and die when frost arrives. This means they undergo their entire life cycle (from “seed to seed”) in one season. They germinate in spring, grow their leaves and stems, flower in summer, then mature their seed pods in fall. The seeds fall to the ground and begin a new generation the following year.
Many of our garden vegetables, like tomatoes and cucumbers, are annuals in temperate gardens. Annual wildflowers provide the quickest colorful show, often blooming within 2-3 months of germinating.
Some annuals are cold-hardy and behave like perennials in warm climates. In other words, hardy annuals can withstand cold weather and keep growing. Other annuals are “tender.” Tender means they cannot handle frosty temperatures, and you should wait to plant these wildflower seeds until the weather has thoroughly warmed.
Popular annual wildflower species include:
- Sunflowers (Helianthus annuus)
- Cosmos (Cosmos bipinnatus)
- Red poppies (Papaver rhoeas)
- California poppies (Eschscholzia californica)
- Blue cornflower (Centaurea cyanus)
- Texas bluebonnets (Lupinus texensis)
- Scarlet flax (Linum grandiflorum)
- Zinnia (Zinnia elegans)
An annual begins its life in soil in fall or early spring. The seed germinates when the weather warms and begins growing leaves and stems. The plant then shifts into flowering or reproductive growth. For some plants, a shift in length of sunlight (day length) triggers them to flower. For others (day-neutral plants), they naturally begin flowering at a certain age.
Self-seeding annuals drop their seeds in place and grow new colonies every year. Self-sowing annuals are sometimes confused with perennials because they reappear every year without any effort from the gardener. The reason these plants are still annuals is because they don’t overwinter with the same roots or above-ground plant parts as they had before. The old plants die back, and new plants reappear each year.
Biennial Wildflowers
Biennial plants take two years to complete their lifecycle. If you don’t see flowers the first year, don’t panic. This is normal! The first year, biennials put all their energy into germination and developing their roots, stems, and leaves. This is the “vegetative” growth stage. The second year, biennials shift their focus to producing flowers, fruits, and seeds. This is the “reproductive” growth stage.
Although slower growing than annuals, many biennial flowers bloom for 2-3 months or throughout the entire summer. They tend to prolifically self-seed just like annuals. So as long as you leave the flower heads in the garden, they will naturalize and expand a small colony next year. You can generally plant biennial wildflower seeds in fall or winter.
If you notice that some of your flowers don’t bloom during their first season, it may be because they are biennial, and their genetic code tells them to wait. Biennial flowers are less common in wildflower seed blends. They include:
- Foxglove (Digitalis purpurea)
- Alpine forget-me-not (Myosotis sylvatica)
- Black-eyed Susan (Rudbeckia hirta) *some behave as short-lived perennials
- Standing cypress or Texas plume (Ipomopsis rubra)
Garden vegetables like kale and cabbage are technically biennials because if you leave them over winter, they will go to flower the following year. But most of us harvest them before they get the chance to do so.
Perennial Wildflowers
Perennial plants live for longer than two seasons, returning year after year with new blooms from the same plant. Perennials grow the slowest but last the longest. Woody perennials like lavender or sage produce tough stems that get larger every year.
However, most wildflower species are herbaceous perennials that die back to the ground and overwinter using their roots. It may look like they are dead, but they will resume leaf growth from the same roots in spring as long as a disease or pest hasn’t killed them.
Native perennial wildflowers are the best choice for a long-lasting, colorful ecosystem of flowers that returns year after year with very little effort. They are particularly important for pollinator plantings and butterfly gardens because local insects have evolved close symbiotic relationships with those species.
Great perennial native wildflowers include:
- Anise hyssop (Agastache foeniculum)
- Blazing star (Liatris spicata)
- Blanket flower (Gaillardia spp.)
- Black-eyed Susan (Rudbeckia hirta)
- Beardtongue (Penstemon digitalis)
- Blue false indgio (Baptisia australis)
- Blueflag iris (Iris versicolor)
- Cardinal flower (Lobelia cardinalis)
- Coneflower (Echinacea purpurea)
- Green and gold (Chrysogonum virginianum)
- Milkweed (Asclepias spp.)
- Moss phlox (Phlox subulata)
- Monarda or beebalm (Monarda spp.)
- Goldenrod (Solidago spp.)
- Shasta daisy (Leucanthemum spp.)
- Yarrow (Achillea millefolium)
Perennials are sometimes separated into two categories:
- Short-lived perennials: Live shorter than 5 years
- Long-lived perennials: Persist from the same roots for 10+ years, up to several decades
In a wildflower patch, this differentiation is only important because you may notice some perennials producing fewer flowers as they age. As long as the seeds are left to self-sow, you shouldn’t need to plant them again. However, if you harvest the flowers for drying or bouquets, the plants won’t self-seed, and you may need to propagate them yourself.
Remember, you should plant perennial wildflower seeds in fall so they can undergo the crucial cold exposure period to germinate!
Native vs. Non-Native
If you dream of an ecologically beneficial wildflower oasis filled with buzzing bees and butterflies, native flowers are the best choice. These species are adapted to your region, and local wildlife already use their nectar and pollen. Planting native species is very helpful in areas where wildlife habitat has been eliminated, such as in cities and suburbs.
Some wildflower seed blends include non-native species from different states or countries around the world. They can also include domesticated and hybridized flower species that were bred for specific aesthetics yet aren’t actually from your region.
I believe calling them “wildflowers” is incorrect because “wild” implies that these flowers grow naturally in your area. If you are importing them from somewhere else, they are not technically “wild” where you live. These plants aren’t necessarily harmful, but they won’t offer the same natural preservation and pollinator support as a native wildflower species.
For the lowest-maintenance and most ecological planting, I recommend sourcing native wildflower seed blends formulated for your specific region.
Seed Wildflowers Shallowly
Seed depth is a final generalization that is helpful for growing wildflowers. You shouldn’t plant these seeds deep into the soil. Most wildflower seeds need light to germinate. Again, this mimics the natural lifecycle of the plants.
Wild plants don’t dig holes to bury their seeds; they simply drop them on the soil surface and leave them to germinate on their own! Don’t bury your wildflower seeds unless it is explicitly stated on the seed packet.
Most blends can be broadcast or scattered on the soil surface and watered in. If you want to protect them from blowing away, lightly press into the soil or cover them with a very fine layer of vermiculite or compost, but avoid burying them too deep!
Final Thoughts
Most wildflower seeds should be planted in fall, between late September and mid-November, before heavy frosts occur. The cold and moisture of winter will help break seed dormancy so they can germinate and take off growing in spring. Don’t plant them too deep, as this can inhibit germination.
Remember to choose native wildflower species that are endemic to your region! This means they can take care of themselves without any maintenance while providing crucial nectar and pollen resources to local wildlife.
