Sow Seeds Now for Spring Blooms

Amy L. Dabbs,
Clemson University Cooperative Extension Service

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As I left the house for work this week, an acorn fell on my head, a sure sign of the arrival of autumn. Many flowering shrubs and perennials have already flowered and produced seeds throughout my garden, a fact that I have tried to ignore as summer wanes. Even though I will miss summer, the bright side is that many of the perennials that I love can be propagated from these free seeds.

Many popular flowering perennials produce copious seeds at the end of the growing season, a strategy developed for ensuring survival of their species. Seed dispersal by wind, water, animals or exploding seed pods helps spread potential new plants into the larger world where at least some of them will grow to maturity.  

Gaillardia x grandiflora ‘Arizona Sun’ flowers and mature seed heads.
Gaillardia
x grandiflora ‘Arizona Sun’ flowers and mature seed heads.
Joey Williamson, ©2015 HGIC, Clemson Extension

As seeds land on garden soil at the end of summer they are prevented from sprouting prematurely because they are in a state of dormancy inherited from the parent plant. This genetic programing ensures that germination occurs only under certain environmental conditions, another failsafe for improving the chances of surviving to flower another year. 

Perennial Blackeyed Susans (Rudbeckia fulgida) are easily propagated by seeds. If seed heads are left in the garden during the winter, goldfinch will feed upon the seeds.
Perennial Blackeyed Susans (Rudbeckia fulgida) are easily propagated by seeds.
If seed heads are left in the garden during the winter, goldfinch will feed upon the seeds.
Joey Williamson, ©2015 HGIC, Clemson Extension

Specific combinations of warm or cool temperatures, moist or dry conditions and darkness or exposure to light unlock the tiny plant within each seed.  Some of the combinations are simple as in most vegetables and annual flowering plants, which generally only need their seeds to dry out completely before becoming inundated with moisture again to cue germination. It can be somewhat trickier to grow perennials from seed and may take a year or more for a seed-grown perennial to produce flowers.

Native scarlet beebalm (Monarda didyma) attracts and is pollinated by butterflies and hummingbirds.
Native scarlet beebalm (Monarda didyma) attracts and is pollinated by butterflies and hummingbirds.
Joey Williamson, ©2015 HGIC, Clemson Extension

While perennials are not as simple to grow from seed as annuals or vegetables, gardeners have discovered various strategies for overcoming seed dormancy by mimicking Mother Nature.  These horticultural ‘tricks’ allow gardeners to plant in narrow timeframes maximizing flower power in their gardens. 

Perennial seeds purchased for spring planting often include directions for providing a “cold treatment” or cold stratification period prior to germination. This typically involves placing seeds in a moist peat based potting media stored in the refrigerator for a prescribed period of time prior to planting in the garden. This is a great way to overcome seed dormancy and ensure flowering in the same planting year. 

An even easier method is to plant seeds directly in the garden in fall, allowing winter weather to naturally break dormancy for seeds that require a cold treatment. Not all perennials that produce seed can be propagated this way. If in doubt, researching individual plant propagation techniques is easier than ever.

The native butterflyweed (Asclepias tuberosa) prefers drier sites and attracts Monarch butterflies.
The native butterflyweed (Asclepias tuberosa) prefers drier sites and attracts Monarch butterflies.
Joey Williamson, ©2015 HGIC, Clemson Extension

Perennial Clematis 'Etoile Violette' produces large purple blooms.
Perennial Clematis 'Etoile Violette' produces large purple blooms.
Joey Williamson, ©2015 HGIC, Clemson Extension

Start by examining plants you may already have that have produced seeds. A few garden favorites that are well suited for fall seed sowing include:

Purple coneflower (Echinacea spp.)
Black-eyed Susan (Rudbeckia spp.)
Penstemon species and cultivars
Blanket Flower (Gaillardia spp.)
Butterfly weed (Asclepias spp.)
Bee Balm (Monarda spp.)
Upland Sea Oats (Chasmanthium latifolium)
Hardy hibiscuses
Clematis spp.
Sea Holly (Eryngium spp.)

Note that hybrid perennials may not be true to type when planted from seed, but it is certainly worth a try to see what sprouts! 

Be sure to follow good seed planting practices prior to planting collected or purchased perennial seeds. Create a competition-free seedbed by clearing weeds from the area to be planted. Avoid tilling. Only disturb the soil enough to ensure good seed to soil contact, but do not dig deeply enough to bring weed seeds to the surface. Broadcast seeds over the entire area to be planted rather than in regimented rows to create a cottage garden feel for your perennial bed or border. 

After scattering seeds, lightly press into contact with soil. Stepping on prepared soil can compact it. Instead, place a wooden board over larger areas and step on the board. Only mulch very lightly with pine straw or chopped leaves if you must cover the area, but otherwise leave uncovered for best germination rates.

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