Ecology, Economics, or Culture?
What determines your
prairie/savanna seed mix, or…
Why do so few plantings look like this?
Chiwaukee Prairie SNA , Kenosha County, WI
Black Earth Prairie SNA, Dane County, WI
Hagen Road Prairie SNA, Columbia county
with high concentrations of spring flora
… and autumn flora.
Gentiana puberula, Hagen Road
Prairie SNA, Columbia County
Avoca Prairie SNA, Iowa Co., WI
Scuppernong Prairie,
Kettle Moraine South Unit
Oak savanna restoration, Kettle Moraine South Unit
Our State Natural Areas
have high forb diversity,
good representation of
spring blooming taxa and
rare plants.
We expect the quickest rate of return on our
investments regardless of the rate of natural
growth, which is why Ratibida, Echinacea, and
Rudbeckia dominate at the expense of slower growing
species.
The difference between a prairie planting
and a vineyard is that grape vines are easily seen and
recognized at all stages of development, but both mature at
about the same rate.
If a client (or graduate student)
can’t recognize a seedling in the first or second
year, the planting is perceived as a failure…
and the client may go to another vendor!
The most important factors
determining seed mix design:
•
•
•
•
•
1. Fear of Failure
2. Impatience
3. Profit
4. Cost and availability of seed
5. How it compares with other
commercial mixes
The least important factors in a
commercial mix:
• 1. Matching composition of prairie
remnants native to your area
• 2. Limiting seeds per square foot to a
reasonable number
• 3. Balancing mix to favor conservative
species
Wisconsin has many
excellent
references for our flora.
In spite of these excellent resources,
few nurseries use them as a guide for
selecting plants.
Seed mix from Wisconsin
nursery with Echinacea
purpurea, not native
to Wisconsin, planted in
Sauk Co.
Commercial models have
replaced our remnant prairie
models.
Unfortunately, most research and the
papers, books, and articles based on that
research is limited by the same
economic and social forces that dictate
all mixes.
From Proceedings of the Twelfth North American Prairie
Conference, 1992
“Prairies planted on cultivated sites are often not very
diverse … They tend to be predictably
alike: heavily dominated by tall grass and easily
established composites.”
The Tallgrass Restoration Handbook
Basically a true statement, but this result has more to
do with the seed mix than basic plant ecology. We
often confuse economic limits with ecological ones.
Important phrases
(from Tallgrass
Restoration Handbook):
“less adaptable”
“conservative”
“never show up”
“finer seeded, slow growing”
“lost its vitality…or consumed”
Popular prairie restoration ecology:
Blame the plants, not the seed mix!
Your fault,
not ours!
2 year old, maladapted, fine seeded,
slow growing gentian in non-prairie
soil.
A recipe for dominance by warm season
species
Ten years later, however, diversity may
actually decrease. The assumption that
these plantings will become more like our
SNAs with time is false.
Recipe for authenticity: Replicate natural plant
associations, leave out the cheap stuff, be patient!
1989 fall planting, first
bloom in 1993.
2013 photo,
24 years after
planting.
A planting protocol favoring “conservative”
species and one favoring quick results with
aggressive species are mutually exclusive.
In the absence of
competition from aggressive
species, “conservative”
species are no longer
conservative.
However, their cost and
perception as difficult limit
their use in commercial seed
mixes.
Both dropseed (on left) and big bluestem (on right) are
long-term competitors that can persist for decades.
The species that arrives first dominates.
It is easier to establish
“conservative” species
on bare soil, or even
old field and pasture,
than it is to incorporate
them into plantings
already dominated by
tall prairie grasses
without major
disturbance.
Following the ice age, it is probable that dropseed, as well as
many forbs and sedges, being cooler growing than warm
season big bluestem or Indian grass, preceded those species
on our northern grasslands. Theories placing dropseed as
the end result of prairie succession may have it backwards.
The notion that “prairie obligate” species must
have virgin prairie soil to germinate and survive is
not supported by the many plantings
that emphasize conservative species.
This view from the top of a prairie remnant in Columbia
County illustrates why many species are confined to these
remnants: many lack the seed dispersal necessary to
reach suitable habitat managed for their survival.
For example, the prairie lily, (Lilium philadelphicum), has
spread only 200 feet in 20 years from this nursery
planting to an adjacent site managed by mowing for
brush control.
Prairie Enthusiasts and
Madison Audubon
volunteers help collect and
disperse seed from
remnants to new sites.
We have become the
primary agent for
seed dispersal for many
rare species.
The endangered eastern
prairie white fringed orchid.
Hundreds of individuals
colonized a former
corn/soybean field,
establishing one of the
highest populations in
Wisconsin.
Once thought to be an
indicator of virgin prairie,
it can spread and thrive
given a seed source and
newly managed habitat.
A byproduct of
over-specialization in
science is that experts
inadvertently put forth
obstacles to success
that may not exist,
often citing their own
specialty as the limiting
factor, either unaware
of or ignoring
what others are doing.
Small white lady slipper, raised from
seed.
Adding inoculant to
legumes is unnecessary,
contrary to published
accounts. We
greatly underestimate
plants’ (and the bacteria
and fungi) ability to
colonize new sites.
Prairie planting on sub-soil following road grading.
Many natives colonize poor soil better than most weeds.
Three gentian species from same planting
More species, including two orchids
that came in on their own, from the
same project.
Snapper Prairie SNA, Jefferson Co.
Goose Pond
Sanctuary, MAS
Many long-lived,
“late successional”
forbs, like this
prairie dock
seedling, are the
first to germinate
after a fall or
winter planting.
Theories of plant succession also ignore the
reality of nursery production of conservative species
like this planting of dropseed, Sporobolus heterolepis.
Two year old
dropseed plant
from direct
seeding.
Site was
maintained by
mowing the first
and
second summer.
Site was former
crop land
prepared by
disking.
Sporobolus, broadcast seeded
into existing vegetation
with no herbicide, tillage, or
cover crop. Inter-seeding is a
viable option, if followed by
either mowing or fire
Seed for this planting consisted mainly of chaff from
seed cleaning plus old seed. Seed was broadcast late fall
into existing vegetation with no site prep or herbicide.
No fear of failure, low cost, and plenty of patience
achieves a similar result to a catalog perfect prairie.
Tall grass and forb buffer planting to
prevent spread of reed canary grass
at right. No site prep except mowing.
Tall grass is quite competitive and
easy to establish.
Tall grass buffer planting to prevent spread of reed
A used mower, a broadcast seeder,
and access to seed sources can
achieve the same results as special
equipment, extensive site prep.,
and seed mixes costing thousands
more.
Main ingredient:
no fear of failure.
Dodecatheon and Sporobolus planting.
Prairie/savanna relic, Devil’s Lake State Park, the
SNA model for the seed mix.
Year 2
Year 1
Year 6
Why the planting season matters:
Similar seed mix, different planting dates
ICF 1980 Fall Planting
ICF 1981 Spring Planting
15 years old (1995 photos)
27 years later, the boundary between the fall and
spring plantings is still distinct.
On native prairie, most seed is scattered by winter, and
the expensive forb seeds need cold to break seed dormancy.
Late fall and winter seeding make the best use of your most
expensive seeds.
Why a good seed mix matters:
Mature Sporobolus. What happens to the
other 100 plus seeds/sq. foot in a high density
seed mix if one seedling can occupy the entire
area when mature?
If we want the planting to have at
maturity 5% leadplant (Amorpha
canescens) abundance in 5 years, how
much Amorpha do we put in the seed
mix?
Small forb plots with
known seeding
rates at the DNR
Wilson Nursery,
Boscobel, 1993.
We use data like this
to establish
an aggressive factor
per species
for seed mix design.
Seeds per square foot, Curtis mix with
aggressive factor for mesic prairie
Amorpha canescens
Rudbeckia hirta
4.82
0.37
Pycnathemum
virginianum 2.22
1.67
Aster laevis
1.23
Euphorbia corollata
Indian grass planted at 5 pounds clean seed per acre. Some
references and nurseries recommend seeding rates 3-5 times
this rate.
Same production field, one year later.
Restoration, farming, and gardening all depend on
planting the best seeding rate for soil and conditions.
Any excess without later thinning will stunt the
growth and decrease yield of all but the most
aggressive species.
Percent by seed weight for seed mix based
on Curtis’ Plant Ecology Lab data.
29%
Grasses
Forbs
71%
Grass/Forb ratio for DNR 2012 Seed Bid
(pounds of seed purchased)
879
(18 %)
Grasses
and
Sedges
4117
(82%)
Forbs
4.7:1 ratio,
About average
for the past ten
years.
Grass to forb ratio by weight,
Premium commercial tall grass mix
Grass
49%
Forb
51%
4 species make up 42% by weight of the
DNR 2012 forb seed order
Rudbeckia
hirta ($19)
101 lbs
Dalea
66 lbs purpureum
($19)
62 lbs
139 lbs
Ratibida
pinnata ($26)
Heliopsis
helianthoides
($19)
2012 DNR forb
seed order by
seed count
25265116
Veronicastrum virginianum
16720000
Hypericum pyramid
18013300.29
Monarda
fistulosa
57658000
161268645
Rudbeckia
hirta
Oenothera
biennis
60184964
Ratibida pinnata
One out of every four forb seeds planted by
The Wisconsin DNR in 2012 was a black-eyed susan,
Rudbeckia hirta
Only 3% of the seed purchased by weight
were forbs over $100 per pound in 2012.
152
Total pounds
excluding forbs
> $100
Total pounds
forbs > $100
4762
Dominance by warm season composites and grasses
is a function of seed production costs, not a rule of
prairie ecology.
Commercial shortgrass mix, forb distribution by weight
in ounces per acre
Cassia fasciculata,
Partridge Pea
15.64
Commercial shortgrass mix by seed count
per square foot (101 seeds total for forbs)
Cassia (1.98)
Campanula
rotundifolia
12.25
58.61
Heuchera
richardsonii
Removing the burden of cost and
impatience will dramatically improve the
quality and diversity of any project.
Madison Audubon Goose Pond Sanctuary Restoration
Restoration project, Bluestem Farm, emphasis on
spring bloomers and rare species
Wetland buffer planting,
Bluestem Farm
How can we increase production of these
desirable species, especially if we have been
warned not to plant them because of cost and
perceived difficulty?
Shooting star
(right),
leadplant below.
Sometimes great
steps are needed to
speed up the
production of
foundation seed for
planting larger seed
plots.
Good demand for
these species is the
only incentive that
will boost production.
This initial seed plot
of shooting star,
started with plugs,
produced enough
to direct seed
other areas.
Five steps to diversity and authenticity while
minimizing costs:
1. Use and reward a dedicated and well trained
volunteer base.
Madison Audubon
seed collecting
and planting crew.
2. Have access to local seed sources and concentrate
on species of highest value.
3. Minimize aggressive species.
1 pound of Rudbeckia or Monarda will seed 1 acre of
seed nursery. 1 or 2 ounces or less per acre will
suffice.
4. Plant late fall or early winter.
5. Plant only as much acreage per year as the
supply of rare or expensive species allows. Adding
them later may be even more expensive and difficult.
Second year Phlox
pilosa, $2100/lb
on 2012 seed bid,
hand collected
from adjacent
remnant prairie.
Be sure to take a guided tour or visit one of our
many State Natural Areas that are open to the public.
Help ensure their survival by planting locally adapted seed
of the same species. Avoid varieties and hybrids with
artificially selected traits that may not benefit pollinators and
assist in gene flow from one remnant to another.