Native Grass & Forb:
Establishment and Management Basics
Whether you are planting for wildlife or primarily for forage with an emphasis on wildlife all native grass and forb plantings have common planting methods and management steps that you can follow. This section will guide you through choosing seed, native plant seed dormancy and its potential issues, common species, site preparation, planting methods, and maintenance.
CHOOSING SEED AND SPECIES
When you order native grasses and forb seed all weights should be based on pure live seed. Pure live seed takes into account the amount of stems, leaves, and other inert material along with the germination rate of the seed. By ordering pure live seed you are making sure that you are paying for viable seed and not large amounts of inert materials. Many companies now sell by pure live seed, but there are still some companies that sell seed on bulk rates which often include low germination rates and large amounts of inert materials. Native grass and forb seed germination rate are variable from year to year and the amount of inert materials can also vary from year to year. A number of companies do not sell forb or legume seed based on pure live seed, but sell at bulk rates. The reason for this has to do a lot with the extreme variability of the germination/dormancy rates as well as the fact that most forb/legume seeds can be cleaned relatively easily. This does not mean that purchasing bulk seed of forbs/legumes is a good thing. Forb/legume seed is often much more expensive then native grass seed with these small amounts it can be much more critical that seeds you plant are viable and will germinate when conditions are right. It is highly recommended that you talk with your seed seller to determine if they sell forbs/legumes as PLS or bulk. Cutting corners and cost by purchasing cheap forb/legume seed can result in little to no forbs/legumes in your planting reducing its value for wildlife and potentially increasing your cost because you will have to purchase additional seed and replant to get the desired results.
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Calculating Pure Live Seed
CIMARON LITTLE BLUESTEM
Test date 12/2008
PURE SEED X TOTAL GERMINATION/100 =PLS
58.53% X 84.00%/100 = 49.17% PLS
For each bulk unit of seed, 49.17% is pure live seed.
If you wanted to purchase 10 lbs PLS
AMOUNT PLS/(PLS/100) = BULK WEIGHT
10/(49.17/100) = 20.34 lbs BULK WEIGHT
This means that when you purchased your 10 lbs of PLS, you would receive 20.34 lbs of bulk seed.
Example with High Dormancy
LITTLE BLUESTEM, CAMPER
Test date 12/2008
80.57% X 94.00%/100 = 75.74% PLS
For each bulk unit of seed, 75.74% is pure live seed.
If you wanted to purchase 10 lbs PLS
10/(75.74/100) = 13.20 lbs BULK WEIGHT
This means that when you purchased your 10 lbs of PLS, you would receive 13.20 lbs of bulk seed.
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Reading the Seed Label
Although PLS is one of the most important things to understand when ordering native grass, legume, and forb seeds, you also need to understand the quality of the seed you are getting beyond just PLS. The label on your seed will include a wealth of information. Seed companies are required by law to list the following items on the analysis tag:
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Other Crop Seed
*It is not required to list the percentage of dormant seed. Method of testing may affect whether Dormant seed is listed. Most of the time, Total Germination is reported as Germination + Dormant.
Other information that will be found on the Label include: Variety and Net Wet.
Purity is the amount of actual seed in a sample. In general, the higher the purity the better the overall quality of the seed is going to be. Usually purity by itself does not reveal much but when considered with germination, might tell you something about the seed. During cleaning, material is removed to increase the purity of the seed. Low purity with high germination could indicate a by-product of the cleaning process. Low purity with low germination could also be a by-product. High purity with low germination could mean old seed. In any of these cases it doesn't mean you don't want to buy the seed but you should expect to buy it at a discount.
Examples of other crop in native grasses would be any other native grass seeds which are not the specified crop as labeled when the sample was submitted. Any "other crop" which is greater than 5% is listed as part of the purity and the lot is then changed from the specified crop to a mixture. For example if little bluestem was submitted for analysis and a purity exam showed 6% big bluestem, the seed sample label would be changed from little bluestem to little bluestem/big bluestem mix. Other crop over 5% also will have the germination tested and reported. Other crop less than 5% will be listed but germination will not be tested. Something to be concerned about in other crop is if fescue is also listed as other crop. If fescue seed does occur in the seed it can make establishment and management of your native grasses extremely difficult. Often landowners work to kill fescue before planting their native grasses, the last thing you would want to do is be planting it with them. If other crop percent exceeds 1% inquire about what the other crop is.
There are three types of weeds: 1) prohibited noxious weeds, those which cannot be present in any amount; 2) restricted noxious weeds, those which can only be present in less than specified amounts; 3) common weeds, those whose cumulative total cannot exceed a certain percent. Seed companies are required by law to report the percent of weeds in each batch of seed and specifically name any restricted noxious weeds in excess. The amounts vary from state to state. Talk with the seed seller about any weed seed level above 1%. You should also be very cautious and suspicious of any high percentage of weeds without a declaration of noxious weeds on the label.
Small stems, leaf parts, dirt clods, insect parts, etc.-any non seed item is inert. Inert is conversely related to purity. When purity is high, inert is low and visa versa. More and more seed companies or using process that reduce the amount of inert material. In the past inert material was often high requiring 2 to 3 times as much bulk seed in order to get relatively good rates of pure live seed.
Germination is the seed which when treated by the recognized and accepted standard for germination, sprouts. (The method of germination testing varies from species to species.) Germination is expressed as a percent of sprouted seed from a known amount of seeds.
Germination is pretty straight forward. High germination rates indicate good quality seed and probably good vigor seedlings. Be cautious of low germination rates. Low germination could indicate one or more of several problems, possibly related to the storage, handling, or conditioning of the seed. However, low germination rate could also be the result of annual variation in the seed due to weather when the seed was grown. If the germination rate is below 50% you should talk with the company to see if it is just the result of annual variation or potentially old seed that was not handled properly. In order to maintain viability native grass seed should be stored at
This is seed which does not germinate readily due to a hard seed coat. Typically this is legumes, but can also include some of the native forbs. This may also be combined with "Dormant Seed" on the label.
Dormant seed is seed which did not sprout under the specified conditions but sprouted after additional treatment or stained when treated with tetrazolium. Tetrazolium (TZ) is a chemical which stains live tissue. Native grasses have dormant seed rather than hard seed.
Many times germination and total live seed are used synonymous with each other. Technically they are not the same. Total live seed is the sum of germination plus hard seed or dormant seed, depending upon the species. Total live seed is used to calculate pure live seed. All seed analyses should indicate germination and hard seed or dormant seed separately if any hard or dormant seed exists.
A seed analysis is useless without a test date. Obviously things like purity, crop, weeds and inert are not going to change over time but germination and dormant or hard seed can change dramatically. Each state has a maximum allowed time period since the last test. The test date restriction is set by each state, therefore there are several different limitations depending upon which state the seed is sold in. Nine and six months are the most common maximum limits. Always check the test date and only buy seed that has been tested within the time limit of your state, check with your State Department of Agriculture.
The test date, in some cases can tell you something about how old the seed is. Native warm season grasses are harvested during late summer through fall. Cleaning and conditioning usually occurs during fall and winter months. Seed samples are submitted for testing soon after cleaning. Be cautious of seed purchased in the fall with a test date near the 9 month limit. That seed has been carried over the summer since the last test and could have had significant loss of germination if it was not stored properly.
The state the seed was grown in will be listed as the origin. This may not necessarily be the origin of the stock seed. In other words if you are looking for seed that is ecotype seed of Iowa having a label with an Origin: IA does not mean that the seed is ecotype seed or seed that was Iowa genetic seed..
Information found under "Variety" will include cultivar/release name, species, and common name. Cultivars/release names are the names given to plants which have had seed collected and grown in order to produce certain characteristic or trait. For instance cave-in-rock switchgrass was developed for its stiff stems, upright growth for wildlife and conservation cover and forage potential. If it is not a cultivar you may also find it listed as ecotype seed from a particular state or just labeled as native. Ecotype seed are those that come from a specific area and are believed to be better adapted to the conditions found in that area. Often when restoration work is being done it is recommended that local ecotype seed is used in the restoration if it is available. You will want to talk with your seed supplier if you are interested in using ecotype seed to determine if they have it available for your area.
Net Weight (Bulk)
This is the weight of the package also called bulk weight which includes the weight of all inert material, pure seed, other crop, and weed seeds.
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Native Plant Seed DormancyUnlike domestic crops of sunflower, corn, or soybeans which all germinate the summer they are planted, native grasses and forbs require correct environmental conditions before the seeds will germinate. Native grasses, forbs, and legumes all have some level of dormancy. This dormancy can vary from year to year and with variety/ecotypes. Forbs typically have the highest dormancy rates, legumes lower rates, and most native grasses have very little although there are exceptions. Often native seeds have to go through periods at or near freezing and temperatures above 60o F for prolong periods before it will break dormancy. This means that a seed may lay in the soil for 1, 2, 3, or 100 years before germinating. You will need to take this into account when establishing native grass, legumes, and forbs for wildlife or forage. It is one of the reasons that years 1, 2, and 3 are so critical in the establishment and development of native plants from seed. It is also why in the first 2 years many people believe their plantings are complete failures.
If you look at the two examples of PLS calculation above for little bluestem you will see that Cimarron had no dormancy while Camper has 85.5% dormancy listed. If you planted these both in May the first year the Cimarron without dormancy would show significantly more germination than the Camper. In most instances if you had planted the Camper you would believe that you had a failure of your planting if little bluestem was all that you planted. In the case of the Camper little bluestem with 85.5% dormancy it would probably be better to plant it in February or early March to give the seed some cold treatment and hopefully break dormancy the first year. However, even if you did not do this, it just means the Camper will require a winter to help break dormancy, so that it will germinate the following growing season. Native forbs seeds can have the most variable germination rates. Some species of forb such as greyhead coneflower, purple coneflower, false sunflower, black-eyed Susan, and wild bergamont will germinate the summer they are planted. Other forbs like pale purple coneflower, blazing stars, compass plant, prairie dock, and butterfly milkweed will require between 30 and 90 days of cold moist stratification (temp 34 o F to 40o F in damp moist soil) before they will germinate.
Native legumes typically require 10 to 30 days of cold moist stratification. In order to improve germination it is also recommended that the seeds of legumes are scarified. Scarification is the process by which a hard seed is rubbed against sand paper or other abrasive surface in order to make the seed coat more porous. Often the cleaning process after harvest of legume seed results in enough scarification. However, you may see recommendation by some seed companies for you to scarify your legume seed before planting.
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Common Native Grass, Legumes, and Forbs Short Warm Season Grasses (1ft to 3ft)
Tall Warm Season Grasses (4ft to 8ft)
Eastern Gama grass
Cool Season Grasses (1ft to 4ft)
Canada Wild Rye
Virginia Wild Rye
Wild False White Indigo
Wild False Blue Indigo
White Prairie Clover
Purple Prairie Clover
Roundhead Bush Clover
Slender Bush clover
New England Aster
Lance Leaf Coreopsis
Pale Purple Coneflower
Rough Blazing Star
Spike Blazing Star
Southern Prairie Dock
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Site preparation for establishment will vary depending on current land use. If the area is fescue a minimum of two sprayings of glyphosate will be needed. Spray 2 quarts/acre of glyphosate in the fall (September to November) with a second spraying in the spring (March to May) of 2 quarts/acre of glyphosate and/or 10.7 oz of Journey or 2 to 4 oz of imazapic (Plateau or Panoramic). If non-imazapic resistant forbs are used you should not use Journey or imazapic during pre-establishment site preparation. Depending on the glyphosate you use you may need to add a surfactant to your mix. The surfactant will help the herbicide stick to the plants and be absorbed better into the cells of the plant.Another option is to do 2 spring sprayings of glyphosate at a rate of 2.0 quarts/acre. The first spraying should occur in late March/April with the second spraying 4 weeks later. The second spraying should also include 10.7 oz of Journey or no more than 2 to 4 oz of imazapic with seeding occurring no earlier than a week after final spraying.
For grass mixes containing sideoats grama and eastern gamagrass do not exceed 2 oz/acre imazapic or 10.7 oz/acre Journey for pre-emergence weed control. Use of post-emergence application of imazapic could result in loss of these species from the mix. Always read herbicide labels before using.If the area is a crop field then one spraying of 2.0 quarts/acre of glyphosate during the spring should be adequate. However if Johnsongrass is an issue a Fall spraying of 2.0 quarts/acre of glyphosate and 10.7 oz of Journey or 2 to 4 oz of imazapic (Plateau or Panoramic) maybe needed.
If the field you are going to plant into is an old field that has had no management for several years and has a lot of invasive and noxious weeds then you have three options. The first option is to spray the field with appropriate herbicides needed to control the noxious weeds and spray the field 3 to 4 times during the growing season with 2 quarts/acre of glyphosate. These sprayings spread over spring, summer, and late summer/early fall will help in controlling the various weeds growing in the field. You may also need to consider doing this for a second growing season to reduce competition. The second option is if the area can be cropped for 3 years then the herbicides used to control weed competition in corn and soybean can help in depleting weed competition. If you are able to go this route consider soybeans the first year, corn the second year, and and wheat or oats the final year. The soybean planting will allow grass herbicides to be used, corn will allow broadleaf control, and the wheat or oats along with the corn will help reduce the nitrogen levels in the soil. However, if glyphosate resistant corn or soybeans are used then the broad spectrum of the glyphosate will work on both grass and broadleaf weeds.
The final option is to determine what your goals are for the field and what plants are currently growing there. One possibility is to use herbicides to control the invasive and noxious weeds and then interseed additional forbs and native grasses into the field at a lower rate. This method is used to increase diversity while reducing overall maintenance of the site and having to go completely too bare ground by killing all of the vegetation. For more information see Old Field Management.
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When to PlantPlanting dates for native grasses and forbs include "Dormant Season Seeding" December 1 to March 15th and "Growing Season Seeding "March 16 to June 1. Dormant Season Seeding will give forbs which often require moist stratification of 10 to 120 days a better chance to germinate the following year. Planting during the growing season will result in the lack of germination of many forb seeds until the following growing season. Dormant seeding native grasses will also increase the germination rates of seed that typically requires some weathering to break the seed coat. Dormant season seeding does best on crop fields where weed control has been conducted for several years. If you use imazapic resistant forbs and grasses you may be able to do dormant season plantings on herbicide killed sod, but it will probably require one or more treatments of imazapic to keep weeds from over taking the new seedlings.
Another option is split seeding the planting with the forb seed planted during the dormant season and grass seed planted during the growing season. In this option typically the native grass is planted during the growing season and the forbs are planted during the dormant season the winter after the grasses have been established. This method requires multiple passes over the field and having to rent a no-till drill a second time 6 to 8 months later. In this case it may be possible to broadcast the forb seeds with a carrier over the new grass planting after the field has be mowed low in November or December when it will have no effect on the native grasses.
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Many landowners are unfamiliar with native grasses and forbs and find it difficult to understand the issues often found with planting. Native grasses throw a major monkey wrench into what is believed to be standard planting methods. For instance corn, soybeans, and wheat are typically planted with standard drill. The seeds easily separated and do not clog up the bins, tubes, or seeder. However the shear nature of native grass seed dispersal makes planting the conventional way difficult. Most native grass seeds have awns or tufts of long or stiff hairs called beards that help in dispersal of the seed whether it is wind or being caught in the fur or feathers of animals. These same appendages cause the seed to stick together in a standard grain drill seed bin and clog up seed tube or make it impossible to broadcast the seed without a carrier or additional processing. Along with the awns and beards there is often a large amount of stem and leaves mixed in with the seed that also clog up the bins and tubes.
Big bluestem, Indiangrass, little bluestem have long awns and hairs which stick together and make planting difficult. Many seed companies now sell debearded seed which has had the awns and stiff hairs completely removed or reduced to improve the ability to plant. Completely debearded seed can be planted in a conventional drill or broadcast. Native Grass No-till Drill
Native grass drills are specifically designed to deal with the awns, beards, and trash often associated with native grasses. The native grass bin has pickers that rotate to separate the seed and keep it from sticking. Native grass drill typically also have a bin that can be used for planting small seeds like those from forbs or switchgrass that do not stick together. Proper calibration of a native grass drill is essential to get the seed established properly and to make sure that you do not run out of seed. For more information on Drill Calibration.Ideally a native grass drill should have depth bands on the double disc openers to keep the seed from being planted deeper than 3/8" with a ¼" being the ideal depth. When planting you should also make sure that about 1/3 of the seed being dropped is still visible. If the drill you plan to use does not have depth bands then you will need to purchase cylinder stroke control stops. These are spacers that clamp onto the ram of the hydraulic cylinder and stop it from going all the way down. By using these stops you will be able to set the drill at the same depth every time you lower it.
Broadcasting of seed works best on ground that has been tilled and cultipacked. On ground that has not been tilled or cultipacked such as herbicide treated sod establishment of seed will take longer and be more sporadic. Broadcasting works best on small fields where proper equipment is not available or too expensive. Broadcasting seed in the winter during the dormant season often works the best. This gives the freeze thaw process, snow, and winter rains a chance to push the seed into the proper depth. It also allows forb seed to be treated so that it will break dormancy and sprout the first year.Typically mechanical broadcasting is done. Broadcast seeders include a Herd, Cyclone, Truax or other types of broadcast seeder can be used. Broadcast seeders can be worn over the shoulders, ATV/UTV, tractor, or truck mounted. Currently Truax is the only company that makes a native grass broadcast seeder that is either worn over the shoulders or mounted to an ATV. The Truax broadcast seeder has pickers that keep the fluffy native grass seed from sticking together. Other brands of Broadcast seeders will require using a carrier and/or debearded native grass seed. Forb seed can be used through almost any broadcast seeder, but requires a carrier because the small size of the seed.
Hand broadcasting can be used to establish small areas < 5 acres in size. Larger areas can be done, but require a number of people or it will take weeks to do it alone. Large areas with prepared seed beds can be done using a mechanical broadcast seeder, but require preciously calibrating your broad cast seeder so that you do not run out of seed. Also when broadcasting seed it is often recommended to increase your seeding rate 25% to 50%, so that you have enough seed. For more information on Broadcast Seeder Calibration
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Year 1Mow to 4 to 6 inches high when weeds reach 12 to 24 inches in height. If you did not use a post emergent herbicide and planted in March or April you will probably need to mow in early to mid May. The next mowing will probably be needed in mid to late June. A third mowing will be needed in mid to late July and a final mowing will probably be needed in mid to late August. These mowing will reduce competition of broadleaf weeds like mares-tail, cockleburs, musk thistle.
If Johnsongrass is an issue you may need to consider spot spraying or whole field treatment of the areas with imazapic in June or July before it reaches 12 inches. If you used native grass and forb species that are not imazapic resistant for post spraying you may want to consider using a wicking bar which will place the herbicide directly on the taller vegetation leaving the shorter native seedlings unharmed. A wicking bar is similar to a large paint roller which only places the herbicide on the vegetation that it touches. See imazapic label for recommended rates.
During the second year mowing will probably only need to be done once in early spring. Mow the vegetation no lower than 12 inches in early May to reduce competition by cool-season weeds. At this point enough of the native grasses and forbs should be established to help reduce weed competition. You can mow on a 4 to 6 week interval if you feel that broad leaf weeds are an issue, but you should not mow lower than 12 inches.
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No mowing should be done in year 3, enough of the native grasses and forbs should be established that weed competition will be reduced. Not mowing will allow many of the native forbs to flower and go to seed which will result in more plants in following years. After the third growing season enough fuel should have accumulated in order to use a prescribed fire. Native grasses and forbs are adapted to fire. If you are unable to use fire you will need to consider using strip disking or strip straying in order to maintain the native grasses
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Year 4 and beyond
After the initial establishment of the native grasses and forbs you will still have to consider management of the site. Native grasses and forbs require disturbance such as fire or strip disking to eliminate competition from woody plants like trees and shrubs. Without disturbance your field will quickly go from one of grasses and wildflowers to one of trees and shrubs and eventually a forest. If you are able to use fire you should consider burning on a 1 to 2 year rotation for the first 5 years. This will allow the native grasses and forbs to better compete with the weeds and woody vegetation that may have established during the initial establishment. After burning the field on a 1 to 2 year rotation for 5 years you can begin rotating your burn on a 2 to 4 year rotation. Additional Information on Prescribed Fire.
Strip disking is an alternative that you can use when you are unable to use fire. You can either strip the field so that it is disked every 2 years or set it up so that it is disked every 3 years. Strip disking reduces grass competition and encourages ragweed, partridge pea and other valuable forbs and legumes to germinate and grow in the disked area. This reduction in competition and disturbed soil sets back succession in the field. Disking can also help reduce encroachment of woody plants by cutting the stems and exposing roots to air. Additional Information on Strip Disking.
If you are unable to do prescribed fire and strip disking an alternative is to use strip spraying. In strip straying, a herbicide is used to kill vegetation in strips across the field. These strips reduce established grass and forb competition allowing other forbs and legumes like partridge pea and ragweed to germinate and grow. Strip straying is not an ideal method for setting back succession. Strip straying does not disturb the soil and does not remove thick layers of thatch like fire and strip disking do. However if no disturbance is done then it is likely that within a few years the grasses will become too thick for wildlife and trees and shrubs will take over the field reducing its value for many species of wildlife. Additional Information on Strip Disking.
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Additional Information on Native Grasses
PB1752 - Native Warm-Season Grasses: Identification, Establishment and Management for Wildlife and Forage Production in the Mid-South
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