(800) 621-0315



Annual Plant

A plant that completes its life cycle (germination through death) in one year or growing season. Essentially non-woody plants. (Also see “Biennial Plant” and “Perennial Plant.”)

Aquatic Plant

Grows only in a body of water.

Ascending Growth Habit

Plant with branches that rise or curve upward.

Biennial Plant

A plant that completes its life cycle (germination through death) in two years or growing seasons, generally flowering only in the second growing season. Plants are non-woody above the ground. (Also see “Annual Plant” and “Perennial Plant.”)

Botanical Name

Genus and species are given. Occasionally a cultivar name follows the species name to further identify the plant. It should be noted that because the naming of plants is not an exact science, botanists sometimes reclassify plants into new genus and species names. When necessary, cross references are given on plants that may be known by more than one botanical name. )

Bunching Growth Habit

Plant that spreads by forming clumps. In grasses, they expand to fill in the turf.

Common Name

The most widely used common names for a particular plant are given for reference. Many plants go by more than one common name.

Cool Season Grass

Grasses that grow best when temperatures are between 60 and 75°F. They stay green until temperatures drop below 32°F for extended periods and can survive subfreezing temperatures. (For another category, see “Warm Season Grasses.”)


The word cultivar derives from the term “cultivated variety.” A cultivar name is often presented as the “variety name” after the genus and species in home garden seed catalogs. For example: “Nasturtium (Tropaeolum majus) Jewel Mix.” The cultivar name is “Jewel Mix.” Described by the International Code of Nomenclature as an “assemblage of cultivated plants clearly distinguished by one or more characteristics, which, when reproduced, retains its distinguishing characteristics.” A seed-grown cultivar can be either a hybrid or open-pollinated variety. So, a cultivar is a cultivated variety with specific characteristics (traits).

Deciduous Plant

Plant that loses its leaves, usually in fall and early winter. New leaves emerge in the spring. (For its opposite, see “Evergreen plant.”)

Decumbent Growth Habit

Plant that grows horizontally but with plants tips that ascend (curve upward).

Erect Growth Habit

Plant that grows upright in relation to the ground.

Evergreen Plant

Plant that has living leaves throughout the year. (For its opposite, see “Deciduous Plant.”)

Fire Hazard Plant

Plants that promote the spread of fires. Higher combustibility.

Fire Hazard Plant

Low-fuel plants that are less combustible.


see “Genetically Engineered (GE)”

Genetically Engineered (GE)

The terms GE and GMO are frequently used interchangeably in the media, but they do not mean the same thing. Genetic Engineering describes the high-tech methods used in recent decades to incorporate genes directly into an organism. The only way scientists can transfer genes between organisms that are not sexually compatible is to use recombinant DNA techniques. The plants that result would not occur in nature; they are “ genetically engineered” by human scientific intervention.

Examples of GE crops currently grown by agribusiness include Golden Rice which was genetically modified to produce vitamin A for prevention of blindness in children in some 3rd world countries. Some commercial corn varieties were modified with a naturally occurring soil bacterium for protection from corn borer damage (Bt-corn). And herbicide-resistant (“Roundup Ready”) soybeans, corn, cotton, canola, and alfalfa were developed. Each of these examples are for large acreage, commercial crops. Home gardeners could not purchase them even if they wanted to.

At the present time, home gardeners will not encounter any GE seeds in home garden seed catalogs, on garden center seed racks, or from the Stover Seed Company.

Genetically Modified Organism (GMO)

The USDA defines a GMO as an organism produced through any type of genetic modification, whether by high-tech modern genetic engineering, OR by centuries old traditional plant breeding methods. While you often hear the GE and GMO used interchangeably, they have very different meanings.
For hundreds of years (corn is a good example), genes have been manipulated by plant breeders who cross-pollinate plants and monitor the results for specific characteristics (traits) of the organism to improve productivity, quality, or performance. The techniques they use make the same kind of selections that can occur in nature. In other words, they “genetically modify organisms” and this is where the term GMO applies.
Examples of 20th century breeding work include familiar vegetables and fruits such as seedless watermelons, pluots and modern broccoli.

Germination Percentage

The typical seed germination expected under normal conditions for the listed species. These figures have been established using historical information. Actual figures can vary widely from year to year and from seed lot to seed lot. There are many environmental, biological, and cultural conditions that affect germination. When specifying seed standards, it is always best to specify seed in PLS (pure live seed) pounds.


see “Genetically Modified Organism (GMO)”

Heirloom Varieties

Heirlooms can be generally defined as open-pollinated varieties that have resulted from natural selection rather than a controlled hybridization process. Some sources use 50 years as an arbitrary age marker to define what constitutes an heirloom variety. Others classify any cultivated variety as an heirloom if it was developed prior to the 1940s and 50s because starting in the 1960s, plant breeders began producing and selling many modern hybrid varieties.

Like any other open- pollinated variety, seed saved from an heirloom produces plants with the same characteristics as the parent plant. Seed saving organizations have played an important role in preserving many noncommercial heirloom varieties.
Examples of popular home garden heirlooms include Brandywine tomatoes and Early Wonder green beans. The romantic view of heirlooms is that they are varieties that have been passed down through generations of gardeners—varieties your grandparents would know.

Hybrid (F-1)

An F-1 (first generation hybrid) occurs when a breeder selects two pure lines (plants that produce identical offspring when self-pollinated) and cross-pollinates them to produce a seed that combines desirable characteristics (traits) from both parents. Examples of desirable traits might include disease resistance, uniform plants, earliness to flower, earliness for first harvest, high nutrition, or a particular fruit or flower color.

Hybrid seed is generally much more expensive than non-hybrid seed, due to the time-consuming production methods: The pure lines must be consistently maintained so that F-1 seed can be produced each year, and the process of cross-
pollinating is often done by hand.

Seeds can be saved and planted from F-1 hybrids; however, plants grown from that seed will not look like the plants you grew the first year. They will likely lack the desirable characteristics of the parents, which were crossed specifically to incorporate them.

Examples of popular home garden hybrids include Sweet Corn Golden Beauty F1 and Sweet Corn Bi-licious F1.

Invasive Plant

A plant that has a propensity to spread (either by reseeding or by stolon growth) and tends to monopolize a plant community.

Low-Fuel Plant

Plant material that does not promote the spread of fires.


A plant that maintains a symbiotic relationship with various soil bacteria that make atmospheric nitrogen available for plant use. Members of this family include lupins, clover, alfalfa, and soybeans. They provide animal feed or green manure.

Open-Pollinated (OP)

Open-pollinated varieties are seeds that result from pollination by insects, wind, self-pollination (when both male and female flowers occur on the same plant) or other natural forms of pollination. If you save seeds from open-pollinated varieties and grow them in following years, they will “come true,” meaning that the plants will produce plants with characteristics traits) like the parent plant from which the seeds were harvested.

Keep in mind, however, that both the wind and insects will pollinate different open-pollinated varieties that are planted close together. Because of this, for some common home garden plants, notably squash and pumpkins, saving seed can be a gamble. Unless different varieties are separated by specified distances, they may exchange pollen or “cross pollinate” each other. You may end up with less productive, disappointing flowers or vegetable harvests.

Organic Seeds

When you see the word “certified Organic” on a seed packet, it has a distinct legal meaning. It can only be used for seed by growers who are following all the detailed rules and regulations specified by the USDA’s National Organic Program.

While other countries have their own organic systems, in the USA, organic regulations specify that the land in which crops are grown cannot have had prohibited substances applied for three years prior to harvest, and the operation must be managed according to an Organic System Plan that is approved and regularly inspected by a USDA accredited certifier.

Organic seeds are grown strictly without the use of synthetic fertilizers and pesticides; the use of sewage sludge, irradiation, and genetic engineering are also prohibited.

Ornamental Plant

This refers to a non-native plant that grows under cultivated conditions in the landscape.

Pelleted Seeds

Pelleted seeds are enclosed in a round pellet made from simple clay or another inert material to bulk them up. The process makes very small seeds such as lettuce, carrots, and onions easier to sow and is a way to make expensive tiny flower seeds easier to see and handle.

Pelleted seeds may also be “primed”. Priming is a hydration treatment bringing seeds to the brink of germination, and then they are dried for storage and distribution. Primed seeds break dormancy and germinate quickly when sown but should be used the same season they are purchased, as priming can decrease storage life.

Perennial Plant

Plant that lives more than two years or growing seasons. Essentially non-wood above ground. (Also see “annual” and “biennial.”)

Prostrate Plant

Plant growth habit where the plant lays flat on the ground.

Purity Percentage

This is the typical seed purity expected under normal conditions for the listed species. These figures have been established using historical information.
Actual figures can vary widely from year to year and from seed lot to seed lot. There are many environmental, biological, and cultural conditions that affect purity. When specifying seed standards, it is always best to specify seed in PLS (Pure Live Seed) pounds.


Plants can spread by underground stems or runners called Rhizomes. (See related term “Stolons)

Riparian Plants

Plants suited to riparian zones—areas that lie adjacent to freshwater courses, including perennial and intermittent streams, lakes, and other bodies of fresh water. These plant species have adapted to a wetter environment.

Seeds Per Pound

Represents seed units per bulk pound regardless of viability. This figure can vary greatly within a species due to conditions at seed harvest.


Grasses that typically spread by rhizomes, stolons, or tillers which develop into a uniform cover. They generally recover from injury or grazing.


Plants can spread by above ground stems or runners that are called stolons. (See related term: “Rhizomes”)

Treated/Untreated Seed

Seeds labeled “Treated” are generally coated with a fungicide—check the packaging for specifics about the treatment. Treated seed is available primarily for commercial crops because farmers want to protect germinating seed in the field from pathogens when planted in cold or wet soil.

Packet seed companies that sell to home gardeners generally specify if any of the seed they are offering is treated. Current rules for USDA certified organic production prohibit the use of treated seed. This might change in the future as biological seed treatments are approved for organic production and become available.

Warm Season Grass

Grasses that prefer milder, warmer climates. They grow best when temperatures are between 80 and 95°F. They lose their green color when temperatures drop below 50°F for extended periods but will recover under warmer temperatures. Some species cannot survive subfreezing temperatures. (For another category, see “Cool Season Grasses.”)

Wetland Plants

Wetlands are where soil saturation with water is the dominant factor. This generally includes swamps, marshes, bogs, and similar areas. Wetland Plants grow on the edge of bodies of water where flooding may occur.


Home Garden Seed Association, The United States Department of Agriculture, and In-House Staff.

Back to Top