Understanding Garden Terminology

As you shop for plants and seeds, understanding plant terminology will help you make better choices. This article explains some of the more common terms you will find in catalogs and at nurseries.
Understanding Garden Terminology - Articles


Photo credit: Nancy Knauss

AAS Winners

Plants receiving an “All-America Selections” designation have been tested for garden performance by a panel of expert judges. There are two categories of AAS winners, AAS National Winners perform best throughout North America, while AAS Regional Winners, perform particularly well in certain regions. By requirement, all AAS Winners are non-GMO (these terms are defined below). AAS winners are not to be confused with Proven Winners®, which is a nursery brand.

GMO (Genetically Modified Organism)

GMO is a term used to identify plants that have been modified in a laboratory using genetic engineering or transgenic technology. This is different from traditional crossbreeding methods used to produce hybrids. If you do not want to purchase any GMO plants or seeds, check to make sure the company you are buying from is a signee of the Safe Seed Pledge, which assures customers that the company does not knowingly buy or sell genetically engineered seeds.


Varieties are plants that occur naturally and offspring will have the same characteristics as the parent plant. For example, seedlings of the pink-flowering dogwood (Cornus florida var. rubra) will also be pink-flowering. In plant nomenclature, the variety is italicized and written in lower case. The variety is proceeded by “var.” (not italicized).


The term cultivar is a blended word for “cultivated variety”. Unlike a naturally occurring variety, cultivars are usually bred by humans. Many cultivars are hybrids of two plants, but they can also originate as a naturally occurring genetic mutation called a sport, such as a branch with variegated leaves.Unlike a variety, a cultivar propagated by seed does not produce a plant with the same characteristics as the parent, thus cultivars can only be propagated by cuttings, grafting or tissue culture.

In plant nomenclature, the cultivar name follows the genus and species and is set in single quotation marks. The cultivar is capitalized but is not italicized. For example, Panicum virgatum ‘Shenandoah’ (Shenandoah red switchgrass).


This term, mainly used for vegetables and fruits, designates a variety that has been grown for a long time and exhibits stable characteristics from one generation to the next. When propagated, heirloom plants are similar to the parents. Unlike hybrids, heirlooms vary greatly in size and shape, so growing them can be a bit of a surprise.


This simply means that two selected plants have been crossed, which has been done by mankind for thousands of years to improve the quality of crops or ornamental plants. Hybrids are not to be confused with GMO. Seeds from hybrid plants are referred to as F1 or F1 hybrids.

Generally, hybrid seeds are more expensive because the plants are hand-pollinated. Hybrid seeds produce plants that are true to their parents. But because hybrids have been hand-pollinated, it is not recommended to save their seeds, as the results of the next generation will not be true to the parents.


This term refers to the way that plants are pollinated. Open-pollinated plants rely on wind, insects and other methods for pollen to be transferred from one plant to another. Since pollen can be distributed by multiple methods, cross-pollination can be an issue. For example, members of the cucumber family may cross with one another. Therefore, vegetables that are prone to cross-pollination must be grown separately from other plants of different varieties; otherwise the seeds they produce will not be true-to-type.


A patent number on the nametag of a plant, or PPAF (Plant Patent Applied For) or PVR (Plant Variety Rights) following the cultivar name indicate that the plant is protected from being reproduced except with a license issued by the patent holder. Patenting a plant is a lengthy and costly process and, therefore, much less frequent than trade-marking. Plant patents have a 20-year life.

Trademark (™)

A plant name followed by the trademark sign ™ indicates that the name is protected, not the plant cultivar itself. It is a means of brand recognition for the person or other entity that developed the plant. The plant may be propagated by cuttings but may not be sold under the same name. Trademarks are renewable every ten years.