HORT 217

Some Special Terminology Used in the Plant Lecture Notes

Native Region: The geographical location where natural populations of this species in known to grow. Plants are sometimes classified as native, exotic, or hybrid. As standardized for this course, native indicates the plant is found in natural populations growing in Eastern North America. Exotic indicates plants introduced to Eastern North America from regions outside of Eastern North America. Hybrid indicates the plant is the result of a cross between two different species or genera. The "x" used in scientific names simply indicates that the plant is of hybrid origin.

USDA Hardiness Zone: This refers to the United States Department of Agriculture (USDA) Hardiness Zones established by the U.S. National Arboretum describing the average coldest temperature in winter. The numbers provided in the plant descriptions of this packet identify the Northern-most zone in which the plant will grow without regular winter damage. Click here for the USDA Hardiness Zone map.

Function: Provided are examples of common landscape usages of these plants. This list is not inclusive of all possible functions and uses.

Height and Spread: The sizes listed here are to be considered loose approximations of each plant's mature and functional size. Mature sizes listed are typical height and spread ranges attained at developmental maturity, at which time growth rate slows considerably in most cases. The size attained by plants growing in especially good or poor conditions may vary accordingly. Variation in plant genotypes, as would occur for example in seed propagated stock, or in cultivars, may also influence functional sizes.

Growth Rate: Fast growing plants may well exceed one foot of new shoot length per year, whereas slow growing plants perhaps as little one inch per year.

Texture: Refers to the visible appearrance, rather than physical feeling. Larger leaved plants appear to have a more coarse texture.

Form: Provided is a short description of the general shape and growth habit of a typical mature specimen. As for size, the form and growth habit can be influenced by genotype and environment.

Foremost Landscape Interests by Seasons: Described are the major seasons of interest with the associated esthetic feature. The most distinctive traits are usually colorful flowers, foliage, fruits, and stems, and as such, these are emphasized in this category. It should also be considered however that plants often possess interesting forms and textures, and numerous other subtle visual characters that influence plant esthetics in various seasons.

Site Requirements and Special Features: Provides basic environmental needs and preferences of the plant, such light and soil moisture requirements. Special management suggestions and unique facts about the plant may also appear here.

Light: The optimum exposure to solar radiation for each plant is often presented as either full sun (more than 6 hours direct sunlight), partial shade (2 to 6 hours of direct sunlight), or shade (less than 2 hours of direct sunlight). Shade does not mean complete darkness, but instead, complete to nearly complete screening from direct sunlight.

Soil Moisture: This description should be thought of as a range of soil moisture conditions in which the plant grows well. Importantly, the term "wet soil" when used here does not mean standing water (unless indicated), but instead a very moist soil approaching water saturation.

Limitations: Loosely defined, plants generally have one or more limitations or weaknesses as it relates to usage in the landscape. Presented are important limitations that should be considered during the plant selection process. Other limitations may be provided in the detailed descriptions for each plant available on the CD Rom.

Important Variants: This section cites important or valuable genotypes (usually cultivars or varieties) of special noteworthiness. In many cases, additional useful variants are available in the industry than listed here.

Key Recognition Features: Check here for short descriptions of distinguishing morphology that may help you delineate this species from another.